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

Abstract

The invention provides a vehicle composite material connecting rod mold based on thermal expansion forming and a manufacturing control method. The composite material connecting rod mold for the vehicle is made of 6061 aluminum alloy, and a parting surface is built at the round corner contour line of the upper surface of a mold cavity in the mold; the upper die is designed into a three-section type die assembly module, so that the die assembly efficiency and the connecting rod end forming quality are improved; thermal expansion foam containing grooves are formed in the outer ends of inner cavity rings of the upper die and the lower die, buckling deformation of fibers at the ends of the connecting rod is avoided, and the mechanical property of the rod piece is guaranteed. The three-dimensional mold drawing block is embedded in the parting surface of the lower mold, and meanwhile, an inner cavity of the upper mold is avoided, so that mold drawing efficiency is guaranteed, and meanwhile, glue overflowing and blocking are prevented. The mold is suitable for a thermal expansion forming process to prepare a composite material special-shaped pipe fitting structure, and the problems that in the preparation process of an existing mold, mold drawing and mold closing are difficult, glue spills out, and the forming quality is poor are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of automobile connecting rod manufacturing dies, and 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 number of cars in the world, a series of problems such as energy shortage and environmental pollution are becoming increasingly prominent. Lightweighting of automobiles can significantly reduce energy consumption and environmental pollution, effectively increase the service life of key components, and improve the comfort and safety of automobiles. Therefore, it has become an important development trend in the current automobile industry, and it is also one of the key strategies to improve fuel economy, reduce emissions and improve overall performance. Carbon fiber composite materials are widely used in automobile manufacturing due to their advantages such as light weight, high strength, high rigidity and corrosion resistance. Among them, composite connecting rods, as one of the core components of the chassis system, are an important breakthrough point for achieving vehicle lightweighting. Compared with traditional metal connecting rods, composite connecting rods can not only significantly reduce weight, but also improve vibration and noise characteristics, while improving durability and thermal performance. Therefore, in order to achieve large-scale manufacturing of composite connecting rods, the development of mold technology is crucial. At present, the mold design of composite connecting rods mainly aims at high precision, high efficiency and high reliability, and at the same time needs to adapt to the needs of complex geometric shapes and different molding processes.

[0003] However, there is no precedent for the use of composite materials in the existing connecting rods. Due to the lack of a simple and efficient preparation process and the small number of corresponding composite material preparation molds, traditional molds cannot be adapted to 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 finished product and production efficiency. The above pain points make it difficult for traditional molds to accurately and quickly perform thermal expansion molding on carbon fiber composite connecting rods, and cannot meet market demand. Summary of the invention

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

[0005] 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 mold and the lower mold are made of 6061 aluminum alloy, and the parting surface between the upper mold and the lower mold is established at the contour line of the fillet 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;

[0008] The upper mold is configured with three mold clamping modules, the mold clamping modules include a first-stage mold clamping module, a second-stage mold clamping module and a third-stage mold clamping module, the dividing line of the three mold clamping modules is at a diameter perpendicular to the forming direction of the end metal ring, and the three mold 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 periphery of 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 of the heat expansion foam offset outwards from both ends of the inner cavity after expansion.

[0011] The parting surface of the lower mold is provided with four inlay grooves, which 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 model 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 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 form.

[0013] Furthermore, in a preferred embodiment of the present invention, the inlay groove and the three-dimensional lifting module are clearance fit, a φ10 threaded hole is provided in the middle of the three-dimensional lifting module, and the mold is lifted by screwing in a bolt, the three-dimensional lifting module is 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 fit 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. Three positioning and fastening through holes are provided in the first-stage mold module and the second-stage mold module, and eight are provided in the third-stage mold 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, and the upper mold portion is lifted up by screwing in a bolt to touch the parting surface of the lower mold, and two demolding threaded holes are provided in the first-stage mold module and the second-stage mold module, and are arranged in parallel, and two are also provided in the three-stage mold module, and 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 along 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 a vehicle based on thermal expansion molding, which is applied to any of the composite connecting rod molds for a vehicle based on thermal expansion molding, and comprises the following steps:

[0018] Obtain the processing requirements of the target connecting rod, and perform thermal expansion forming of the connecting rod based on the processing requirements of the target connecting rod. During the thermal expansion forming process, the thermal expansion parameters of the composite connecting rod mold are calculated by finite element calculation software to construct a finite element model of the thermal expansion forming 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, and the deformation parts and the ultimate deformation load of each deformation part during heating of the composite material are extracted according to the structural working condition model;

[0020] The actual heating temperature gradient output by the composite connecting rod mold during the continuous heating process is obtained, and the thermal stress cloud map during the heating process of the composite material is divided into N sub-cloud blocks based on the actual heating temperature gradient, and the Laplace matrix of each sub-cloud block located in the structural working condition model is constructed, and the eigenvectors in the Laplace matrix and the eigenvalues ​​of each eigenvector are calculated;

[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, and deformation clustering is performed on each row of the sub-cloud blocks of the new Laplace matrix based on the extreme deformation load;

[0022] After deformation clustering is completed, a clustering result of thermal stress associated with the deformation part is generated. The stress deformation law of the composite material under the heating temperature gradient is determined by analyzing the clustering result. Based on the stress deformation law, the temperature parameters of the composite material thermal expansion molding in 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 a predetermined thermal expansion forming working condition of a composite connecting rod mold under different preset connecting rod processing requirements, and constructing a connecting rod processing and forming system of the composite connecting rod mold according to the predetermined thermal expansion forming working condition;

[0025] The similarities between the target connecting rod processing requirements and different preset connecting rod processing requirements are calculated one by one, and the connecting rod processing forming system corresponding to the preset connecting rod processing requirement with the maximum similarity is extracted, which is defined as the target connecting rod processing forming system of the target connecting rod processing requirement;

[0026] Based on the big data network, a finite element mechanical model of a steel connecting rod that meets the processing requirements of the target connecting rod is obtained, 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 through finite element calculation software;

[0027] Determine, based on the maximum stress value, the maximum displacement deformation and the natural frequency, the benchmark initial performance index that the thermal expansion of the composite material should follow when the composite connecting rod mold meets the target connecting rod processing requirements; wherein the benchmark initial performance index includes 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 building a standard composite connecting rod model according to the index threshold value specified for each benchmark initial performance index;

[0029] By performing thermal expansion molding of 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 of 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 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 fiber types that can be used to manufacture connecting rods for composite connecting rod molds are obtained, and based on the prepreg process flow, the types of resin matrix materials and fiber types 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 the composite materials through a target connecting rod processing and forming system to obtain a thermal expansion characteristic index of each discrete combination of the composite materials, and generating a simulated thermal expansion characteristic radar chart of each discrete combination of the composite materials based on the thermal expansion characteristic index of the radar chart;

[0033] Obtaining an optimal thermal expansion characteristic radar map that meets the standard composite connecting rod model, registering the optimal thermal expansion characteristic radar map with each simulated thermal expansion characteristic radar map, and calculating 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 schemes 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] Acquire actual temperature data of the composite material in the process of thermal expansion forming and the distribution points of each actual temperature data, construct a thermal map, and fit and draw each of the actual temperature data on the thermal map based on the distribution points to generate an actual temperature thermal distribution map of the composite material in the process of thermal expansion forming;

[0038] The Hamiltonian method is introduced, and the Hamiltonian function is constructed on the actual temperature and thermal distribution diagram output by the finite element model of thermal expansion forming of composite materials to obtain the Hamiltonian canonical equation. 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] Acquire a preset temperature control strategy for the composite material, and divide 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 the big data network. Based on the color gamut coding rules, the color gamut change coding of temperature and thermal expression is read and written when the composite connecting rod mold manufactures the standard composite connecting rod model based on the optimal thermal expansion characteristic radar chart, and a temperature and thermal color gamut distribution change query table is generated;

[0041] Obtaining a current color gamut distribution change code set for each sub-model region, and if any current code in the current color gamut distribution change code set can be queried 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] Based on the model color gamut pattern diagram, 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 are controlled.

[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 mold-drawing threaded holes and meticulous parting surface design ensure that the mold improves loading and unloading efficiency while ensuring the quality of the rod ends and overall molding. The thermal expansion foam design ensures 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 drawing module and the stepped groove design facilitate loading and unloading, effectively avoiding interference and damage to the rods and molds. The even distribution of 8 bolts in the middle of the mold and 3 bolts on 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, drawings of other embodiments can be obtained based on these drawings without paying creative work.

[0047] Figure 1 This is a schematic diagram of the upper mold and lower mold structure 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 This is the 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 The 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 starting module;

[0053] Figure 7 Schematic diagram of the 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. Positioning 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 purposes, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the structures related to the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict.

[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", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the 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 technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, "multiple" means two or more.

[0058] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0059] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[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 shape of the connecting rod and the contour line of the rounded corner of the upper surface of the connecting rod of the inner cavity 104, 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 with traditional steel molds, the density of aluminum alloy is only one-third of that of steel. The present invention can greatly reduce the weight by using 6061 aluminum alloy for high-speed cutting to make molds. The opening and closing speed of the mold made of lightweight aluminum alloy can be significantly improved during use, and the portability is enhanced, which makes the transportation and operation of aluminum alloy parts more convenient and quick, and the production efficiency is greatly improved. On the one hand, the thermal conductivity of aluminum alloy is 4 times that of steel, so the use of aluminum alloy material can significantly shorten the cooling time of the mold, and there is no need to install 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 electric spark processing efficiency reach 4 to 5 times that of steel, thereby further effectively reducing the processing cost of the mold material. Therefore, the mold material of the present invention using aluminum alloy can optimize the process performance of the design and processing of the mold itself, and can greatly improve the thermal conductivity and electrical conductivity during thermal expansion processing. Since the cutting speed of aluminum alloy can reach more than 5 times that of steel, the processing time of molds can be greatly reduced, which effectively shortens the cycle from mold design to mass production, allowing mold products to be quickly put on the market. In addition, the unique excellent processing performance of aluminum alloy can also significantly reduce the loss of processing tools, which helps to extend the service life of processing tools. In summary, aluminum alloy has the advantages of excellent welding performance, good cutting performance and short production cycle, which can improve the quality and efficiency of mold mass production processing.

[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 matching 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, ensure the uniformity of pressure and heat conduction during processing or use, and make the assembly of the mold more reasonable; and the thickness of the mold circumference and the upper mold 101 and the lower mold 102 meet the standard tolerance range, so that it remains uniform, ensuring the feasibility and performance stability of the thermal expansion manufacturing of the composite material in the mold, which is conducive to improving the heat transfer efficiency and minimizing the impact of the temperature gradient. 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 with three mold modules, which include a first-stage mold module 105, a second-stage mold module 106 and a third-stage mold module 107. The dividing line of the three mold modules is at a diameter perpendicular to the forming direction of the end metal ring. The three mold modules are tightly connected without gaps.

[0065] The lower die 102 is provided with two metal ring positioning truncated cones, the lower bottom surface diameter of the metal ring positioning truncated cones 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 closes the mold from top to bottom normally, and is mainly responsible for the main forming area of ​​the connecting rod, while the first-stage mold closing module 105 and the second-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, especially for scenes with complex shapes or materials that require high pressing accuracy, facilitates rapid mold closing, and reduces wrinkles or bubbles on the prepreg on the rod caused by improper mold closing. 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 by 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 communicates 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 offset outward from the two ends of the inner cavity 104 after expansion.

[0068] It should be noted that the setting of the heat expansion foam placement groove 108 can realize the prepreg molding of the connecting rod end during the heat expansion molding process. The mold setting is offset by 2.25cm. The precise size of 2.25cm is because the external heat expansion foam needs to be placed in 3 layers, and the single layer is 0.5mm. After the expected expansion of 1.5 times, it will present a 2.25mm shape. Therefore, a 2.25cm heat expansion foam placement groove is made to provide a stable space for the heat expansion foam. It should be noted here that the heat expansion foam is inside at the middle position of the connecting rod, but the heat expansion foam laying position at the heat expansion foam placement groove is located in the metal ring part. At this time, the position of the heat expansion foam of the metal ring part is at the outermost part, that is, the heat expansion foam placement groove. After the molding is completed, the heat expansion foam will be removed. At this time, only the carbon fiber composite material is retained outside the metal ring of the connecting rod at the end. The purpose is to increase the tensile stiffness and reduce the outer size constraint of the ring. The 2.25mm size of the heat expansion foam placement groove is based on the fact that the heat expansion foam has a size of 2.25mm after expansion. This setting effectively reduces the fiber buckling deformation problem caused by the heat expansion foam at the bottom of the connecting rod being inside and the heat expansion foam at the end of the metal ring being outside, making the overall appearance of the connecting rod smoother. It prevents it from moving during heating or pressurization, and improves the molding accuracy of the prepreg; in the complex structure 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 heat 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, and avoid material damage or deformation due to uneven pressure distribution when the mold is closed.

[0069] The parting surface 103 of the lower mold 102 is provided with four inlay grooves, which 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, and 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 being 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 mold is removed by screwing in a bolt. The three-dimensional lifting module 109 is 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 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 molding shape of the connecting rod, ensure the integrity of the connecting rod molding, and help improve the surface smoothness of the connecting rod workpiece. 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 the three-dimensional lifting modules 109 to lift them up, the rods are evenly stressed, which can make the force transmission during demolding more stable without damaging the rods, thus helping to 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 in a diagonal shape.

[0073] It should be noted that when closing the mold, the locating pin on the parting surface 103 of the lower mold 102 is aligned with the locating pin slot on the parting surface 103 of the upper mold 101 and inserted into the positioning assembly. The locating pin 202 adopts the form of tightening on the top and loosening on the bottom through precise size and shape, that is, it is a clearance fit relative to the upper mold and an 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 ensure the quality and performance of the final product. The use of the locating pin 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 pin 202 can ensure the accurate position of the rod, thereby protecting the mold and the rod from damage, greatly reducing the cost of frequent replacement and maintenance of the mold. At the same time, the use of the locating pin 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 disassembly of the nut.

[0075] The 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 the eight positioning and fastening through holes 203 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 three-stage clamping module 107 has 8 positioning and fastening through holes 203, which are mainly used to fix the stress area of ​​the mold, which helps to control the pressure distribution in the middle and avoid warping or demolding problems in the middle. The one-stage clamping module 105 and the two-stage clamping module 106 each have 3 positioning and fastening through holes 203, which can evenly distribute the pressure on both sides, optimize the pressure transmission at the end of the mold, and reduce material defects caused by uneven local force. The uniform arrangement of the 14 positioning and fastening through 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. The bolt is screwed in and touches the parting surface 103 of the lower mold 102 to partially lift up the upper mold 101. Two demolding threaded holes 204 are provided in the first-stage mold module 105 and the second-stage mold module 106, and are arranged in parallel; two are also provided in the third-stage mold 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 be screwed 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] A rectangular overflow glue groove 205 is provided on the parting surface 103 of the lower mold 102. The overflow glue groove 205 is opened along both sides of the parting surface 103 of the lower mold 102, and three overflow glue 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 will overflow from the prepreg and the thermal expansion foam. If it is not discharged in time, the prepreg interlayer resin content will be too much, resulting in local resin enrichment of the rod, loose interlayers, and reduced interface bonding performance. Therefore, in order to improve the quality of thermal expansion molding of the rod, the excess epoxy resin in the inner cavity 104 should be removed as much as possible, so it is necessary to set up an overflow groove 205 to complete it. In order to more effectively realize the function of the overflow groove 205, the overflow groove 205 is opened on the parting surface of the lower mold in this mold, thereby ensuring that the resin inside the product is filled and playing a role in balancing the pressure.

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

[0082] Obtain the processing requirements of the target connecting rod, and perform thermal expansion forming of the connecting rod based on the processing requirements of the target connecting rod. During the thermal expansion forming process, the thermal expansion parameters of the composite connecting rod mold are calculated by finite element calculation software to construct a finite element model of the thermal expansion forming 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, and the deformation parts and the ultimate deformation load of each deformation part during heating of the composite material are extracted according to the structural working condition model;

[0084] The actual heating temperature gradient output by the composite connecting rod mold during the continuous heating process is obtained, and the thermal stress cloud map during the heating process of the composite material is divided into N sub-cloud blocks based on the actual heating temperature gradient, and the Laplace matrix of each sub-cloud block located in the structural working condition model is constructed, and the eigenvectors in the Laplace matrix and the eigenvalues ​​of each eigenvector are calculated;

[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, and deformation clustering is performed on each row of the sub-cloud blocks of the new Laplace matrix based on the extreme deformation load;

[0086] After deformation clustering is completed, a clustering result of thermal stress associated with the deformation part is generated. The stress deformation law of the composite material under the heating temperature gradient is determined by analyzing the clustering result. Based on the stress deformation law, the temperature parameters of the composite material thermal expansion molding in the manufacturing process of the composite material connecting rod mold are intelligently controlled.

[0087] It should be noted that composite materials can cope with the high-intensity deformation load impact that the connecting rod is subjected to during use with reasonable lamination characteristics and reasonable sleeve-rod connection structure, which can make the connecting rod not easily deformed. One of the indicators that determine the deformation quality of the connecting rod product of this mold 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 cause 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 easy to deform 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. In this regard, this method uses finite element calculation software to establish a numerical model of thermal expansion forming of composite materials, that is, a finite element model of thermal expansion forming of composite materials. The finite element model of thermal expansion forming can clearly show the specific conditions of thermal stress and self-deformation of composite materials 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, the thermal stress cloud map generated by temperature change is accurately clustered to the specific parts where deformation occurs during the thermal expansion of composite materials by clustering the eigenvalues ​​of the Laplace matrix, so that the stress deformation law of composite materials under the heating temperature gradient can be clearly revealed. According to the stress deformation law, the unreasonable temperature parameters that cause the deformation of the connecting rod composite material can be further traced, so that the temperature parameters of thermal expansion forming of composite materials in the manufacturing process of composite connecting rod molds can be accurately and intelligently controlled. 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 composite connecting rod molds, thereby realizing accurate guidance and control of the manufacturing process, greatly improving the forming 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 a predetermined thermal expansion forming working condition of a composite connecting rod mold under different preset connecting rod processing requirements, and constructing a connecting rod processing and forming system of the composite connecting rod mold according to the predetermined thermal expansion forming working condition;

[0090] The similarities between the target connecting rod processing requirements and different preset connecting rod processing requirements are calculated one by one, and the connecting rod processing forming system corresponding to the preset connecting rod processing requirement with the maximum similarity is extracted, which is defined as the target connecting rod processing forming system of the target connecting rod processing requirement;

[0091] Based on the big data network, a finite element mechanical model of a steel connecting rod that meets the processing requirements of the target connecting rod is obtained, 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 through finite element calculation software;

[0092] Determine, based on the maximum stress value, the maximum displacement deformation and the natural frequency, the benchmark initial performance index that the thermal expansion of the composite material should follow when the composite connecting rod mold meets the target connecting rod processing requirements; wherein the benchmark initial performance index includes 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 building a standard composite connecting rod model according to the index threshold value specified for each benchmark initial performance index;

[0094] By performing thermal expansion molding of 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 the matrix material and fiber type. Therefore, in the manufacturing process, it is necessary to fully study the thermal expansion characteristics of the composite materials used and select materials with appropriate thermal expansion characteristics to control their dimensional changes during heating and cooling. Composite material structure design cannot simply directly replace traditional metal materials. Therefore, composite materials should fully follow the relevant performance indicators of traditional steel connecting rod structures to perform material selection to ensure that the connecting rods formed by thermal expansion of composite materials can meet the load impact of different mechanical strength application scenarios and avoid the occurrence of connecting rod fracture and deformation. Therefore, this method determines the target connecting rod processing system required by the target connecting rod processing requirements by a similar method, and then uses the maximum stress value, maximum displacement deformation and natural frequency under different working conditions contained in the finite element mechanical model of the steel connecting rod to further analyze the overall performance of the composite material when the mold reaches the target connecting rod processing system, and then can accurately determine the benchmark initial performance indicators that the composite material thermal expansion should follow based on the performance of the steel connecting rod, thereby ensuring that the thermal expansion forming of the composite material is based on the performance standard of the steel connecting rod. Finally, the simulated thermal expansion processing method is used to analyze and calculate the difference between the simulated thermal expansion characteristics of the composite material and the optimal thermal expansion characteristics to select materials. This method can fully study and analyze the thermal expansion characteristics of the composite material based on the performance index of the steel connecting rod, so as to select the appropriate composite material to manufacture the connecting rod. On the one hand, it improves the performance reliability of the connecting rod material selection following the traditional metal standard and reduces the mechanical transmission abnormality of the composite connecting rod; on the other hand, it reduces the intervention error of traditional manual material selection, reduces the rework rate of the connecting rod production, saves manpower and material cost output, and greatly 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 of 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 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 fiber types that can be used to manufacture connecting rods for composite connecting rod molds are obtained, and based on the prepreg process flow, the types of resin matrix materials and fiber types 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 the composite materials through a target connecting rod processing and forming system to obtain a thermal expansion characteristic index of each discrete combination of the composite materials, and generating a simulated thermal expansion characteristic radar chart of each discrete combination of the composite materials based on the thermal expansion characteristic index of the radar chart;

[0099] Obtaining an optimal thermal expansion characteristic radar map that meets the standard composite connecting rod model, registering the optimal thermal expansion characteristic radar map with each simulated thermal expansion characteristic radar map, and calculating 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 schemes 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, but there are many types of resin matrix materials and fiber materials that can be used for connecting rod manufacturing, and there are also differences in the thermal expansion characteristics between different types of resin matrix materials and fiber materials. Therefore, for the selection of composite materials, it is necessary to conduct thermal expansion screening analysis with the best thermal expansion characteristics of the composite materials in the mold as the goal. For this, this method first designs different 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 simulate thermal expansion processing is performed on the composite materials of these combined layers 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 tedious steps of traditional manual thermal expansion tests on each composite material combination one by one, greatly improving the efficiency of material selection. Then, the best thermal expansion characteristic radar chart that meets the standard composite connecting rod model is constructed. The best thermal expansion characteristic radar chart is an evaluation standard. Therefore, as long as the thermal expansion characteristic threshold shown in the best radar chart is higher than that, the composite material combination under the simulated thermal expansion characteristic can be judged as a qualified material solution, that is, the radar area deviation is less than the preset radar area deviation. This method can replace the cumbersome steps of traditional manual test material selection, reduce the phenomenon that the thermal expansion characteristics of artificially selected materials do not meet the best product production of the mold, reduce the thermal expansion forming error of the connecting rod, and further improve and optimize the quality of the connecting rod product.

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

[0104] Acquire actual temperature data of the composite material in the process of thermal expansion forming and the distribution points of each actual temperature data, construct a thermal map, and fit and draw each of the actual temperature data on the thermal map based on the distribution points to generate an actual temperature thermal distribution map of the composite material in the process of thermal expansion forming;

[0105] The Hamiltonian method is introduced, and the Hamiltonian function is constructed on the actual temperature and thermal distribution diagram output by the finite element model of thermal expansion forming of composite materials to obtain the Hamiltonian canonical equation. 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] Acquire a preset temperature control strategy for the composite material, and divide 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 the big data network. Based on the color gamut coding rules, the color gamut change coding of temperature and thermal expression is read and written when the composite connecting rod mold manufactures the standard composite connecting rod model based on the optimal thermal expansion characteristic radar chart, and a temperature and thermal color gamut distribution change query table is generated;

[0108] Obtaining a current color gamut distribution change code set for each sub-model region, and if any current code in the current color gamut distribution change code set can be queried 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] Based on the model color gamut pattern diagram, 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 are controlled.

[0111] It should be noted that the key to thermal expansion molding is to control the rate and temperature distribution of the heating and cooling process. By optimizing the heating rate, cooling rate and thermal expansion process of thermal expansion molding, the excessive expansion or contraction of the material can be avoided to the maximum extent, so as to ensure the accuracy and integrity of the connecting rod forming. However, the traditional mold does not have the control of the heating rate, cooling rate and thermal expansion process in the thermal expansion molding process, and there is a large control deviation, which makes the final thermal expansion molding product of the connecting rod unsatisfactory, and there may be abnormal thermal stress or uneven shrinkage. Therefore, this method constructs an actual temperature thermodynamic distribution map reflecting the temperature size, change and migration by using the actual temperature data of the composite material in the thermal expansion molding process and the distribution point of each actual temperature data, and then introduces the Hamiltonian method to describe the Hamiltonian function of the actual temperature thermodynamic distribution, and generates an actual temperature thermodynamic dynamic model expressed by the color gamut change distribution. The model can show the change of the temperature size and migration distribution of the connecting rod during the thermal expansion process. Therefore, the temperature change and distribution of the thermal expansion of the connecting rod can be analyzed by the model to make corresponding adjustments to the heating rate, cooling rate and thermal expansion process of its manufacturing process.

[0112] It should be noted that this method adopts the color gamut coding rule to construct a temperature thermal color gamut distribution change query table by coding the temperature color gamut change 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 determine whether the actual temperature 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 resulting in unreasonable temperature size and temperature distribution of the connecting rod composite material. This method can be used to 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, so as to control the integrity and reliability of the connecting rod structure during the thermal expansion process, help the composite material maintain shape stability during the forming process, reduce performance defects of the connecting rod product, and improve the forming quality.

[0113] The above is based on the ideal embodiment of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A composite connecting rod mold for a vehicle based on thermal expansion molding, the composite connecting rod mold for a vehicle comprising an upper mold and a lower mold, characterized in that: The upper mold and the lower mold are made of 6061 aluminum alloy, and the parting surface between the upper mold and the lower mold 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 with three mold clamping modules, the mold clamping modules include a first-stage mold clamping module, a second-stage mold clamping module and a third-stage mold clamping module, the dividing line of the three mold clamping modules is at a diameter perpendicular to the forming direction of the end metal ring, and the three mold 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 at the periphery of 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 of the heat expansion foam offset outwards from both ends of the inner cavity after expansion. The parting surface of the lower mold is provided with four inlay grooves, which 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 model 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, and 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 lifted 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 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. Three positioning and fastening through holes are provided in the part of the first stage clamping module and the part of the second stage clamping module, and eight are provided in the part of 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 mold-lifting threaded hole. The theory of the mold-lifting threaded hole is the same as that of the three-dimensional mold-lifting module. The upper mold part is lifted up by screwing in the bolt and touching the parting surface of the lower mold. There are two mold-lifting threaded holes in the first-stage mold module and the second-stage mold module, and they are arranged in parallel. There are also two mold-lifting threaded holes in the third-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: The parting surface of the lower mold is provided with rectangular overflow glue grooves, which are 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.

7. A manufacturing control method for a composite connecting rod mold for a vehicle based on thermal expansion molding, applied to a composite connecting rod mold for a vehicle based on thermal expansion molding as claimed in any one of claims 1 to 6, characterized in that: The steps include: Obtain the processing requirements of the target connecting rod, and perform thermal expansion forming of the connecting rod based on the processing requirements of the target connecting rod. During the thermal expansion forming process, the thermal expansion parameters of the composite connecting rod mold are calculated by finite element calculation software to construct a finite element model of the thermal expansion forming 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, and the deformation parts and the ultimate deformation load of each deformation part during heating of the composite material are extracted according to the structural working condition model; The actual heating temperature gradient output by the composite connecting rod mold during the continuous heating process is obtained, and the thermal stress cloud map during the heating process of the composite material is divided into N sub-cloud blocks based on the actual heating temperature gradient, and the Laplace matrix of each sub-cloud block located in the structural working condition model is constructed, and the eigenvectors in the Laplace matrix and the eigenvalues ​​of each eigenvector are calculated; 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, and deformation clustering is performed on each row of the sub-cloud blocks of the new Laplace matrix based on the extreme deformation load; After deformation clustering is completed, a clustering result of thermal stress associated with the deformation part is generated. The stress deformation law of the composite material under the heating temperature gradient is determined by analyzing the clustering result. Based on the stress deformation law, the temperature parameters of the composite material thermal expansion molding in 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 a predetermined thermal expansion forming working condition of a composite connecting rod mold under different preset connecting rod processing requirements, and constructing a connecting rod processing and forming system of the composite connecting rod mold according to the predetermined thermal expansion forming working condition; The similarities between the target connecting rod processing requirements and different preset connecting rod processing requirements are calculated one by one, and the connecting rod processing forming system corresponding to the preset connecting rod processing requirement with the maximum similarity is extracted, which is defined as the target connecting rod processing forming system of the target connecting rod processing requirement; Based on the big data network, a finite element mechanical model of a steel connecting rod that meets the processing requirements of the target connecting rod is obtained, 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 through finite element calculation software; Determine, based on the maximum stress value, the maximum displacement deformation and the natural frequency, the benchmark initial performance index that the thermal expansion of the composite material should follow when the composite connecting rod mold meets the target connecting rod processing requirements; wherein the benchmark initial performance index includes 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 building a standard composite connecting rod model according to the index threshold value specified for each benchmark initial performance index; By performing thermal expansion molding of 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 is characterized in that: The method of thermal expansion forming composite material discrete combinations of different resin matrix material types and fiber types, fitting a simulated thermal expansion characteristic radar chart of each composite material discrete combination after simulated thermal expansion processing, and performing thermal expansion material selection analysis on each simulated thermal expansion characteristic radar chart and a thermal expansion characteristic radar chart of a standard composite material 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 fiber types that can be used to manufacture connecting rods for composite connecting rod molds are obtained, and based on the prepreg process flow, the types of resin matrix materials and fiber types 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 the composite materials through a target connecting rod processing and forming system to obtain a thermal expansion characteristic index of each discrete combination of the composite materials, and generating a simulated thermal expansion characteristic radar chart of each discrete combination of the composite materials based on the thermal expansion characteristic index of the radar chart; Obtaining an optimal thermal expansion characteristic radar map when meeting a standard composite connecting rod model, registering the optimal thermal expansion characteristic radar map with each simulated thermal expansion characteristic radar map, and calculating radar area deviations between the simulated thermal expansion characteristic radar maps 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 schemes 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: Acquire actual temperature data of the composite material in the process of thermal expansion forming and the distribution points of each actual temperature data, construct a thermal map, and fit and draw each of the actual temperature data on the thermal map based on the distribution points to generate an actual temperature thermal distribution map of the composite material in the process of thermal expansion forming; The Hamiltonian method is introduced, and the Hamiltonian function is constructed on the actual temperature and thermal distribution diagram output by the finite element model of thermal expansion forming of composite materials to obtain the Hamiltonian canonical equation. 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. Acquire a preset temperature control strategy for the composite material, and divide 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 the big data network. Based on the color gamut coding rules, the color gamut change coding of temperature and thermal expression is read and written when the composite connecting rod mold manufactures the standard composite connecting rod model based on the optimal thermal expansion characteristic radar chart, and a temperature and thermal color gamut distribution change query table is generated. Obtaining a current color gamut distribution change code set for each sub-model region, and if any current code in the current color gamut distribution change code set can be queried 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; Based on the model color gamut pattern diagram, 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 are controlled.

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