CN101367323A - Design method for air spring rubber air chamber for automobile - Google Patents

Abstract

The invention discloses a method for designing a rubber air chamber for an air spring of a vehicle. The method comprises the following steps: firstly, three geometric parameters of the radius of a central contour, the radius of a tangential point of a radial section and the cord bias angle of the central contour are calculated according to the bearing capacity and the elasticity of the air spring; secondly, the balanced profile of the rubber air chamber is drawn; thirdly, a three-dimensional model is established for the profile and a nonlinear three-dimensional finite element model of the air spring is established by the finite element method; and fourthly, optimized design of the rubber air chamber of the air spring system is completed by taking the minimum strain energy density of the rubber air chamber as an objective function. Database of the method can be updated continuously along with occurrence of a novel air spring and design completion of a novel air suspension system; and the method can meet the demands of design of the whole vehicle such as evenness, operation stability, riding comfort and so on and can guarantee that the air spring can meet the demands of the running performance of the vehicle.

Description

A kind of method of designing of air spring rubber air chamber for automobile

Technical field

The present invention relates to a kind of air spring for automobile design of main parts method, be specifically related to a kind of adaptation design method of air spring rubber air chamber for automobile.

Background technology

Along with the fast development of the domestic express highway of China and improving constantly of numerous people living standard, the travelling comfort of vehicle is had higher requirement.Air suspension compare with the steel spring suspension have non-linear rigidity, advantage such as the natural frequency of vibration is low and the high-frequency vibration isolation performance is good, the Vehicular air suspension has become the research focus of car manufactures and researcher.Air suspension mainly is made up of systems such as air bellow, shock absorber and guiding mechanisms, and air bellow is the carrying of air suspension and the key element of vibration damping, mainly is made up of rubber pneumatic bag, cover plate and piston.Air bellow and orthodox car suspension exist essential difference with the method for designing and the process of steel spring.Therefore traditional vehicle can't be applied to air bellow with the method for designing of steel spring and process, researchs and develops a kind of air spring for automobile design system and will have crucial society and economic benefit.

Summary of the invention

The objective of the invention is provides a kind of method of designing of air spring rubber air chamber for automobile, to satisfy the needs of automobile industry development for overcoming the deficiency of traditional vehicle usefulness steel spring method of designing in the prior art.

The technical solution used in the present invention: comprise data bank, car load technical requirement on design, airsuspension system scheme, this method of designing as follows:

A, according to the car load technical requirement on design, determine the airsuspension system scheme by analyzing, and calculate the performance requriements of air spring assembly;

B, calculate in the rubber pneumatic bag according to air bellow bearing capacity, elastic behavior in contour radius, radially section point of contact radius and these three geometric parameters of middle contour angle of cord;

C, according in the contour radius, radially section point of contact radius and these three geometric parameters of middle contour angle of cord are drawn out rubber pneumatic bag balance profile;

D, the rubber pneumatic bag balance profile of drawing out is set up 3D modelling, and set up air bellow non-linear three-dimensional finite element model with finite element method with CAD software;

E, be objective function, with middle contour radius, radially section point of contact radius and these three geometric parameters of middle contour angle of cord are the optimal design that variable is finished the air spring system rubber pneumatic bag with the strain energy density minimum of rubber pneumatic bag.

The invention has the beneficial effects as follows: data bank of the present invention can be finished and bring in constant renewal in along with the appearance of new air bellow and new airsuspension system design.Can satisfy requirements such as car load design-calculated ride comfort, handling stability, travelling comfort, can guarantee that air bellow can satisfy the road holding requirement.

Description of drawings

The invention will be further described below in conjunction with the drawings and specific embodiments.

Fig. 1 is a design cycle block diagram of the present invention;

Fig. 2 is the contour design scheme drawing of rubber pneumatic bag of the present invention;

Fig. 3 is the cutaway view of rubber pneumatic bag among Fig. 2.

The specific embodiment

Referring to Fig. 1, system of the present invention comprises:

A car load technical requirement on design module 1.

The coupling design module 2 of an airsuspension system.According to the car load general design requirement, promptly ride comfort, handling stability, travelling comfort etc. require the preliminary airsuspension system scheme of determining car load, and this scheme mainly contains compositions such as air bellow, damping shock absorber, guiding mechanism, air-channel system.

Calculate the mechanical property requirements of car load respectively according to vehicle zero load, semi-load and fully loaded three kinds of load working conditions and road surface operating mode to air spring system, and input database 3, this data bank 3 comprises the car load data, the airsuspension system characteristic data, the performance data of each constituent elements, characteristic data, geometric data etc. in the airsuspension system, be used for supporting the design or the type selecting of airsuspension system, determine the airsuspension system scheme.This data bank can be finished and bring in constant renewal in along with the appearance of new air bellow and new airsuspension system design.

This shows that the present invention is by setting up car load math modeling, airsuspension system math modeling, with handling stability, ride comfort be target to the vehicle performance analysis, thereby improve the demand of car load to air suspension, determine final airsuspension system scheme.

Module 4 of the present invention is determined that tentatively the structure of air bellow is formed, and is calculated bearing capacity, the dynamic elasticity characteristic of air bellow by performance analysis according to aforesaid airsuspension system scheme.

System of the present invention also comprises air bellow structure design module 5.Contour radius in drawing in the rubber pneumatic bag according to computing formula, radially section point of contact radius and these three geometric parameters of middle contour angle of cord.

Specific design step of the present invention is:

A, according to the vehicle performance requirement, determine air suspension assembly scheme by analyzing, and calculate the performance requriements of air spring assembly.

Its method is: set up vehicle mathematical model, with ISO2631 standard traveling comfort, parse suspension rate and damping force characteristics requirement, again according to air suspension assembly scheme, parse the elastic behavior of air bellow.

B, air bellow structure design module 5 of the present invention calculate geometric parameter in the rubber pneumatic bag according to air bellow bearing capacity, elastic behavior, referring to Fig. 2.

Its method is: the relation that is fit to following equation between the geometric parameter of rubber pneumatic bag and the air bellow design conditions point performance perameter:

F＝πr ²(P _r+P _a)-2πrN _ψcosδ

${\mathrm{\β}}_k=\mathrm{arctg}\sqrt{N_{\mathrm{\θ},k}/N_{\mathrm{\ψ},k}}$

$K=n(P_r+P_a)\frac{A_{\mathrm{eff}}^2}{V_i}+(P_r+P_a)\frac{{2\mathrm{\&pi;C}}_1{C}_2}{(H-\frac{x_i}{2})}{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&beta;}({\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2{\mathrm{\&beta;}}_k+{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2{\mathrm{\&beta;}}_m-2{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&beta;})$

$+\frac{{4\mathrm{\&pi;E}}_{\mathrm{ef}}{h}_{\mathrm{ef}}r(1+{\mathrm{<figure-callout\; id="4"\; label="ctg"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">ctg</figure-callout>}}^4\mathrm{\&beta;}-{\mathrm{<figure-callout\; id="2"\; label="ctg"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">ctg</figure-callout>}}^2\mathrm{\&beta;})}{{(H-\frac{x_i}{2})}^2}$

In the formula: F---the vertical load that air bellow is suffered, ox;

P _r---air bellow internal gas pressure, handkerchief;

P _a---environment atmospheric pressure, handkerchief;

R---rubber pneumatic bag profile radius, rice;

δ---rubber pneumatic bag characteristic angle, degree;

N _ψ---rubber pneumatic bag fiber-reinforced rubber composite material strength, MPa;

N _{θ, k}---the peripheral force of contour place section in acting on, ox/rice;

N _{ψ, k}---the diametral load of contour place section in acting on, ox/rice;

The elastic stiffness of K---air bellow, MPa;

A _Eff---air bellow effective bearing area, sq m;

V _i---air bellow internal capacity, cubic meter;

N---gas poly-trope index;

C ₁, C ₂---rubber pneumatic bag housing geometric configuration constant;

E _Ef---the elastic stiffness of airbag housing, MPa;

h _Ef---airbag housing equivalent thickness, rice;

x _i---the displacement in the air bellow forced stroke, rice;

H---air bellow balance position place operating altitude, rice;

β _k---middle contour angle of cord, degree;

β---rubber pneumatic bag is the angle of cord of any arbitrarily, degree.

In aforementioned relational expression, if F distributes to the maximum load of air bellow, (p for the automobile at full load _a+ P _r) for charging into the specified air pressure of air bellow in-to-in, N _ψThe intensity of getting the used fiber-reinforced rubber composite material of rubber pneumatic bag is divided by safety factor, and when characteristic angle δ be 0 ° of middle contour radius r that can solve rubber pneumatic bag _k, can solve radially section point of contact radius r when characteristic angle δ is 90 ° _m

The structure design of C, air spring rubber air chamber

Its method is: the rubber pneumatic bag construction parameter (r that obtains according to aforesaid equation _k, r _m, β _k), the drafting rubber pneumatic bag balance profile of application following relationship formula.

$y={\&Integral;}_r^{r_k}\frac{(r^2-r_m^2)\&CenterDot;\sqrt{(r_k^2-{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">r</figure-callout>}}^2{\sin }^2{\mathrm{\&beta;}}_k)}\&CenterDot;\mathrm{dr}}{\sqrt{{(r_k^2-r_m^2)}^2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="r\; k"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">r</figure-callout>}}_k^{}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2{\mathrm{\&beta;}}_k-{(r^2-r_m^2)}^2(r_k^2-{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="A200810156419E00081.png"\; state="\{\{state\}\}">r</figure-callout>}}^2{\sin }^2{\mathrm{\&beta;}}_k)}}$

With the balance profile is that neutral surface adds one to two layer of cordline to the left and right, and inwall is the caulking gum layer, and skin is the anti-corrosive rubber layer.

The performance simulation analysis of D, air bellow

Its method is: with CAD software (computer drawing software) aforesaid design result is set up 3D modelling, and set up air bellow non-linear three-dimensional finite element model with finite element method, with corresponding elastomeric material model simulation rubber, total external characteristics in the method emulation air bellows such as cord, hydrostatic(al) unit simulation internal gas in rebar (structure analysis software) the simulation utricule; In addition by sensivity analysis, for next step optimal design provides the key Design variable and judges the quality that design variable is chosen.

The structure optimization of E, rubber pneumatic bag

Under the situation that satisfies the air bellow mechanical property, be objective function with the strain energy density minimum of rubber pneumatic bag, with (r _k, r _m, β _k) to wait construction parameter be the optimal design that variable is finished the air spring system rubber pneumatic bag.

System of the present invention also comprises:

An air bellow finite element analysis module 6 is based on the modeling tool and the simulation analysis of computing machine, sensivity analysis.

An air bellow finite element analysis module 7, introduce genetic algorithm, given constrained condition 9 times, the air bellow structure 5 that design obtains according to aforementioned stages, and selected optimization derivation algorithm and 10 pairs of schemes of optimization aim function are further optimized.

The departure point of described optimization is to design and develop the initial air spring structure that the aforementioned stages of process obtains.Can constitute the design framework 10 of selecting two aspects by air bellow calculation of parameter, structure design by first initial air bellow structure.

In design framework 5 scopes, can form the simulation analysis model 6 that can satisfy performance simulation analysis requirement.This simulation analysis model 6, model analysis process and structure optimization process have following three essential characteristics:

(A) pardon allows rubber pneumatic bag, cover plate and the piston model of different confidence levels and degree of ripeness to participate in performance simulation analysis 6 math modelings.

(B) modularization, the characteristic model after the renewal of permission air bellow structure is augmented in the data bank (3) with the form of standalone module.

(C) quantize, i.e. all models and simulation analysis and optimization proposition all has the expression form that mathematics quantizes.This is characterized by the performance simulation analysis result to optimization aim function 8 these quantization characteristic leaching process.This quantizes the discriminant criterion 11 of statement work as optimal design.Propose two kinds of basic optimization targets in the described method and quantize statement:

(A) the rubber pneumatic bag strain energy density minimum under given air spring system mechanical characteristic index restriction;

(B) satisfy a certain performance figure (such as elastic stiffness) optimum under the rubber pneumatic bag strain energy density restriction.

At last, in the performance simulation analysis, finish sensivity analysis in the post-processing, differentiate to optimize the quality of choosing of result's quality and design parameters and design independent variable.

Finish the Optimal Structure Designing of rubber pneumatic bag under the guidance according to the sensivity analysis result.

If the optimal design criterion is set up, then optimal design finishes, and optimal design result 10 is outputed to optimize last handling process 12; Otherwise, according to selected optimization optimizing algorithm, constraint condition 9 selected next design vector at optimal design, with this design vector is that independent variable forms new design framework 5, promptly form new air spring system basic scheme, design variable selection result, start next round performance analysis optimization circulation.

Claims (2)

1. the method for designing of an air spring rubber air chamber for automobile comprises data bank, car load technical requirement on design, airsuspension system scheme, it is characterized in that: this method of designing as follows:

A, according to the car load technical requirement on design, determine the airsuspension system scheme by analyzing, and calculate the performance requriements of air spring assembly;

B, calculate in the rubber pneumatic bag according to air bellow bearing capacity, elastic behavior in contour radius, radially section point of contact radius and these three geometric parameters of middle contour angle of cord;

C, according in the contour radius, radially section point of contact radius and these three geometric parameters of middle contour angle of cord are drawn out rubber pneumatic bag balance profile;

D, the rubber pneumatic bag balance profile of drawing out is set up 3D modelling, and set up air bellow non-linear three-dimensional finite element model with finite element method with CAD software;

E, be objective function, with middle contour radius, radially section point of contact radius and these three geometric parameters of middle contour angle of cord are the optimal design that variable is finished the air spring system rubber pneumatic bag with the strain energy density minimum of rubber pneumatic bag.

2. the method for designing of a kind of air spring rubber air chamber for automobile according to claim 1 is characterized in that: steps A is the performance requriements that calculates air spring assembly according to vehicle zero load, semi-load and fully loaded three kinds of load working conditions and road surface operating mode respectively.

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