Calculation method of cab rubber suspension cushion stiffness

Abstract

The present invention relates to the technical field of cab suspension and vibration reduction systems for light commercial vehicles, and discloses a method for calculating the stiffness of a cab rubber suspension cushion, comprising the following steps: collecting parameters, including the weight and center of gravity of a base vehicle cab; estimating the weight G and center of gravity of a new vehicle cab based on the weight and center of gravity of the base vehicle cab and experience; calculating a single front suspension load F0; calculating a vibration number ratio λ of the suspension cushion; calculating an excitation frequency f of the suspension cushion = engine speed / 60*number of oscillations per cycle; and calculating a natural frequency f of the suspension cushion. n =f / λ; calculate the stiffness of the suspension cushion k = (2πf n ) 2 *F0. The cab rubber suspension cushion stiffness calculation method of the present invention can determine the performance parameters of the product during the research and development process to ensure satisfactory product performance.

Description

Technical Field

[0001] The present invention relates to the technical field of light commercial vehicle cab suspension vibration reduction systems, and in particular to a method for calculating the stiffness of a cab rubber suspension cushion. Background Art

[0002] At present, the stiffness matching of the cab suspension system generally adopts the decoupling method to calculate the stiffness of the suspension system, or determines the spring stiffness to improve comfort through multiple rounds of adjustments after the prototype vehicle is produced.

[0003] Among them, the decoupling method has relatively high requirements on the integrity of the cab 3D data. At the same time, since the cab is a non-rigid body and the passengers vary greatly, the decoupling is not sufficient, and there has been little in-depth research on the decoupling of the cab suspension system.

[0004] The method of tuning the prototype car requires tuning after the actual car is produced, which takes a relatively long time. As the current development cycle is constantly shortening, a simpler method is needed to shorten the development cycle and improve development efficiency. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned technology and provide a method for calculating the stiffness of the cab rubber suspension cushion, which can determine the performance parameters of the product during the research and development process and ensure that the product performance is satisfactory.

[0006] To achieve the above-mentioned object, the present invention relates to a method for calculating the stiffness of a cab rubber mount cushion, comprising the following steps:

[0007] A) Collect parameters, including the weight and center of gravity of the base vehicle cab;

[0008] B) Estimate the weight (G) and center of gravity of the new model cab based on the weight and center of gravity of the base model cab and experience;

[0009] C) Calculate the single front suspension load F0:

[0010] D) Calculate the vibration ratio λ of the suspension cushion;

[0011] E) Calculate the excitation frequency of the suspension cushion: f = engine speed / 60*number of oscillations per cycle;

[0012] F) Calculate the natural frequency f of the suspension cushion n =f / λ;

[0013] G) Calculate the stiffness of the suspension cushion k = (2πf n ) 2 *F0.

[0014] Preferably, the step A) further includes the stiffness K of the torsion bar for cab flipping, the maximum working angle θ of the torsion bar, the distance L between the flip center and the rear suspension center, and the maximum working angle θ of the torsion bar. c , the main driver's weight G 人 , the distance L between the driver's center of gravity and the rear suspension center c人 .

[0015] Preferably, in step B), the distance L between the center of gravity of the cab of the new vehicle model and the rollover center is obtained. g .

[0016] Preferably, in step C), the formula Kθ=G×L g +F 拉 ×L c Calculate the tension F of the rear suspension of the new model cab 拉 , let the force exerted by the driver on the front suspension be F 人 , take the rear suspension center as the balance point, and establish the moment balance: F 人 ×L c =G 人 ×L c人 , and find F 人 , then the single front suspension load F0=(G+F 人 +F 拉 ) / 2.

[0017] Preferably, in step D), Where i is the vibration isolation rate of the suspension pad.

[0018] Preferably, in step E), the engine speed is data obtained under idle condition.

[0019] Preferably, the vibration isolation rate i of the suspension cushion is ≥ 0.8.

[0020] Preferably, in step A), the collected parameters include the excitation frequency of the equipment in the cab of the new model. When the vibration number ratio λ is calculated for the first time, the vibration isolation rate i of the suspension cushion takes a value of 0.8. If the difference between the natural frequency of the suspension cushion obtained by the last calculation and the excitation frequency of the equipment in the cab of the new model is less than or equal to the resonance threshold, it is determined that the suspension cushion and the equipment in the cab of the new model will resonate, and the value of the vibration isolation rate i of the suspension cushion is increased until the difference between the natural frequency of the suspension cushion obtained by the last calculation and the excitation frequency of the equipment in the cab of the new model is greater than the resonance threshold.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. It can quickly match the cushion stiffness parameters, shorten the development time, and avoid making a large number of samples for adjustment;

[0023] 2. Forward design of the cab suspension cushion stiffness is performed using the vibration isolation rate method. Stiffness matching design can be performed without the need for complete 3D data. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to specific embodiments.

[0025] A method for calculating the stiffness of a cab rubber suspension cushion comprises the following steps:

[0026] A) Collect parameters, including the weight and center of gravity of the base model cab, as well as the stiffness K of the torsion bar used for cab flipping, the maximum operating angle θ of the torsion bar, and the distance L between the flip center and the rear suspension center. c , the main driver's weight G 人 , the distance L between the driver's center of gravity and the rear suspension center c人 ;

[0027] B) Based on the weight and center of gravity of the base model cab and experience, estimate the weight G and center of gravity of the new model cab, and obtain the distance L between the center of gravity and the rollover center of the new model cab. g ;

[0028] C) Calculate the single front suspension load F0 using the formula Kθ=G×L g +F 拉 ×L c Calculate the tension F of the rear suspension of the new model cab 拉 , let the force exerted by the driver on the front suspension be F 人 , take the rear suspension center as the balance point, and establish the moment balance: F 人 ×L c =G 人 ×L c人 , and find F 人 , then the single front suspension load F0=(G+F 人 +F 拉 ) / 2;

[0029] D) Calculate the vibration ratio λ of the suspension cushion, Where i is the vibration isolation rate of the suspension cushion;

[0030] E) Calculate the excitation frequency of the suspension cushion: f = engine speed / 60 * number of oscillations per cycle, where the engine speed is obtained at idle.

[0031] F) Calculate the natural frequency f of the suspension cushion n =f / λ;

[0032] G) Calculate the stiffness of the suspension cushion k = (2πf n ) 2*F0.

[0033] In the above embodiment, the vibration isolation rate i of the suspension cushion is ≥ 0.8. In addition, in step A), the collected parameters include the excitation frequency of the equipment in the cab of the new model. When the vibration number ratio λ is calculated for the first time, the vibration isolation rate i of the suspension cushion takes a value of 0.8. If the difference between the natural frequency of the suspension cushion obtained by the last calculation and the excitation frequency of the equipment in the cab of the new model is less than or equal to the resonance threshold, it is determined that the suspension cushion and the equipment in the cab of the new model will resonate, and the value of the vibration isolation rate i of the suspension cushion is increased until the difference between the natural frequency of the suspension cushion obtained by the last calculation and the excitation frequency of the equipment in the cab of the new model is greater than the resonance threshold.

[0034] The cab rubber suspension cushion stiffness calculation method of the present invention can quickly match cushion stiffness parameters, shorten development time, and avoid making a large number of samples for adjustment; the cab suspension cushion stiffness is designed forward in a vibration isolation rate manner, and stiffness matching design can be performed without the need for complete 3D data.

Claims

1. A method for calculating the stiffness of a cab rubber mount cushion, characterized by: The steps include: A) Collect parameters, including the weight and center of gravity of the base vehicle cab; B) Estimate the weight (G) and center of gravity of the new model cab based on the weight and center of gravity of the base model cab and experience; C) Calculate the single front suspension load F0: D) Calculate the vibration ratio λ of the suspension cushion; E) Calculate the excitation frequency of the suspension cushion: f = engine speed / 60*number of oscillations per cycle; F) Calculate the natural frequency f of the suspension cushion n =f / λ; G) Calculate the stiffness of the suspension cushion k = (2πf n ) 2 *F0.

2. The method for calculating the stiffness of the cab rubber mount cushion according to claim 1, characterized in that: The step A) also includes the stiffness K of the torsion bar used for cab flipping, the maximum working angle θ of the torsion bar, the distance L between the flip center and the rear suspension center, and the c , the main driver's weight G 人 , the distance L between the driver's center of gravity and the rear suspension center c人 .

3. The method for calculating the stiffness of the cab rubber mount cushion according to claim 2, characterized in that: In step B), the distance L between the center of gravity of the cab of the new vehicle model and the rollover center is obtained. g .

4. The method for calculating the stiffness of the cab rubber mount cushion according to claim 3, characterized in that: In step C), the formula Kθ=G×L g +F 拉 ×L c Calculate the tension F of the rear suspension of the new model cab 拉 , let the force exerted by the driver on the front suspension be F 人 , take the rear suspension center as the balance point, and establish the moment balance: F 人 ×L c =G 人 ×L c人 , and find F 人 , then the single front suspension load F0=(G+F 人 +F 拉 ) / 2.

5. The method for calculating the stiffness of the cab rubber mount cushion according to claim 4, characterized in that: In the step D), Where i is the vibration isolation rate of the suspension pad.

6. The method for calculating the stiffness of the cab rubber mount cushion according to claim 1, wherein: In step E), the engine speed is data obtained under idle condition.

7. The method for calculating the stiffness of the cab rubber mount cushion according to claim 5, characterized in that: The vibration isolation rate of the suspension cushion i≥0.

8.

8. The method for calculating the stiffness of the cab rubber mount cushion according to claim 7, characterized in that: In the step A), the collected parameters include the excitation frequency of the equipment in the cab of the new model. When the vibration number ratio λ is calculated for the first time, the vibration isolation rate i of the suspension cushion is taken as 0.

8. If the difference between the natural frequency of the suspension cushion obtained by the last calculation and the excitation frequency of the equipment in the cab of the new model is less than or equal to the resonance threshold, it is determined that the suspension cushion and the equipment in the cab of the new model will resonate, and the value of the vibration isolation rate i of the suspension cushion is increased until the difference between the natural frequency of the suspension cushion obtained by the last calculation and the excitation frequency of the equipment in the cab of the new model is greater than the resonance threshold.

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