Steering rack fixing clamp and suspension elastic kinematics characteristic decomposition method

Abstract

This invention provides a steering rack fixing fixture and a method for decomposing the elastic kinematic characteristics of a suspension, comprising the following steps: fixing the vehicle body on a test platform, the test platform being equipped with a steering system; applying input forces F1, F2, F3, F4, F5, F6, and F7 to the wheel ends respectively, and obtaining wheel alignment changes D1, D2, D3, D4, D5, D6, and D7 respectively. The beneficial effects of this invention are: this method is suitable for testing the elastic kinematic characteristics of suspension in a complete vehicle state, and can be extended on a KC test bench. Through working condition settings and fixture design, the contributions of the suspension system assembly, steering gear assembly, steering column assembly, and power steering system to the elastic kinematic characteristics are decomposed; testing is performed in a complete vehicle state without disassembling the suspension system and steering system, resulting in high work efficiency.

Description

Technical Field

[0001] This invention belongs to the field of automotive chassis performance benchmarking testing and development, and in particular relates to a steering rack fixing fixture and a method for decomposing the elastic kinematic characteristics of suspension. Background Technology

[0002] During chassis design and development, it is necessary to benchmark and test the elastic kinematic characteristics of the chassis system (the changes in positioning parameters when the suspension is subjected to longitudinal forces, lateral forces, or self-centering torque). Compared to a non-steering independent rear suspension, the left and right sides of the front suspension are interconnected through the steering system. The deformation of the steering system is coupled into the elastic kinematic characteristics. Therefore, decomposing the characteristics of the suspension and steering systems to guide the design of each system is of paramount importance. This patent, through the design of test conditions and fixtures, can decompose the contributions of the suspension system assembly, steering gear assembly, steering column assembly, and power steering system to the elastic kinematic characteristics, providing a benchmark reference for system design. Summary of the Invention

[0003] In view of this, the present invention aims to provide a method for decomposing the elastic kinematic characteristics of a steering rack fixing fixture and a suspension, so as to provide a method for decomposing the contribution of the suspension system assembly, steering gear assembly, steering column assembly and steering assist system to the elastic kinematic characteristics.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A method for decomposing the elastic kinematic properties of a steering rack fixing clamp and a suspension includes the following steps:

[0006] S1. Secure the vehicle body to the test platform, which is equipped with a steering system;

[0007] S2. Turn off electric power steering, fix the steering wheel, apply input force F1 to the wheel end, and obtain the wheel alignment change D1.

[0008] S3. Turn off electric power steering, fix the steering wheel, apply input force F2 to the wheel end, and obtain the wheel alignment change D2.

[0009] S4. Turn on electric power steering, fix the steering wheel, apply input force F3 to the wheel end, and obtain the wheel alignment change D3.

[0010] S5. Turn off electric power steering, install fixing clamps on both sides of the steering gear to fix the steering wheel, apply input force F4 to the wheel end, and obtain the wheel alignment change D4.

[0011] S6. Turn off electric power steering, install clamps on both sides of the steering gear, fix the steering wheel, apply force F5 to the left wheel and do not apply force to the right wheel, and obtain the left wheel alignment change D5.

[0012] S7. Turn off electric power steering, install fixing clamps on both sides of the steering gear, apply input force F6 to the steering wheel end, and obtain the change in steering wheel angle D6.

[0013] S8. Turn on the electric power steering, install fixing clamps on both sides of the steering gear, apply input force F7 to the steering wheel end, and obtain the change in steering wheel angle D7.

[0014] Furthermore, the steering system in step S1 includes a steering column assembly, a steering gear, a steering rack, a steering tie rod, a suspension system, and a fixing clamp. One end of the steering column assembly is connected to the vehicle's steering wheel, and the other end of the steering column assembly is installed in the middle of the steering gear. The steering gear has a steering rack inside, and a fixing clamp is installed at each end of the steering gear. The two ends of the steering rack are nested inside the two fixing clamps, and the end of each fixing clamp away from the steering gear is connected to a suspension system through a steering tie rod.

[0015] Furthermore, the fixing fixture is a perforated truncated cone with a notch. The diameter of the hole in the fixing fixture is larger than the outer diameter of the steering rack. The outer diameter of the lower platform of the fixing fixture is larger than the outer diameter of the steering gear housing. The height of the fixing fixture is less than 1 / 2 of the stroke of the steering rack.

[0016] Furthermore, the deformation amount D1 in step S2 includes the deformation of the suspension system and the steering tie rod.

[0017] Furthermore, the deformation D2 in step S3 includes the deformation of the suspension system, steering tie rod, steering gear assembly, and steering column assembly.

[0018] Furthermore, the deformation amount D3 in step S4 includes the deformation of the suspension system, steering tie rod, steering gear assembly, steering column assembly, and the influence of the power steering system.

[0019] Furthermore, the deformation D4 in step S5 includes the deformation of the suspension system, steering tie rod, and steering gear assembly.

[0020] Furthermore, the deformation amount D5 in step S6 includes the deformation of the suspension system, steering tie rod and steering gear, and the value of deformation amount D5 is located between deformation amount D4 and deformation amount D1.

[0021] Furthermore, the deformation amount D6 in step S7 includes the deformation of the steering column assembly.

[0022] Furthermore, the deformation amount D7 in step S8 includes the deformation of the steering column assembly and the influence of power steering characteristics.

[0023] Compared with the prior art, the steering rack fixing clamp and suspension elastic kinematics decomposition method described in this invention have the following advantages:

[0024] (1) The present invention provides a steering rack fixing fixture and a method for decomposing the elastic kinematic characteristics of suspension. This method is suitable for testing the elastic kinematic characteristics of suspension under the condition of a whole vehicle. It can be extended on the KC test bench. By setting the working conditions and designing the fixture, the contribution of the suspension system assembly, steering gear assembly, steering column assembly and power assist system to the elastic kinematic characteristics can be decomposed.

[0025] (2) The steering rack fixing fixture and suspension elastic kinematics decomposition method described in this invention can be tested in the whole vehicle state without disassembling the suspension system and steering system, which is highly efficient. The rack and steering gear fixing fixture are easy to install, only the dust cover needs to be removed, without damaging the steering gear. Compared with the system-level bench test, the steering power system works normally in the whole vehicle state, without the need for additional power system operation auxiliary equipment. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 This is a schematic diagram of the steering system structure according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the normalizing torque loading condition described in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the longitudinal force loading condition described in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the lateral force loading condition described in an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Steering wheel; 2. Steering column assembly; 3. Steering gear; 4. Steering rack; 5. Steering tie rod; 6. Suspension system; 7. Fixture. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] like Figures 1 to 4 As shown, a method for decomposing the elastic kinematic properties of a steering rack fixing clamp and a suspension includes the following:

[0038] With the vehicle in its complete state, the vehicle body is fixed on the test platform. The vertical displacement of the platform is adjusted so that the left and right wheel loads meet the test requirements. (The test equipment has four columns supporting the four wheels of the vehicle. During the adjustment process described here, the four columns do not move vertically (the columns can be considered fixed to the ground). The "platform" clamps the vehicle body (in reality, it mostly clamps the lower edge of the vehicle body, which is the position where the jack is used when changing tires). In this way, the vehicle body and the "platform" can be considered connected together. When the "platform" moves downward, since the wheels do not move vertically, it will cause a change in the wheel load (the downward movement is the effect of the vehicle body being pressed down)).

[0039] Pre-fabricate the rack and steering gear fixing fixture 7. This fixture is a perforated truncated cone with a notch. The diameter of the hole is slightly larger than the diameter of the steering rack 4, the outer diameter of the lower platform is larger than the outer diameter of the steering gear 3 housing, and the height is slightly less than 1 / 2 of the steering rack 4's stroke. During installation, place the steering rack 4 in the middle position, remove the dust cover of the steering gear 3, and use the notch to place the truncated cone into both sides of the steering gear 3. Use shims to avoid gaps. After installation, the steering rack 4 and the steering gear 3 cannot have relative displacement and form a single unit.

[0040] The test content is as follows:

[0041] 1. Turn off electric power steering, fix steering wheel 1, and apply input force F1 (reverse return torque, reverse lateral force, or same-direction longitudinal force are input separately) to the wheel end. Here, F1 can be regarded as an array, and the corresponding D1 is also an array, representing the measured values ​​under different working conditions. Obtain the wheel alignment (x, y, z, Tx, Ty, Tz) change D1; where the deformation D1 includes the deformation of suspension system 6 and steering tie rod 5;

[0042] 2. Turn off electric power steering, fix steering wheel 1, and apply input force F2 (same-direction return torque, same-direction lateral force or opposite longitudinal force) to the wheel end to obtain the wheel alignment (x, y, z, Tx, Ty, Tz) change D2;

[0043] The deformation D2 includes the deformation of the suspension system 6, the steering tie rod 5, the steering gear assembly, and the steering column assembly;

[0044] 3. Turn on power steering, fix steering wheel 1, and apply input force F3 (same-direction return torque, same-direction lateral force or opposite longitudinal force) to the wheel end to obtain the wheel alignment (x, y, z, Tx, Ty, Tz) change D3;

[0045] Deformation D3 includes the deformation of the suspension system 6, steering tie rod 5, steering gear assembly 3, steering column assembly 2, and the influence of the power steering system;

[0046] 4. Turn off electric power steering, install fixing clamps 7 on both sides of the steering gear, fix the steering wheel 1, and apply input force F4 (same direction return torque, same direction lateral force or opposite longitudinal force) to the wheel end to obtain the wheel alignment (x, y, z, Tx, Ty, Tz) change D4.

[0047] The deformation D4 includes the deformation of the suspension system 6, the steering tie rod 5, and the steering gear assembly 3;

[0048] 5. Turn off electric power steering, install clamps 7 on both sides of the steering gear, fix the steering wheel 1, apply input force F5 (return torque, lateral force or longitudinal force) to the left wheel, and do not apply force to the right wheel to obtain the change in the left wheel's positioning (x, y, z, Tx, Ty, Tz) D5.

[0049] The deformation D5 includes the deformation of the suspension system 6, the steering tie rod 5, and the steering gear 3. D5 is between D4 and D1.

[0050] 6. Turn off electric power steering, install fixing clamps 7 on both sides of the steering gear, apply input force F6 (steering torque) to the steering wheel 1 end, and obtain the change in steering wheel angle D6;

[0051] The deformation D6 includes the deformation of the steering column assembly;

[0052] 7. Turn on the electric power steering, install the fixing clamps 7 on both sides of the steering gear, apply the input force F7 (steering torque) to the steering wheel 1 end, and obtain the change in steering wheel angle D7.

[0053] The deformation amount D7 includes the deformation of the steering column assembly and the influence of power steering characteristics.

[0054] During the test, the load amplitude and loading speed of F1, F2, F3, F4, and F5 were the same, while ensuring that the loading direction on the left (or right) side remained unchanged. The change in wheel alignment on the left (or right) side was used for data processing.

[0055] The contributions of each system to the change in elastic kinematics are as follows:

[0056] The contribution of the suspension system assembly and steering tie rod to the elastic kinematics is D1;

[0057] The contribution of the steering assembly to the elastic kinematics is D4-D1;

[0058] The contribution of the steering column assembly to the elastodynamics is D2-D4;

[0059] The contribution of electric power steering to flexural kinematics is D3-D2;

[0060] The steering column assembly contributes D6 to the positive load deformation of the steering system;

[0061] The steering assist characteristics contribute D7-D6 to the positive loading deformation of the steering system.

[0062] Advantages of this invention:

[0063] This method is suitable for testing the elastic kinematic characteristics of suspension in a complete vehicle state. It can be extended on the KC test bench. By setting the working conditions and designing the fixture, the contribution of the suspension system assembly, steering gear assembly, steering column assembly and power steering system to the elastic kinematic characteristics can be decomposed.

[0064] Testing can be conducted on the complete vehicle without disassembling the suspension and steering systems, resulting in high work efficiency.

[0065] The rack and steering gear fixing clamp 7 is easy to install; simply remove the dust cover without damaging the steering gear.

[0066] Compared to system-level bench testing, the power steering system works normally in the whole vehicle state, without the need for additional power steering system operation assistance equipment.

[0067] Example 1

[0068] Taking the return torque condition as an example, the contribution of each system to the change in wheel toe angle is decomposed as follows:

[0069] In the vehicle's complete state, the vehicle body is fixed on the test platform, and the vertical displacement of the platform is adjusted so that the left and right wheel loads meet the requirements of the half-load test.

[0070] With power steering off and steering wheel 1 fixed, a reverse return torque F1 with an amplitude of 100 Nm and a loading speed of 20 Nm / s is applied to the wheel end, and the change in wheel toe angle D1 is obtained as 6.042e-02deg.

[0071] With power steering off and steering wheel 1 fixed, apply a return torque F2 in the same direction to the wheel end with an amplitude of 100 Nm and an application speed of 20 Nm / s. The change in wheel toe angle D2 is 5.212e-01deg.

[0072] With power steering engaged and steering wheel 1 fixed, a return torque F3 is applied to the wheel end with an amplitude of 100 Nm and a loading speed of 20 Nm / s. The change in wheel toe angle D3 is 2.028e-01deg.

[0073] With power steering off, fixation clamps 7 are installed on both sides of the steering gear, and the steering wheel 1 is fixed. A return torque F4 is applied to the wheel end with an amplitude of 100 Nm and a loading speed of 20 Nm / s. The change in wheel toe angle D4 is 8.951e-02deg.

[0074] The contribution of the suspension system assembly and steering tie rod to the change in elastic kinematic toe angle is:

[0075] D1 = 6.042e-02deg.

[0076] The contribution of the steering assembly to the change in elastic kinematic toe angle is

[0077] D4-D1=8.951e-02-6.042e-02=2.909e-02deg.

[0078] The contribution of the steering column assembly to the change in toe angle in elastodynamics is:

[0079] D2-D4=5.212e-01-8.951e-02=4.317e-01deg.

[0080] The contribution of electric power steering to the change in toe angle in elastometry is:

[0081] D3-D2=2.028e-01-5.212e-01=-3.184e-01deg.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A steering rack fixture and suspension elastic kinematics decomposition method, characterized in that: Includes the following steps: S1. Secure the vehicle body to the test platform, which is equipped with a steering system; S2. Turn off electric power steering, fix the steering wheel (1), apply input force F1 to the wheel end, and obtain the wheel alignment change D1. S3. Turn off electric power steering, fix the steering wheel (1), apply input force F2 to the wheel end, and obtain the wheel alignment change D2. S4. Turn on electric power steering, fix the steering wheel (1), apply input force F3 to the wheel end, and obtain the wheel alignment change D3. S5. Turn off electric power steering, install fixing clamps (7) on both sides of the steering gear (3) to fix the steering wheel (1), apply input force F4 to the wheel end to obtain the wheel alignment change D4; S6. Turn off electric power steering, install clamps on both sides of the steering gear (3), fix the steering wheel (1), apply input force F5 to the left wheel and do not apply force to the right wheel, and obtain the left wheel positioning change D5. S7. Turn off electric power steering, install fixing clamps (7) on both sides of the steering gear (3), apply input force F6 to the steering wheel (1) end, and obtain the change in steering wheel (1) angle D6; S8. Turn on the electric power steering. Install the fixing clamps (7) on both sides of the steering gear (3). Apply input force F7 to the steering wheel (1) to obtain the change in steering wheel (1) angle D7. The steering system in step S1 includes a steering column assembly (2), a steering gear (3), a steering rack (4), a steering tie rod (5), a suspension system (6), and a fixing clamp (7). One end of the steering column assembly (2) is connected to the steering wheel (1) of the vehicle, and the other end of the steering column assembly (2) is installed in the middle of the steering gear (3). The steering gear (3) is provided with a steering rack (4). A fixing clamp (7) is installed at each end of the steering gear (3). The two ends of the steering rack (4) are nested into the two fixing clamps (7). The end of each fixing clamp (7) away from the steering gear (3) is connected to a suspension system (6) through a steering tie rod (5). The deformation D1 in step S2 includes the deformation of the suspension system (6) and the steering tie rod (5); The deformation D2 in step S3 includes the deformation of the suspension system (6), steering tie rod (5), steering gear (3) assembly and steering column assembly (2); The deformation D3 in step S4 includes the deformation of the suspension system (6), steering tie rod (5), steering gear (3) assembly, steering column assembly (2) and the influence of the power steering system; The deformation D4 in step S5 includes the deformation of the suspension system (6), the steering tie rod (5), and the steering gear (3) assembly; The deformation amount D5 in step S6 includes the deformation of the suspension system (6), the steering tie rod (5) and the steering gear (3), and the value of deformation amount D5 is between deformation amount D4 and deformation amount D1; The deformation amount D6 in step S7 includes the deformation of the steering column assembly (2); The deformation amount D7 in step S8 includes the deformation of the steering column assembly (2) and the influence of power steering characteristics.

2. The steering rack fixture and suspension elastic kinematics decomposition method of claim 1, wherein: The fixing clamp (7) is a perforated truncated cone with a notch. The diameter of the hole in the fixing clamp (7) is larger than the outer diameter of the steering rack (4). The outer diameter of the lower platform of the fixing clamp (7) is larger than the outer diameter of the housing of the steering gear (3). The height of the fixing clamp (7) is less than 1 / 2 of the stroke of the steering rack (4).

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