A method for finite element modeling and simulation of connection relationship of a steering system based on NVHD

Abstract

The application relates to a kind of NVHD-based steering system connection relationship finite element modeling simulation methods, including respectively establishing the finite element model of steering gear and connection relationship, the finite element model of steering intermediate shaft and connection relationship, the finite element model of steering column and connection relationship, the finite element model of steering wheel and connection relationship;The model is assembled;Modal verification is carried out to the assembled steering system model;The finite element model of steering system is assembled into the whole vehicle model.The application realizes the comprehensive and accurate modeling of the steering system in the whole vehicle model by considering the gear-rack transmission relationship, friction pair, spline, cross axle universal joint and other connection relationships of the steering system composed of steering machine, steering intermediate shaft, steering column and steering wheel in the whole vehicle model;Four-point MPC method is used to simulate gear-rack transmission, a more simple and reliable universal joint modeling method is adopted, and the accuracy and efficiency of the simulation prediction of whole vehicle steering wheel vibration and in-vehicle noise are improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive vibration and noise modeling and simulation technology, specifically involving a finite element modeling and simulation method for the connection relationship of a steering system based on NVHD. Background Technology

[0002] Today, vehicle quality is receiving increasing attention, with NVH performance being one of the key indicators determining vehicle quality. Establishing a whole-vehicle NVH simulation model is one of the most crucial methods for predicting vehicle vibration and noise performance. The kinematic pairs and connections of the steering system are complex, and the accuracy and precision of its modeling have a significant impact on the simulation calculation results of steering wheel vibration and in-vehicle noise.

[0003] Current modeling techniques for steering systems primarily focus on universal joint modeling, without providing detailed and systematic explanations of the modeling methods for the various connections within the steering system. Furthermore, they do not address modeling methods for steering systems used in noise and vibration analysis under NVHD conditions. In NVHD environments, improving the computational efficiency and prediction accuracy for vehicle steering wheel vibration and in-vehicle noise through simplified steering system connections and systematic finite element modeling and simulation is a pressing issue that needs to be addressed. Summary of the Invention

[0004] The purpose of this invention is to provide a finite element modeling and simulation method for steering system connection relationships based on NVHD. By systematically modeling the various connection relationships of the steering system and simplifying the modeling of the universal joint, the load transmission characteristics of the steering system in the whole vehicle model are more consistent with reality, thereby solving the problem of improving the accuracy and efficiency of whole vehicle vibration and noise simulation analysis.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A finite element modeling and simulation method for the connection relationships of a steering system based on NVHD, characterized by the following steps:

[0007] S1. Establish the finite element model and connection relationship of the steering gear, the steering intermediate shaft, the steering column, and the steering wheel respectively.

[0008] S2. Assemble the model created in step S1 in NVHD;

[0009] S3. Perform modal verification on the steering system model assembled in step S2;

[0010] S4. Assemble the finite element model of the steering system into the vehicle model.

[0011] Further, in step S1, the finite element model of the steering gear includes a steering tie rod 1-1, a steering rack 1-2, a steering gear 1-3, a steering gear housing 1-4, and a lower outer fork 1-5; wherein, the steering tie rod 1-1 and the steering rack 1-2 are connected by a ball joint 1-6; the steering rack 1-2 and the steering gear 1-3 are connected by a four-point MPC transmission; the steering gear 1-3 and the steering gear housing 1-4 are connected by an axial rotational connection; the steering gear 1-3 and the lower outer fork 1-5 are connected by a spline connection; and the steering rack 1-2 and the steering gear housing 1-4 are connected by an axial movement connection, and a friction pair is established to simulate the translational damping characteristics.

[0012] Furthermore, by establishing a four-point MPC simulation of the gear and rack transmission relationship, the specific steps are as follows:

[0013] S11. Establish a local coordinate system 1-11 with the axial direction of the shaft 1-3 where the steering gear is located as the z-direction;

[0014] S12. Establish nodes A, B, C, and D, where point A is on steering gear 1-3, points B and D are on steering housing 1-4, point C is on steering rack 1-2, points A and B are located on the steering gear axis and assigned a local coordinate system 1-11, and points C and D are located on the steering rack axis and use the vehicle coordinate system 1-12.

[0015] S13. Create a four-point MPC based on nodes A, B, C, and D. Points A and B are given 6 degrees of freedom, and points C and D are given 2 degrees of freedom. The gear and rack transmission relationship formula is: x(AB) + y(CD) = 0, where x and y are the transmission ratios, which need to be input according to the actual situation to realize the steering wheel rotation in y radians and the rack movement in x millimeters.

[0016] Further, in step S1, the finite element model of the steering intermediate shaft includes an upper inner fork 2-1, an upper shaft 2-2, a lower shaft 2-3, and a lower inner fork 2-4; wherein, the upper inner fork 2-1 and the upper shaft 2-2 are connected by a spline 2-5; the upper shaft 2-2 and the lower shaft 2-3 are connected by a spline 2-6; and the lower shaft 2-3 and the lower inner fork 2-4 are connected by a spline 2-7.

[0017] Further, in step S1, the finite element model of the steering column includes an upper steering column shaft 3-1, a steering column housing 3-2, a lower steering column shaft 3-3, and an upper outer fork 3-4; wherein, the upper steering column shaft 3-1 and the lower steering column shaft 3-3 are connected by a spline 3-5; the upper and lower steering column shafts are axially rotated to the steering column housing 3-2; and the lower steering column shaft 3-3 and the upper outer fork 3-4 are connected by a spline 3-6.

[0018] Further, in step S1, SW, SW3, SW6, SW9, and SW12 in the finite element model of the steering wheel are response points. The response points need to be assigned a local coordinate system 4-1. The coordinate system 4-1 is z-direction along the normal direction of the steering wheel plane, x-direction along the SW-SW6 direction, and y-direction along the SW-SW3 direction.

[0019] Further, step S2 specifically involves: establishing a universal joint between the steering gear finite element model and the steering intermediate shaft finite element model, establishing a universal joint between the steering intermediate shaft finite element model and the steering column finite element model, and establishing a spline between the steering column finite element model and the steering wheel finite element model.

[0020] Furthermore, the lower inner fork 2-4 and the lower outer fork 1-5 are connected by a universal joint 5-1; the upper inner fork 2-1 and the upper outer fork 3-4 are connected by a universal joint 5-2; and the upper shaft 3-1 of the steering column and the steering wheel 4 are connected by a spline 5-3.

[0021] Furthermore, the specific steps for establishing a universal joint are as follows:

[0022] Step S21: Establish a local coordinate system 2-10. The axis where the lower outer fork 1-5 is located is the z-direction of coordinate system 2-8, and the axis where the lower inner fork 2-4 is located is the z-direction of coordinate system 2-9. The perpendicular direction of the angle bisector of the z-direction of coordinate systems 2-8 and 2-9 is the z-direction of local coordinate system 2-10.

[0023] Step S22: Establish CBUSH at the hard point of the universal joint and assign a local coordinate system 2-10. The stiffness of degrees of freedom 1236 is relatively large, while the stiffness of degree of freedom 45 is relatively small or 0.

[0024] Further, in step S4, the modal verification is a modal simulation analysis of the steering system to confirm that the above-mentioned connection and transmission relationships of the steering system are accurate and reliable, especially the gear and rack transmission relationship and the universal joint connection relationship.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. This invention achieves comprehensive and accurate modeling of the steering system in the vehicle model by considering the gear-rack transmission relationship, friction pairs, splines, universal joints, and other connection relationships of the steering system, which consists of the steering gear, steering intermediate shaft, steering column, and steering wheel.

[0027] 2. By establishing a finite element model and kinematic pairs of the steering system in HyperMesh, establishing the connection relationship between each sub-model in NVHD, simulating gear and rack transmission using the four-point MPC (Multi-point constraints) method, and adopting a simpler and more reliable universal joint modeling method, the accuracy and efficiency of simulation prediction of vehicle steering wheel vibration and in-vehicle noise are improved. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of a finite element modeling and assembly method for the connection relationship of an automotive steering system based on NVHD, according to one embodiment of the present invention.

[0030] Figure 2 This is a flowchart of the finite element modeling method for the steering gear according to one embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of a four-point MPC modeling method in a steering gear according to one embodiment of the present invention;

[0032] Figure 4 This is a flowchart of the finite element modeling method for the steering intermediate shaft in one embodiment of the present invention;

[0033] Figure 5 This is a flowchart of the finite element modeling method for the steering column according to one embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of a steering wheel modeling method according to one embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of a cross-shaped universal joint modeling method according to one embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments:

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0038] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] This invention relates to a finite element modeling and simulation method for the connection relationships of a steering system based on NVHD, comprising the following steps:

[0040] 1. Establish a finite element model of the steering gear;

[0041] 2. Establish a finite element model of the steering intermediate shaft;

[0042] 3. Establish a finite element model of the steering column;

[0043] 4. Establish a finite element model of the steering wheel;

[0044] 5. Steering system model assembly;

[0045] 6. Modal verification;

[0046] 7. Assembly of the complete vehicle model.

[0047] The finite element model 1 of the steering gear includes a steering tie rod 1-1, a steering rack 1-2, a steering gear 1-3, a steering gear housing 1-4, and a lower outer fork 1-5. The steering tie rod 1-1 and the steering rack 1-2 are connected by a ball joint 1-6. The transmission relationship between the steering rack 1-2 and the steering gear 1-3 is simulated using a four-point MPC 1-7. A local coordinate system 1-11 needs to be established for the four-point MPC 1-7. Axial rotation 1-8 is allowed between the steering gear 1-3 and the steering gear housing 1-4. A local coordinate system 1-11 needs to be established for the axial rotation 1-8. The steering gear 1-3 and the lower outer fork 1-5 are connected by a spline 1-9. Axial movement 1-10 is allowed between the steering rack 1-2 and the steering gear housing 1-4, and a friction pair is established.

[0048] The finite element model 2 of the steering intermediate shaft includes an upper inner fork 2-1, an upper shaft 2-2, a lower shaft 2-3, and a lower inner fork 2-4. The upper inner fork 2-1 and the upper shaft 2-2 are connected by a spline 2-5. The upper shaft 2-2 and the lower shaft 2-3 are connected by a spline 2-6. A local coordinate system needs to be established for spline 2-6. The lower shaft 2-3 and the lower inner fork 2-4 are connected by a spline 2-7.

[0049] The finite element model 3 of the steering column includes an upper steering column shaft 3-1, a steering column housing 3-2, a lower steering column shaft 3-3, and an upper outer fork 3-4. The upper steering column shaft 3-1 and the lower steering column shaft 3-3 are connected by a spline 3-5. A local coordinate system 2-9 needs to be established for the spline 3-5. Axial rotation 3-7 is allowed between the upper and lower steering column shafts and the steering column housing 3-2. A local coordinate system 2-9 is established for the axial rotation 3-7. The lower steering column shaft 3-3 and the upper outer fork 3-4 are connected by a spline 3-6.

[0050] In the steering wheel model 4, SW3, SW6, SW9, and SW12 are response points. The response points need to be assigned a local coordinate system 4-1. The coordinate system 4-1 is z-direction along the normal direction of the steering wheel plane, x-direction along the SW-SW6 direction, and y-direction along the SW-SW3 direction.

[0051] The steering system model is assembled by establishing connections between the steering gear finite element model, the steering intermediate shaft finite element model, the steering column finite element model, and the steering wheel finite element model, and these connections are established in NVHD. The lower inner fork 2-4 and the lower outer fork 1-5 are connected by a universal joint 5-1. A local coordinate system 2-10 needs to be established for the universal joint 5-1. The upper inner fork 2-1 and the upper outer fork 3-4 are connected by a universal joint 5-2. A local coordinate system needs to be established for the universal joint 5-2. The upper shaft 3-1 of the steering column and the steering wheel 4 are connected by a spline 5-3.

[0052] Modal verification 6 is a modal simulation analysis of the steering system, confirming that the above-mentioned connection and transmission relationships of the steering system are accurate and reliable, especially the gear and rack transmission relationship and the universal joint connection relationship.

[0053] The vehicle model assembly 7 involves assembling the accurately modeled steering system with the various subsystems of the vehicle to establish a vehicle NVHD finite element model for vehicle vibration and noise simulation analysis.

[0054] Example 1

[0055] The automotive steering system mainly consists of the steering gear, steering intermediate shaft, steering column, and steering wheel. The above models and their internal connections are established in HyperMesh, while the connections between sub-models are established in NVHD. These are then used for vehicle assembly and vibration and noise simulation analysis.

[0056] like Figure 1As shown, this invention systematically models and modally verifies the connection relationships of the automotive steering system, obtaining a more accurate and reliable finite element model of the steering system based on NVHD, thereby improving the simulation accuracy of vehicle vibration and noise. By establishing a four-point MPC to simulate the gear and rack transmission relationship, and by establishing CBUSH and a local coordinate system to simulate the universal joint, the direction of the rotational torque is changed at a constant speed. This connection method is simple, accurate, and effective in modeling, and can precisely simulate the motion relationships of the steering system.

[0057] The present invention provides a finite element modeling and simulation method for the connection relationship of the steering system based on NVHD, which includes the steps of establishing a finite element model of the steering gear, establishing a finite element model of the steering intermediate shaft, establishing a finite element model of the steering column, establishing a finite element model of the steering wheel, assembling the steering system model, modal verification, and assembling the whole vehicle model.

[0058] like Figure 2 As shown, the finite element model of the steering gear includes a steering tie rod 1-1, a steering rack 1-2, a steering gear 1-3, a steering gear housing 1-4, and a lower outer fork 1-5.

[0059] The steering tie rod 1-1 and the steering rack 1-2 are connected by a ball joint 1-6, and the modeling method is RBE2(123).

[0060] The transmission relationship between the steering rack 1-2 and the steering gear 1-3 is simulated by four points MPC1-7, and the four points MPC1-7 need to establish a local coordinate system 1-11.

[0061] The axial rotation 1-8 between the steering gear 1-3 and the steering housing 1-4 is modeled as RBE2(12345). The axial rotation 1-8 requires the establishment of a local coordinate system 1-11, with the z-direction along the axial direction. The local coordinate system 1-11 is assigned to the master node of RBE2 to realize the simulation of the gear axial rotation.

[0062] The steering gear 1-3 and the lower outer fork 1-5 are connected by spline 1-9, and the modeling method is RBE2(123456).

[0063] The steering rack 1-2 and the steering gear housing 1-4 are allowed to move axially by 1-10, using the vehicle coordinate system and modeling method RBE2(13456). In particular, the translational damping characteristics of the friction pair should be established, modeled using CBUSH, and stiffness and damping should be assigned according to the actual situation to realize the translational simulation of the rack.

[0064] like Figure 3 As shown, the function of the steering gear is to convert the rotational displacement of the steering wheel into the lateral rotation of the rack through the reversing gear. The transmission relationship of the gear and rack is simulated by establishing a four-point MPC, and the specific steps are as follows:

[0065] Step 1: Establish a local coordinate system 1-11 with the axial direction of the shaft 1-3 where the steering gear is located as the z-direction;

[0066] Step 2: Establish nodes A, B, C, and D. Point A is on steering gear 1-3, points B and D are on steering housing 1-4, and point C is on steering rack 1-2. In particular, points A and B are located on the steering gear axis and assigned a local coordinate system 1-11, while points C and D are located on the steering rack axis and use the vehicle coordinate system 1-12.

[0067] Step 3: Create a four-point MPC based on nodes A, B, C, and D. Points A and B are given 6 degrees of freedom, and points C and D are given 2 degrees of freedom. The gear and rack transmission relationship formula is: x(AB) + y(CD) = 0, where x and y are the transmission ratios, which need to be input according to the actual situation to realize the steering wheel rotation of y radians and the rack movement of x millimeters.

[0068] like Figure 4 As shown, the finite element model of the steering intermediate shaft includes an upper inner fork 2-1, an upper shaft 2-2, a lower shaft 2-3, and a lower inner fork 2-4.

[0069] The upper inner fork 2-1 and the upper shaft 2-2 are connected by spline 2-5, and the modeling method is RBE2(123456).

[0070] The upper shaft 2-2 and the lower shaft 2-3 are connected by a spline 2-6. The spline 2-6 needs to establish a local coordinate system with the z-direction along the axial direction and the modeling method is RBE2(12456).

[0071] The lower shaft 2-3 and the lower inner fork 2-4 are connected by spline 2-7, and the modeling method is RBE2(123456).

[0072] like Figure 5 As shown, the finite element model of the steering column includes the upper steering column shaft 3-1, the steering column housing 3-2, the lower steering column shaft 3-3, and the upper outer fork 3-4.

[0073] The upper shaft 3-1 and the lower shaft 3-3 of the steering column are connected by a spline 3-5. The spline 3-5 needs to establish a local coordinate system 2-9, with the z-direction along the axial direction, and the modeling method is RBE2(12456).

[0074] The upper and lower axes of the steering column are allowed to rotate axially 3-7 with respect to the steering column housing 3-2. The axial rotation 3-7 establishes a local coordinate system 2-9, with the axial direction being z-axis, and the modeling method is RBE2(12345).

[0075] The lower shaft 3-3 of the steering column and the upper outer fork 3-4 are connected by a spline 3-6, and the modeling method is RBE2(123456).

[0076] like Figure 6 As shown, in the finite element model of the steering wheel, SW, SW3, SW6, SW9, and SW12 are response points. The response points need to be assigned a local coordinate system 4-1. The coordinate system 4-1 is z-direction along the normal direction of the steering wheel plane, x-direction along the SW-SW6 direction, and y-direction along the SW-SW3 direction.

[0077] The steering system model is assembled by establishing a connection between the steering gear finite element model, the steering intermediate shaft finite element model, the steering column finite element model, and the steering wheel finite element model.

[0078] The lower inner fork 2-4 and the lower outer fork 1-5 are connected by a cross-shaped universal joint 5-1, and the cross-shaped universal joint 5-1 needs to establish a local coordinate system 2-10.

[0079] The upper inner fork 2-1 and the upper outer fork 3-4 are connected by a cross-shaped universal joint 5-2, and the cross-shaped universal joint 5-2 needs to establish a local coordinate system.

[0080] The upper shaft 3-1 of the steering column is connected to the steering wheel 4 by spline 5-3, and the modeling method is RBE2(123456).

[0081] like Figure 7 As shown, the universal joint can change the direction of the steering torque at a constant speed. By establishing a universal joint in NVHD, the kinematic relationship between the steering gear and the steering intermediate shaft, and between the steering intermediate shaft and the steering column can be simulated. This modeling method is simple to operate and can provide accurate and reliable universal joint connection relationships for the analysis of vehicle steering wheel vibration and in-vehicle noise. The specific steps are as follows:

[0082] Step 1: Establish a local coordinate system 2-10. The axis where the lower outer fork 1-5 is located is the z-direction of coordinate system 2-8, and the axis where the lower inner fork 2-4 is located is the z-direction of coordinate system 2-9. The perpendicular direction of the angle bisector of the z-direction of coordinate systems 2-8 and 2-9 is the z-direction of local coordinate system 2-10.

[0083] Step 2: Establish CBUSH at the hard point of the universal joint and assign a local coordinate system 2-10. In particular, the stiffness of degrees of freedom 1236 is relatively large, while the stiffness of degree of freedom 45 is relatively small or 0.

[0084] The modal verification is a modal simulation analysis of the steering system, which confirms that the above-mentioned connection and transmission relationships of the steering system are accurate and reliable, especially the gear and rack transmission relationship and the universal joint connection relationship.

[0085] The vehicle model assembly involves assembling the accurately modeled steering system with the various subsystems of the vehicle to establish a vehicle NVHD finite element model for vehicle vibration and noise simulation analysis.

[0086] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A finite element modeling and simulation method for the connection relationship of a steering system based on NVHD, characterized in that, Includes the following steps: S1. Establish the finite element model and connection relationship of the steering gear, the steering intermediate shaft, the steering column, and the steering wheel respectively. S2. Assemble the model created in step S1 in NVHD; S3. Perform modal verification on the steering system model assembled in step S2; S4. Assemble the finite element model of the steering system into the vehicle model; Step S1: The finite element model of the steering gear includes a steering tie rod (1-1), a steering rack (1-2), a steering gear (1-3), a steering gear housing (1-4), and a lower outer fork (1-5); wherein, the steering tie rod (1-1) and the steering rack (1-2) are connected by a ball joint (1-6); the steering rack (1-2) and the steering gear (1-3) are connected by a four-point MPC transmission; the steering gear (1-3) and the steering gear housing (1-4) are connected by an axial rotational connection; the steering gear (1-3) and the lower outer fork (1-5) are connected by a spline connection; the steering rack (1-2) and the steering gear housing (1-4) are connected by an axial movement connection, and a friction pair is established to simulate the translational damping characteristics; The transmission relationship of the gear and rack is simulated by establishing a four-point MPC. The specific steps are as follows: S11. Establish a local coordinate system (1-11) with the axial direction of the shaft (1-3) where the steering gear is located as the z-direction. S12. Establish nodes A, B, C, and D, where point A is on the steering gear (1-3), points B and D are on the steering gear housing (1-4), point C is on the steering rack (1-2), points A and B are located on the steering gear axis and assigned a local coordinate system (1-11), and points C and D are located on the steering rack axis and use the vehicle coordinate system (1-12). S13. Create a four-point MPC based on nodes A, B, C, and D. Points A and B are given 6 degrees of freedom, and points C and D are given 2 degrees of freedom. The gear and rack transmission relationship formula is: x(AB)+y(CD)=0, where x and y are the transmission ratios, which need to be input according to the actual situation to realize the steering wheel rotation of y radians and the rack movement of x millimeters.

2. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 1, characterized in that: Step S1, the finite element model of the steering intermediate shaft includes an upper inner fork (2-1), an upper shaft (2-2), a lower shaft (2-3), and a lower inner fork (2-4); wherein, the upper inner fork (2-1) and the upper shaft (2-2) are connected by a spline (2-5); the upper shaft (2-2) and the lower shaft (2-3) are connected by a spline (2-6); and the lower shaft (2-3) and the lower inner fork (2-4) are connected by a spline (2-7).

3. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 1, characterized in that: Step S1, the finite element model of the steering column includes an upper steering column shaft (3-1), a steering column housing (3-2), a lower steering column shaft (3-3), and an upper outer fork (3-4); wherein, the upper steering column shaft (3-1) and the lower steering column shaft (3-3) are connected by a spline (3-5); the upper and lower steering column shafts are axially rotated to the steering column housing (3-2); and the lower steering column shaft (3-3) and the upper outer fork (3-4) are connected by a spline (3-6).

4. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 1, characterized in that: Step S1: In the finite element model of the steering wheel, SW, SW3, SW6, SW9, and SW12 are response points. The response points need to be assigned a local coordinate system (4-1). The coordinate system (4-1) is z-direction along the normal direction of the steering wheel plane, x-direction along the SW-SW6 direction, and y-direction along the SW-SW3 direction.

5. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 1, characterized in that, Step S2 specifically involves: establishing a universal joint between the steering gear finite element model and the steering intermediate shaft finite element model, establishing a universal joint between the steering intermediate shaft finite element model and the steering column finite element model, and establishing a spline between the steering column finite element model and the steering wheel finite element model.

6. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 5, characterized in that: The lower inner fork (2-4) and the lower outer fork (1-5) are connected by a cross-shaft universal joint (5-1); the upper inner fork (2-1) and the upper outer fork (3-4) are connected by a cross-shaft universal joint (5-2); the upper shaft of the steering column (3-1) and the steering wheel (4) are connected by a spline (5-3).

7. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 5, characterized in that, The specific steps for establishing a universal joint are as follows: Step S21: Establish a local coordinate system (2-10). The axis where the lower outer fork (1-5) is located is the z-direction of coordinate system (2-8), the axis where the lower inner fork (2-4) is located is the z-direction of coordinate system (2-9), and the perpendicular direction of the angle bisector of the z-direction of coordinate system (2-8) and coordinate system (2-9) is the z-direction of local coordinate system (2-10). Step S22: Establish CBUSH at the hard point of the universal joint and assign a local coordinate system (2-10). The stiffness of degrees of freedom 1236 is relatively large, while the stiffness of degree of freedom 45 is relatively small or 0.

8. The finite element modeling and simulation method for the connection relationship of a steering system based on NVHD according to claim 1, characterized in that: Step S4, the modal verification is the modal simulation analysis of the steering system, confirming that the above-mentioned connection and transmission relationships of the steering system are accurate and reliable, especially the gear and rack transmission relationship and the universal joint connection relationship.

Images