Rubber suspension main spring and optimization design method thereof

Abstract

The invention discloses a rubber suspension main spring and an optimization design method thereof, and relates to the technical field of electric vehicle power assembly suspension systems. The method comprises the following steps: (a) completing the structural design of the rubber suspension main spring, carrying out finite element analysis on three-direction static stiffness of the rubber suspension main spring, and obtaining static stiffness values in U, V and W directions according to the finite element analysis of the rubber suspension main spring; (b) comparing a static stiffness value obtained by simulation analysis with a theoretical value; and (c) if a large gap exists between the simulation value and the theoretical value, key structure parameters of the rubber suspension main spring are adjusted, the step (a) and the step (b) are repeated until the simulation value and the theoretical value are basically consistent (the relative error is smaller than or equal to 5%), and then optimization design of the rubber suspension main spring is completed. The problem of early failure caused by stress concentration of a traditional suspension main spring is effectively solved, and the suspension main spring is suitable for an electric automobile power assembly suspension system with the high precision requirement.

Description

Technical Field

[0001] The invention relates to the technical field of electric vehicle powertrain suspension systems, and more specifically to a rubber suspension main spring and an optimization design method thereof. Background Art

[0002] As an important part of the powertrain suspension system, the rubber suspension is composed of key parts such as the rubber main spring, metal inner core and metal outer jacket. This structure is not only simple and clear, but also has a simple manufacturing process, which greatly improves production efficiency. The rubber suspension can not only reduce the vibration transmitted from the engine to the frame, reduce the vibration and noise of the whole vehicle, and improve ride comfort, but also reduce the vibration damage to the powertrain caused by road excitation, which is beneficial to improving the NVH of the whole vehicle. Reasonable static characteristics of the suspension are necessary to avoid interference between the powertrain and the body and surrounding components and control the displacement of the powertrain. The reasonable design of the suspension main spring parameters determines the vibration isolation effect of the suspension. The suspension should not be too soft or too hard. Therefore, how to optimize the selection of suspension stiffness in the early suspension design is an extremely important issue. To ensure that the rubber suspension has a stable vibration isolation effect for a long time, it is necessary that it does not fail when subjected to loads under different working conditions. Adjusting the optimization method of the rubber suspension structural parameters is beneficial to improving the fatigue life of the suspension.

[0003] Electric vehicle powertrains often use pure rubber suspensions to reduce costs and improve reliability due to their large torque and small vibration excitation. In the prior art, bushing-type rubber suspension main springs (such as X-type and figure-eight) have been widely used, but their designs mostly rely on empirical formulas and lack systematic optimization of key structural parameters (such as the angle θ, width L, and height H of the rubber main reinforcement), resulting in insufficient stiffness matching accuracy. In addition, traditional methods do not fully consider details such as the curved surface depression, fillet size, and rubber coating thickness of the rubber main reinforcement in durability design, which can easily lead to stress concentration or debonding failure. After searching, Chinese patent document CN111310380A discloses a design and development method for the rubber bushing structure of the electric vehicle powertrain suspension. By establishing a rigid modal analysis model of the motor powertrain suspension system, the modal frequency, decoupling rate and stiffness value of the rubber bushing of the optimized suspension system are obtained; and the motor powertrain suspension system is comprehensively analyzed in combination with 36 load conditions of the vehicle; the structure of the rubber bushing is optimized by finite element analysis, and then the stiffness value of the previous rubber bushing is verified and checked. If the conditions are met, trial production can be carried out. However, it does not involve parameter optimization based on finite element analysis and comprehensive test verification, resulting in poor product performance consistency. Summary of the invention

[0004] 1. Problem to be solved

[0005] In view of the technical problems existing in the prior art, the present invention provides a rubber suspension main spring and an optimization design method thereof, which reduces the three-way stiffness matching error and improves its durability through structural parameter optimization and refined simulation design.

[0006] 2. Technical solution

[0007] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0008] The rubber suspension of the electric vehicle powertrain includes a front suspension cushion assembly, a left suspension cushion assembly and a right suspension soft point assembly, wherein the suspension rubber main springs of the front suspension cushion assembly, the left suspension cushion assembly and the right suspension soft point assembly adopt the same structure and material, and the suspension rubber main spring includes an X-shaped bushing type main spring, a metal outer jacket and a metal inner core. Therefore, the rubber suspension main spring of the present invention can be applicable to the front suspension cushion assembly, the left suspension cushion assembly and the right suspension soft point assembly.

[0009] A first aspect of the present invention provides an optimization design method for a rubber suspension main spring, wherein the structure of the rubber suspension main spring is an X-shaped bushing type, and the method comprises the steps of:

[0010] (a) Complete the structural design of the rubber suspension main spring, perform finite element analysis on the three-dimensional static stiffness of the rubber suspension main spring, and obtain the static stiffness values ​​in the U, V, and W directions based on the finite element analysis of the rubber suspension main spring;

[0011] (b) Compare the static stiffness values ​​obtained from the simulation analysis with the theoretical values;

[0012] (c) If there is a large gap between the simulated value and the theoretical value, adjust the key structural parameters of the rubber suspension main spring and repeat steps (a) and (b) until the simulated value is basically consistent with the theoretical value (relative error is less than or equal to 5%), thus completing the optimization design of the rubber suspension main spring.

[0013] According to any embodiment of the first aspect of the present invention, in step (a), the structure of the rubber suspension main spring is designed by selecting the key structural parameters of the main rib, namely the angle θ, width L and height H, as well as the values ​​of the curved surface depression radius, inner and outer chamfer radius and rubber coating thickness set on the side of the main rib, to structurally design the rubber body, outer sleeve and inner core of the rubber suspension main spring.

[0014] The structural parameters of the main rib of the rubber suspension main spring include angle θ, width L and height H, wherein the angle θ is 45° to 60°, the width L is 8 to 12 mm, and the height H is 15 to 20 mm; the curved concave radius of the side of the main rib is 1 to 2 mm, the inner and outer fillet radius is R1.5 to 2 mm, and the rubber coating thickness is 1 to 2 mm, wherein:

[0015] (1) During the compression process, the rubber main reinforcement is squeezed and expanded too much, resulting in stress concentration, which affects its durability. Therefore, the side of the rubber main reinforcement is generally not designed directly as a flat surface, but as a curved surface that is concave 1 to 2 mm inward;

[0016] (2) To increase the durability of the rubber main spring, the inner and outer sides of the rubber main ribs need to be rounded, and the recommended rounding size is R1.5~2mm;

[0017] (3) Since the distance between the inner and outer end surfaces of the rubber main rib after rounding has an impact on the durability of the rubber suspension, the distance should not be too short and is recommended to be greater than 1.5 mm;

[0018] (4) To prevent the rubber from being squeezed or stretched and debonded from the outer jacket and inner core, the thickness of the rubber coating should not be too thick or too thin, and should be kept at 1 to 2 mm;

[0019] (5) The reduced diameter size of the bushing type rubber suspension has an impact on the stiffness and durability of the rubber suspension. Therefore, the size of the reduced diameter size needs to be reasonably specified based on factors such as material properties.

[0020] According to any implementation of the first aspect of the present invention, in step (a), the finite element analysis of the three-dimensional static stiffness of the rubber suspension main spring includes: 1) simplifying the rubber suspension main spring, removing the limit blocks in the U direction and the W direction, and retaining only the rubber main ribs and the fillet part; importing the simplified rubber suspension main spring model into HyperMesh software in STP file format, and constructing the finite element model of the rubber suspension main spring by using hexahedral mesh division;

[0021] 2) MR constitutive model: The MR constitutive model is used to describe the mechanical behavior of the rubber body. The model formula is:

[0022] W=C 10 (I 1 -3)+C 01 (I 2 -3)

[0023] Where: C 10 , C 01 are constitutive model parameters;

[0024] C 10 , C 01 It is related to the hardness of the rubber material. When the rubber hardness is 43HA, C 10 =0.00636, C 01 = 0.2444, assign constitutive model parameters to the finite element model;

[0025] 3) The unit nodes on the inner ring surface of the rubber main spring are coupled with the elastic center point, a radial displacement load of 1 mm is applied to the outer ring surface of the rubber main spring, and the six degrees of freedom of the outer surface of the rubber suspension are constrained; at the elastic center point, a displacement load of 3 mm is applied to the rubber suspension in the U, V, and W directions respectively;

[0026] 4) In the post-processing part, the correlation values ​​of the reaction force and displacement of the elastic center point of the simplified model are obtained, the reaction force value corresponding to the displacement of 0-2mm is extracted, and the linear stiffness curve of the suspension in all directions is plotted according to the extracted value. The slope of the curve is the linear stiffness value of the rubber suspension in all directions.

[0027] This step of the present invention can effectively verify the structural design accuracy of the rubber suspension main spring by performing finite element analysis on its linear static stiffness, thereby avoiding an increase in development costs and an increase in development cycle due to inaccurate structural design.

[0028] A second aspect of the present invention provides a rubber suspension main spring, which is obtained by using the optimization design method described in the first aspect.

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The optimization design method of the present invention, through structural parameter optimization and refined simulation design, makes the three-way stiffness matching error of the rubber suspension main spring ≤5%, and the durability is improved by more than 30%, which effectively solves the problem of early failure of the traditional suspension main spring caused by stress concentration, and is suitable for the electric vehicle powertrain suspension system with high precision requirements;

[0032] (2) The rubber suspension main spring structure of the present invention is optimized in design. The rubber main rib adopts an angle θ=45°~60°, a width L=8~12mm, and a height H=15~20mm. Combined with the curved surface depression (depression amount 1~2mm) and inner and outer chamfers (R1.5~2mm), stress concentration is effectively reduced. The thickness of the rubber coating is controlled to 1~2mm to prevent debonding and improve the interface bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0034] Figure 1 It is a schematic diagram of the structural parameters of the rubber suspension main reinforcement of the present invention;

[0035] Figure 2 It is a schematic diagram of other structural parameters of the rubber suspension of the present invention;

[0036] Figure 3 It is a structural schematic diagram of the rubber suspension main spring of the present invention;

[0037] Figure 4 It is a simplified finite element model of the rubber part of the present invention;

[0038] Figure 5 Interaction and load settings for the present invention;

[0039] Figure 6 It is the U-direction stress cloud diagram and static stiffness curve of the present invention;

[0040] Figure 7 It is the V-direction stress cloud diagram and static stiffness curve of the present invention;

[0041] Figure 8 It is the W-direction stress cloud diagram and static stiffness curve of the present invention. DETAILED DESCRIPTION

[0042] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is only for the purpose of illustrating and not limiting the description of the characteristics and features of the present invention, so as to propose the best mode for performing the present invention and to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0043] The following detailed description of the present invention and example embodiments may be better understood in conjunction with the accompanying drawings, in which elements and features of the present invention are identified by reference numerals.

[0044] Since the suspension rubber main springs of the designed powertrain suspension system adopt the same structure and material, only the structure of one of the rubber suspension main springs needs to be designed, so the present invention designs the rubber suspension main spring of the front suspension. First, the three-way static stiffness ratio of the rubber suspension main spring of the front suspension is shown in Table 1-2.

[0045] Table 1-2 Front suspension cushion assembly stiffness ratio

[0046]

[0047] The optimization design method of the rubber suspension main spring of the present invention, wherein the structure of the rubber suspension main spring is an X-shaped bushing type, comprises the steps of:

[0048] (a) Complete the structural design of the rubber suspension main spring, perform finite element analysis on the three-dimensional static stiffness of the rubber suspension main spring, and obtain the static stiffness values ​​in the U, V, and W directions based on the finite element analysis of the rubber suspension main spring;

[0049] (b) Compare the static stiffness values ​​obtained from the simulation analysis with the theoretical values;

[0050] (c) If there is a large gap between the simulated value and the theoretical value, adjust the key structural parameters of the rubber suspension main spring and repeat steps (a) and (b) until the simulated value is basically consistent with the theoretical value (relative error is less than or equal to 5%), thus completing the optimization design of the rubber suspension main spring.

[0051] like Figure 1 As shown, when the main spring of the bushing type rubber suspension is structurally designed, the key structural parameters of the main rubber ribs are adjusted to ensure that the three-dimensional static stiffness of the main spring of the front suspension meets the design requirements. In step (a), the structural design of the main spring of the rubber suspension is to select the key structural parameters of the main ribs, including the angle θ, width L and height H, as well as the values ​​of the concave radius of the curved surface set on the side of the main ribs, the radius of the inner and outer fillets and the thickness of the rubber coating, and structurally design the rubber body, outer jacket and inner core of the main spring of the rubber suspension.

[0052] Among them, the structural parameters of the main ribs of the rubber suspension main spring include an angle θ, a width L and a height H, wherein the angle θ is 45° to 60°, the width L is 8 to 12 mm, and the height H is 15 to 20 mm; the curved concave radius of the side of the main rib is 1 to 2 mm, the inner and outer chamfer radii are R1.5 to 2 mm, and the rubber coating thickness is 1 to 2 mm.

[0053] It should be emphasized that when designing the structure of the rubber suspension, it is necessary to pay attention to some parameters that affect the durability of the rubber suspension, such as Figure 2 As shown:

[0054] (1) During the compression process, the rubber main rib is squeezed and expanded too much, resulting in stress concentration, which affects its durability. Therefore, the side of the rubber main rib is generally not designed directly as a plane, but as a curved surface that is concave 1 to 2 mm inward; (2) In order to increase the durability of the rubber main spring, the inner and outer sides of the rubber main rib need to be rounded, and the recommended rounding size is R1.5 to 2 mm; (3) Since the distance from the inner and outer end surfaces of the rubber main rib after rounding has an impact on the durability of the rubber suspension, the distance should not be too short, and it is recommended to be greater than 1.5 mm; (4) In order to prevent the rubber from being squeezed or stretched and debonding from the outer jacket and inner core, the thickness of the rubber coating should not be too thick or too thin, and should be maintained at 1 to 2 mm; (5) The reduced diameter size of the bushing type rubber suspension has an impact on the stiffness and durability of the rubber suspension, so the size of the reduced diameter size needs to be reasonably specified based on factors such as material properties.

[0055] By adjusting the key structural parameters θ, L, H of the rubber main spring, according to the parameter design requirements that affect the durability of the rubber suspension, combined with the nonlinear stiffness curve of the front suspension cushion assembly, the rubber body, vulcanized outer jacket and vulcanized inner core of the rubber suspension main spring are structurally designed. Figure 3 shown.

[0056]

Simplification and meshing of rubber suspension main spring model

[0057] Since the vulcanized outer shell and inner core are made of metal, their deformation resistance is much greater than that of rubber materials, so the vulcanized outer shell and inner core can be regarded as rigid bodies. Therefore, when performing static analysis on the main spring of the rubber suspension, only the rubber part needs to be analyzed.

[0058] Simplifying the model can reduce the complexity of calculations, improve calculation efficiency, and make simulation analysis faster and more efficient. The linear static stiffness of the rubber suspension is mainly determined by the hardness of the rubber material and the main rubber ribs, and has nothing to do with the limit blocks. Therefore, when simplifying the rubber part, remove the limit blocks in the U and W directions, and only keep the main rubber ribs and fillets. Import the simplified rubber part model into the HyperMesh software in the STP file format to mesh the model.

[0059] A good mesh quality can provide a solid foundation for numerical analysis, effectively accelerate the solution process, and obtain more accurate solutions. In three-dimensional finite element simulation analysis, hexahedral mesh has significant advantages in calculation accuracy, convergence speed, and anti-distortion ability. Therefore, this paper uses hexahedral mesh to establish finite element model. The finite element model is as follows: Figure 4 As shown in the figure, the quality of the finite element mesh is evaluated. The overall quality of the mesh units is good. A few mesh units with poor quality are located at the inner and outer rubber encapsulation areas, which have no effect on the simulation results.

[0060] When the rubber material is in a small deformation, the MR model can accurately describe its mechanical behavior. Therefore, when performing finite element analysis on the bushing rubber suspension, the MR constitutive model is used to describe the mechanical behavior of the rubber part, and the model formula is:

[0061] W=C 10 (I 1 -3)+C 01 (I 2 -3)

[0062] Where: C 10 , C 01 are constitutive model parameters;

[0063] C 10 , C 01 It is related to the hardness of the rubber material. When the rubber hardness is 43HA (Shore hardness), C 10 =0.00636, C 01 =0.2444. And the constitutive model parameters are assigned to the finite element model.

[0064] In order to reduce the number of iterations in the subsequent calculation process, the surface unit nodes of the rubber inner ring need to be coupled with the elastic center point. The model is constrained according to the relationship between the rubber suspension and the passive end bracket; the bushing type rubber suspension and the suspended bracket are interference fit, and the interference is 2mm, so a 1mm radial displacement load is applied to the outer ring surface of the rubber part and the 6 degrees of freedom of the outer surface of the rubber suspension are constrained. Figure 5 As shown, displacement loads of 3 mm are applied to the rubber suspension in the U, V, and W directions at the elastic center point, and a schematic diagram of the coupling processing results and the constraint results is obtained.

[0065] like Figure 6 , Figure 7 and Figure 8 As shown, the stress cloud diagrams and stiffness curves corresponding to the U, V, and W directions of the rubber suspension are shown. According to the above settings, the finite element model is subjected to static simulation analysis. In the post-processing part, the relevant values ​​of the reaction force and displacement of the elastic center point of the simplified model can be obtained, and the corresponding reaction force value when the displacement is 0-2mm can be extracted. The linear stiffness curve of the suspension in each direction is drawn according to the extracted value, and the slope of the curve is the linear stiffness value of the rubber suspension in each direction.

[0066] Based on the finite element analysis of the rubber suspension, the static stiffness values ​​in the U, V, and W directions are obtained, and the static stiffness values ​​obtained by the simulation analysis are compared with the theoretical values, as shown in Table 1-3.

[0067] Table 1-3 Comparison of simulated and theoretical values ​​of static stiffness of rubber suspension

[0068]

[0069] It can be seen from Tables 1-3 that the simulated values ​​of the three-way static stiffness of the bushing type rubber suspension of this embodiment are basically consistent with the theoretical values, and the relative errors in the U, V and W directions are 4.7%, 4.8% and 2.2% respectively. It should be noted that when designing the rubber suspension structure, it is difficult to achieve the ideal value of the static stiffness value in each direction. The maximum error of the three-way static stiffness of the rubber suspension is 4.8%, which is within a reasonable range. Therefore, the structure of the rubber suspension meets the design requirements.

[0070] The present invention achieves better consistency of rubber suspension main springs of the same batch through structural parameter optimization and refined simulation design. At the same time, the three-way stiffness matching error of the rubber suspension main springs of the same batch is ≤5%, and the durability is improved by more than 30%. This effectively solves the problem of early failure of traditional suspension main springs caused by stress concentration, and is suitable for electric vehicle powertrain suspension systems with high precision requirements.

[0071]

Dynamic and static stiffness test of rubber suspension main spring

[0072] For the dynamic and static stiffness test of the rubber suspension main spring of the present invention, the test device is an MTS833 dynamic instrument, which has a measurement range of ±25KN, a maximum operating frequency of 80Hz, and an accuracy level of 1. It can measure the dynamic and static stiffness of the three degrees of freedom of the rubber suspension main spring. The equipment meets the dynamic and static stiffness test requirements.

[0073] The MTS833 dynamic instrument is used to conduct bench tests on the main spring of the rubber suspension to verify whether the static and dynamic performance of the main spring sample of the rubber suspension meets the technical requirements. In the test preparation stage, the rubber suspension is pressed into the test fixture. The rubber suspension and the test fixture are interference fit with an interference of 2mm, and the test fixture is installed on the dynamic instrument.

[0074] The ambient temperature during the test is 23℃±2℃. The dynamic and static stiffness test conditions and requirements of the rubber suspension main springs U, V, and W are shown in Table 1-4.

[0075] Table 1-4 Dynamic and static stiffness test conditions and requirements for rubber suspension main springs

[0076]

[0077] When testing the dynamic and static stiffness of the main spring of the rubber suspension, the number of samples tested was 3, and the loading speed was 10min / mm. Since the rubber material has the Mullins effect, in order to minimize the influence of the Mullins effect on the accuracy of the test data, three pre-cycle loadings are required before the formal test to ensure the reliability of the test data. The final test data takes the reaction force-displacement curve of the fourth loading process, and the stiffness value is calculated. The test results of the dynamic and static stiffness of the main spring of the rubber suspension are shown in Table 1-5.

[0078] Table 1-5 Dynamic and static stiffness test results of rubber suspension main spring

[0079]

[0080]

[0081] It can be seen from Tables 1-5 that the test results of the three-axis static stiffness and W-axis dynamic stiffness of the rubber suspension main spring sample are all qualified.

[0082]

High temperature creep test of rubber suspension main spring

[0083] In actual practice, the main spring of rubber suspension is often subjected to long-term loads, and creep tests are required to evaluate its performance under long-term loads to ensure that the main spring of rubber suspension will not fail or degrade due to long-term loads. In order to verify that its long-term performance meets the design requirements, a high-temperature creep test is conducted on the main spring of rubber suspension using a creep test chamber GT-7049-DH3. The compression stroke range of the test equipment is 0.0001 to 30.000 mm, the test environment temperature range is 0 to 150 ° C, and the temperature control accuracy can reach ± ​​2 ° C, which meets the requirements of the creep test equipment for the main spring of rubber suspension. The creep test conditions and requirements for the main spring of rubber suspension are shown in Table 1-6.

[0084] Table 1-6 Test conditions and requirements for dynamic and static stiffness of rubber suspension main spring

[0085]

[0086] In the test preparation stage, the main spring of the rubber suspension is pressed into the test fixture, and the test fixture is installed in the creep test box. The temperature in the temperature control box is set to 95°C, and a load of -195N is applied to the W direction of the rubber suspension.

[0087] When testing the long-term performance of the rubber suspension main spring, the number of test samples is 3. The creep test results are shown in Table 1-7.

[0088] Table 1-7 Creep test results of rubber suspension main spring

[0089]

[0090]

[0091] It can be seen from Table 1-7 that among the three samples tested, the maximum creep amount is only 0.213mm, and the static stiffness change rate is only 5.4%, which is far lower than the design requirement (the smaller the better).

[0092]

Durability test of rubber suspension main spring

[0093] In order to evaluate the durability of the rubber suspension main spring, it is necessary to use the MTS durability test equipment to carry out bench fatigue life test. The test conditions and requirements for the bench fatigue life of the rubber suspension main spring are shown in Table 1-8.

[0094] Table 1-8 Test conditions and requirements for fatigue life of rubber suspension main springs

[0095]

[0096] In the test preparation stage, the rubber suspension main spring is pressed into the test fixture, and the test fixture is installed in the MTS durability test equipment. The temperature in the temperature control box is set to 80°C, and the load in the W direction is set as shown in Table 1-8. During the test, every 5 cycles, observe whether the rubber suspension main spring in the temperature control box has cracks.

[0097] When evaluating the durability performance of the rubber suspension main spring, the number of test samples is 2. After 15 cycles, the fatigue life test results of the rubber suspension main spring are shown in Table 1-9.

[0098] Table 1-9 Fatigue life test results of rubber suspension main spring (15 cycles)

[0099]

[0100] As shown in Table 1-9, after 15 cycles, the permanent deformation and dynamic and static stiffness attenuation rate of the rubber suspension main spring meet the technical requirements, and there are no cracks on the surface. Therefore, the bench fatigue life test of the rubber suspension main spring continues until the rubber suspension main spring cracks, or after 20 cycles, the test is stopped.

[0101] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for optimizing the design of a rubber suspension main spring, wherein the structure of the rubber suspension main spring is an X-shaped bushing type, characterized in that: The method comprises the steps of: (a) Complete the structural design of the rubber suspension main spring, perform finite element analysis on the three-dimensional static stiffness of the rubber suspension main spring, and obtain the static stiffness values ​​in the U, V, and W directions based on the finite element analysis of the rubber suspension main spring; (b) Compare the static stiffness values ​​obtained from the simulation analysis with the theoretical values; (c) If there is a large gap between the simulated value and the theoretical value, adjust the key structural parameters of the rubber suspension main spring and repeat steps (a) and (b) until the simulated value is basically consistent with the theoretical value, thus completing the optimization design of the rubber suspension main spring.

2. The optimization design method of the rubber suspension main spring according to claim 1 is characterized in that: In step (a), the structure of the rubber suspension main spring is designed by selecting the key structural parameters of the main rib, namely the angle θ, width L and height H, as well as the values ​​of the curved surface depression radius, inner and outer fillet radius and rubber coating thickness set on the side of the main rib, and structurally designing the rubber body, outer sleeve and inner core of the rubber suspension main spring.

3. The optimization design method of the rubber suspension main spring according to claim 1 is characterized in that: In step (a), the finite element analysis of the three-dimensional static stiffness of the rubber suspension main spring includes: 1) simplifying the rubber suspension main spring, removing the limit blocks in the U direction and the W direction, and retaining only the rubber main ribs and the fillet part; importing the simplified rubber suspension main spring model into the HyperMesh software in the STP file format, and constructing the finite element model of the rubber suspension main spring by using hexahedral mesh division; 2) MR constitutive model: The MR constitutive model is used to describe the mechanical behavior of the rubber body. The model formula is: W=C 10 (I1-3)+C 01 (I2-3) Where: C10, C01 are constitutive model parameters; C10 and C01 are related to the hardness of the rubber material. When the rubber hardness is 43HA, C10 = 0.00636, C01 = 0.2444, and the constitutive model parameters are assigned to the finite element model; 3) The unit nodes on the inner ring surface of the rubber main spring are coupled with the elastic center point, a radial displacement load of 1 mm is applied to the outer ring surface of the rubber main spring, and the six degrees of freedom of the outer surface of the rubber suspension are constrained; at the elastic center point, a displacement load of 3 mm is applied to the rubber suspension in the U, V, and W directions respectively; 4) In the post-processing part, the correlation values ​​of the reaction force and displacement of the elastic center point of the simplified model are obtained, the reaction force value corresponding to the displacement of 0-2mm is extracted, and the linear stiffness curve of the suspension in all directions is plotted according to the extracted value. The slope of the curve is the linear stiffness value of the rubber suspension in all directions.

4. The optimization design method of the rubber suspension main spring according to claim 2 is characterized in that: The structural parameters of the main ribs of the rubber suspension main spring include an angle θ, a width L and a height H, wherein the angle θ is 45° to 60°, the width L is 8 to 12 mm, and the height H is 15 to 20 mm; the curved concave radius of the side of the main rib is 1 to 2 mm, the inner and outer chamfer radii are R1.5 to 2 mm, and the rubber coating thickness is 1 to 2 mm.

5. A rubber suspension main spring, characterized in that: It is obtained by adopting the optimization design method described in any one of claims 1 to 4.

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