Austenite-bainite ductile iron passenger car steering knuckle, manufacturing method thereof and car

Abstract

The invention relates to an austempered ductile iron passenger car steering knuckle, a manufacturing method thereof and a car. The method comprises the following steps: step 1, establishing a maximum entity according to a boundary condition; step 2, topological optimization; step 3, structural design; step 4, designing a mold; step 5, product trial-manufacturing; the high-strength austempered ductile iron steering knuckle is designed, and the weight of the high-strength austempered ductile iron steering knuckle is equivalent to that of a cast aluminum steering knuckle while the use requirements of products are met; a core assembly process is adopted for pouring, so that the problem that a high-precision structure cannot be produced in a traditional casting mode is solved; a maximum entity is established according to boundary conditions, topological optimization is performed by using simulation software, and a lightweight austempered ductile iron steering knuckle model is established according to a topological optimization model.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile parts production, and relates to an austempered ductile iron passenger car steering knuckle and a manufacturing method thereof, and a vehicle. Background Art

[0002] Passenger car steering knuckles are mainly cast aluminum knuckles and ductile iron knuckles. Compared with aluminum alloy, ductile iron has a higher density, so the use of ductile iron knuckles will increase the overall weight of the vehicle. And with the advancement of aluminum alloy production technology and casting technology, the cost of aluminum alloy steering knuckles has gradually decreased, making it a more cost-effective choice.

[0003] With the rise of the electric new energy vehicle market, the market demand for aluminum alloy chassis structural parts is increasing. More and more OEMs choose aluminum alloy to manufacture structural parts to reduce the weight of the vehicle and improve the vehicle's mileage and handling performance. Among them, aluminum alloy steering knuckles are the most widely used in vehicles and are gradually replacing ductile iron steering knuckles.

[0004] However, with the continuous reduction in the price of complete vehicles, cost reduction has become increasingly important. Compared with aluminum alloy steering knuckles, cast iron steering knuckles have considerable cost advantages. If a cast iron steering knuckle with the same weight as aluminum alloy but greatly reduced cost can be developed, it will have very strong market competitiveness.

[0005] Patent document CN117669061A discloses a front steering knuckle design method based on topology optimization, and discloses a front steering knuckle design method based on topology optimization, including the following steps: first import the front steering knuckle design domain; construct a topology optimization model to obtain a gridded three-dimensional model, wherein the gridded three-dimensional model adopts a single material topology optimization model, and when constructing the topology optimization model, it is necessary to limit the material and its parameters, move the interface where the steering knuckle is assembled with each corresponding pair of counterparts inward by a certain distance to form an inner core grid, and isolate the inner core grid as a non-topology optimization area, define the working conditions and load steps, define the optimization response, define the objective function, and finally start the optimization program to start the optimization, and wait for the optimization result; and then check the optimized three-dimensional model. The present invention solves the problem that the current design method of the front steering knuckle is more dependent on engineering experience and the estimation of the structural strength is inaccurate. The above patent document is a steering knuckle topology optimization process, which has nothing to do with the Austempered ductile iron steering knuckle.

[0006] Patent document CN116552635A provides an additive bionic steering knuckle and a manufacturing method and a vehicle thereof. The additive bionic steering knuckle includes a steering knuckle body, a bearing hole is provided on the steering knuckle body, the steering knuckle body is connected to the wheel hub bearing through the bearing hole, and a brake caliper mounting part, an upper control arm mounting part, a front toe arm mounting part, and a trapezoidal arm mounting part are sequentially arranged along the circumference of the steering knuckle body, so that the steering knuckle body is connected to at least one of the brake caliper, the upper control arm, the front toe arm, and the trapezoidal arm, and a plurality of weight-reducing holes and a plurality of reinforcing rib structures are arranged on the steering knuckle body; the steering knuckle body is manufactured by an additive manufacturing process. By applying the technical solution of the present invention, the steering knuckle is manufactured by an additive manufacturing process and weight-reducing holes and reinforcing rib structures are arranged, while achieving the various performances of the original casting solution and the same functional requirements of the use scenario, useless materials are removed, and the purpose of lightweight design is achieved. The above patent document is a 3D printing technology rather than a casting technology.

[0007] Patent document CN116956457A discloses a forward design method for a passenger car 3D printed steering knuckle structure, which belongs to the field of passenger car design technology, including: initial geometric model design; simulation modeling; meshing; structural material and section attribute setting; constraint, load and output setting; optimization parameter setting; topology optimization calculation and structure export; topology structure reconstruction; reconstructed structure performance verification; secondary topology. The present invention forward designs the steering knuckle structure through structural topology optimization, model reconstruction, performance verification and secondary topology optimization. Breaking the limitations of traditional processes, giving full play to the role of topology optimization technology in structural lightweighting, shortening the development cycle by 40%, and reducing weight by at least 30% on the existing lightweight level. The above patent document describes a steering knuckle designed based on 3D printing technology, which has nothing to do with casting technology. Summary of the invention

[0008] The present invention provides an austempered ductile iron passenger car steering knuckle and a manufacturing method thereof, and a vehicle, which solves the following technical problems:

[0009] 1. Use simulation software to perform topological optimization on the steering knuckle, find the best force transmission path, reduce material redundancy, and design the best product structure to meet the force requirements.

[0010] 2. The product weight is equivalent to or even lighter than cast aluminum products, so as to achieve the effect of cost reduction and weight reduction.

[0011] 3. Design the optimal casting process according to the product structure to ensure the casting molding.

[0012] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0013] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions:

[0014] A method for manufacturing an austempered ductile iron passenger car steering knuckle comprises the following steps:

[0015] Step 1. Establish the maximum entity according to the boundary conditions;

[0016] Step 2. Topology optimization:

[0017] Step 3. Structural design;

[0018] Step 4. Mold design;

[0019] Step 5. Product trial production.

[0020] Furthermore, the maximum entity is established according to the boundary conditions as described in step 1, specifically including: removing the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and drive shaft movement area and ensuring a certain amount of clearance, and removing the caliper and dust shield design area; at the same time, setting the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and caliper installation point surrounding area as a non-topological optimization area.

[0021] Furthermore, the topology optimization in step 2 specifically includes:

[0022] 2.1 Model establishment: Import the largest entity into the simulation software, use tetrahedron for meshing, build a topology optimization model, set the material to Austempered ductile iron QTD900-8, and set the parameters.

[0023] 2.2 Set boundary conditions, define working conditions, establish constraints and apply loads, define design variables and objective functions;

[0024] 2.3 Start the program for optimization.

[0025] Furthermore, the structural design described in step 3 specifically includes: designing a three-dimensional model of an Austempered ductile iron steering knuckle with a branch-like structure according to the topological optimization results, conforming to the optimal force transmission path and achieving the best material distribution, performing stiffness strength analysis on the three-dimensional model, repeatedly optimizing the product structure, and obtaining three-dimensional data of the Austempered ductile iron steering knuckle that meets the product requirements.

[0026] Furthermore, the mold design in step 4 specifically includes:

[0027] 4.1 Carry out upper and lower mold separation to make the parting surface;

[0028] 4.2 Design the pouring system, use low-pressure technology, pour from the bottom, and design the sprue at the bottom;

[0029] 4.3 Fill the hollow position based on the parting surface, and design the upper sand mold, lower sand mold and small core according to the product structure.

[0030] Furthermore, the product trial production in step 5 specifically includes: using austempered ductile iron for low-pressure casting to obtain an austempered ductile iron steering knuckle.

[0031] Furthermore, the 3mm area around the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and caliper mounting point is set as a non-topology optimization area.

[0032] An austempered ductile iron passenger car steering knuckle is manufactured by the method described above.

[0033] A steering knuckle of an austempered ductile iron passenger car is made of austempered ductile iron QTD900-8 material.

[0034] A vehicle has a steering knuckle, wherein the steering knuckle adopts the above-mentioned Austempered ductile iron passenger car steering knuckle.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention designs a high-strength austempered ductile iron steering knuckle, which meets the requirements of product use and has a weight comparable to that of a cast aluminum steering knuckle.

[0037] 2. The core assembly process is used for casting to solve the problem of high-precision structures that cannot be produced by traditional casting methods. The maximum entity is established according to the boundary conditions, and topology optimization is performed using simulation software. A lightweight Austempered ductile iron steering knuckle model is established based on the topology optimization model. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described below in conjunction with the accompanying drawings:

[0039] Figure 1 To establish the maximum entity according to the boundary conditions Figure 1 ;

[0040] Figure 2 It is the schematic diagram of the stiffness simulation model;

[0041] Figure 3 It is the schematic diagram of strength simulation model;

[0042] Figure 4 It is a schematic diagram of the three-dimensional data of the steering knuckle;

[0043] Figure 5 It is a schematic diagram of the parting surface of the product;

[0044] Figure 6 Schematic diagram of the pouring system Figure 1 ;

[0045] Figure 7 Schematic diagram of the pouring system Figure 2 ;

[0046] Figure 8 A schematic diagram for filling the hollowed-out position;

[0047] Fig. 9 It is a three-dimensional schematic diagram of the upper sand mold, the lower sand mold and the small core combined mold;

[0048] Fig.10 To establish the maximum entity according to the boundary conditions Figure 2 ;

[0049] Fig.11 This is a schematic diagram of the topology optimization process;

[0050] Fig.12 The present invention is a flow chart of a method for manufacturing an austempered ductile iron passenger car steering knuckle.

[0051] In the figure:

[0052] 1 is the No. 1 front upper control arm, 2 is the No. 1 front lower control arm, 3 is the No. 2 rear upper control arm, 4 is the No. 2 rear lower control arm, 5 is the toe control arm, 6 is the caliper, 7 is the dust disc, and 8 is the wheel hub bearing and drive shaft. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the embodiment of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings.

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "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 invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0055] The present invention is described in detail below in conjunction with the accompanying drawings:

[0056] The present invention provides an embodiment of a method for manufacturing an austempered ductile iron passenger car steering knuckle, referring to Fig.12 , including the following steps:

[0057] 1. Create the largest entity based on boundary conditions: See Figure 1 , Fig.10 , remove the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and drive shaft movement area and ensure a certain amount of clearance, remove the caliper and dust plate design area. At the same time, set the 3mm area around the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and caliper installation point as a non-topology optimization area to avoid material loss in this area after topology optimization that seriously affects the structural design.

[0058] 2. See Fig.11 , topology optimization:

[0059] 2.1 Model establishment: The largest entity is imported into HyperMesh software, and the mesh is divided using tetrahedron to construct a topology optimization model. The material is set to austempered ductile iron QTD900-8, the tensile strength is set to 1450 MPa, the yield strength is set to 700 MPa, the elastic modulus is set to 169 kMPa, the density is set to 7.1 g / cm3, and the Poisson's ratio is set to 0.27; the simulation software is the existing technology, using Altair's HyperMesh and Optistruct software.

[0060] 2.2 Set boundary conditions, define working conditions, establish constraints and apply loads, and define design variables and objective functions. Define nine typical working conditions, including vertical impact, turning working condition, reverse braking, maximum braking, maximum acceleration, lateral impact, forward handbrake, reverse handbrake, and curb impact, and six enterprise standard high-load working conditions, including wheel center upward high load, wheel center forward high load, wheel center backward high load, three-level high load to the right of the ground contact point, torsional high load, and braking high load. In the typical working conditions, vertical impact, turning working condition, maximum acceleration, lateral impact, and curb impact constrain the wheel center 1-6 degrees of freedom in the directions, and reverse braking, maximum braking, forward handbrake, and reverse handbrake constrain 1234, 6 degrees of freedom and control The degrees of freedom in the tangent direction of the action point; the enterprise standard large load condition constrains the degrees of freedom in 1-6 directions; according to the load decomposition calculation and analysis report of the typical limit working condition of the rear suspension system and the enterprise standard large load decomposition calculation and analysis report of the rear suspension system, the load of each point of action in each working condition is input; the design variables are defined, the mesh size is set to 2mm, the minimum member size is set to 5mm, the maximum member size is set to 30mm, the volume fraction is set to 0.2, the target response is set to minimum flexibility, and the response constraints are displacement response and volume fraction response; the objective function is set to weight minimization.

[0061] 2.3 See also Figure 2 , Figure 3 , start the program for optimization.

[0062] 3. Structural design: see Figure 4 According to the topological optimization results, a three-dimensional model of the Austempered ductile iron steering knuckle with a branch-like structure was designed to meet the optimal force transmission path and material distribution. The three-dimensional model was subjected to rigidity analysis, and the product structure was repeatedly optimized to obtain the three-dimensional data of the Austempered ductile iron steering knuckle that met the product requirements. The three-dimensional data is Figure 4 The three-dimensional data of the steering knuckle that meets the product requirements is shown.

[0063] The original cast aluminum structure steering knuckle weighs 4.9Kg, and the Austempered ductile iron steering knuckle designed using topology optimization weighs 4.8Kg, a 2% weight reduction.

[0064] 4. Mould design:

[0065] 4.1 See Figure 5 , carry out upper and lower mold separation and make the parting surface.

[0066] 4.2 See also Figure 6 , Figure 7 , design the pouring system, pour from the bottom, directly to the design below.

[0067] 4.3 See also Figure 8 , Fig. 9 , fill the hollow position based on the parting surface, and design the upper sand mold, lower sand mold and small core according to the product structure.

[0068] 5. Product trial production: Use Austempered ductile iron QTD900-8 for low-pressure casting to obtain Austempered ductile iron steering knuckle.

[0069] The present invention provides another embodiment, an austempered ductile iron passenger car steering knuckle, which is manufactured by the austempered ductile iron passenger car steering knuckle manufacturing method.

[0070] The present invention provides another embodiment, a vehicle, the vehicle is equipped with a steering knuckle. The steering knuckle adopts the above-mentioned austempered ductile iron passenger car steering knuckle and is manufactured by the above-mentioned austempered ductile iron passenger car steering knuckle manufacturing method.

[0071] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A method for manufacturing an austempered ductile iron passenger car steering knuckle, characterized in that: The following steps are involved: Step 1. Establish the maximum entity according to the boundary conditions; Step 2. Topology optimization: Step 3. Structural design; Step 4. Mold design; Step 5. Product trial production.

2. The method for manufacturing an austempered ductile iron passenger car steering knuckle according to claim 1, characterized in that: The maximum entity is established according to the boundary conditions as described in step 1, specifically including: removing the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and drive shaft movement area and ensuring a certain amount of clearance, and removing the caliper and dust plate design area; at the same time, the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and caliper installation point surrounding area are set as non-topological optimization areas.

3. The method for manufacturing an austempered ductile iron passenger car steering knuckle according to claim 1, characterized in that: The topology optimization described in step 2 specifically includes: 2.1 Model establishment: Import the largest entity into the simulation software, divide the mesh using tetrahedron, build a topology optimization model, set the material to Austempered ductile iron QTD900-8, and set the parameters; 2.2 Set boundary conditions, define working conditions, establish constraints and apply loads, define design variables and objective functions; 2.3 Start the program for optimization.

4. The method for manufacturing an austempered ductile iron passenger car steering knuckle according to claim 1, characterized in that: The structural design described in step 3 specifically includes: designing a three-dimensional model of an Austempered ductile iron steering knuckle with a branch-like structure according to the topological optimization results, conforming to the optimal force transmission path and achieving the best material distribution, performing stiffness and strength analysis on the three-dimensional model, repeatedly optimizing the product structure, and obtaining three-dimensional data of the Austempered ductile iron steering knuckle that meets the product requirements.

5. The method for manufacturing an austempered ductile iron passenger car steering knuckle according to claim 1, characterized in that: The mold design described in step 4 specifically includes: 4.1 Carry out upper and lower mold separation to make the parting surface; 4.2 Design the pouring system, use low-pressure technology, pour from the bottom, and design the sprue at the bottom; 4.3 Fill the hollow position based on the parting surface, and design the upper sand mold, lower sand mold and small core according to the product structure.

6. The method for manufacturing an austempered ductile iron passenger car steering knuckle according to claim 1, characterized in that: The product trial production described in step 5 specifically includes: using austempered ductile iron for low-pressure casting to obtain an austempered ductile iron steering knuckle.

7. The method for manufacturing an Austempered ductile iron passenger car steering knuckle according to claim 2, characterized in that: The 3mm area around the No. 1 front upper control arm, No. 1 front lower control arm, No. 2 rear upper control arm, No. 2 rear lower control arm, toe control arm, wheel hub bearing and caliper mounting point is set as a non-topology optimization area.

8. An Austempered Ductile Iron Passenger Car Steering Knuckle, characterized by: The method is prepared by any one of claims 1 to 7.

9. The austempered ductile iron passenger car steering knuckle according to claim 8, characterized in that: Made of Austempered Ductile Iron QTD900-8 material.

10. A vehicle, characterized in that: The vehicle has a steering knuckle, and the steering knuckle is the Austempered ductile iron passenger car steering knuckle according to claim 8.

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