Modeling method and device for double-tube shock absorber

Abstract

A modeling method and device for a twin-tube shock absorber relates to the technical field of shock absorbers. The method comprises: establishing simplified models of the twin-tube shock absorber's damping valve, one-way valve, oil compression process, and oil leakage process; establishing pressure-flow equations for the compression chamber, extension chamber, and oil storage chamber of the twin-tube shock absorber; and establishing a displacement equation for the twin-tube shock absorber's piston rod. Based on the simplified models, pressure-flow equations, and piston rod displacement equation, a twin-tube shock absorber model is established. The method reduces computational complexity and modeling cost by rationally simplifying the damping valve, one-way valve, oil compression process, and oil leakage process, which are complex to model and computationally time-consuming. Furthermore, pressure-flow equations for the compression chamber, extension chamber, and oil storage chamber, as well as a displacement equation for the piston rod, are constructed to compensate for the modeling accuracy lost when constructing models of the damping valve and one-way valve, thereby enabling rapid and accurate overall modeling of the twin-tube shock absorber.

Description

Technical Field

[0001] The present application relates to the technical field of shock absorbers, and in particular to a modeling method and device for a double-tube shock absorber. Background Art

[0002] As a key component of a vehicle's chassis suspension system, twin-tube shock absorbers effectively mitigate road impacts on the vehicle body. During dynamics simulations, they require modeling to accurately simulate their mechanical properties and response behavior.

[0003] Based on different modeling principles, twin-tube shock absorber models are divided into three categories: physical parametric models, equivalent parametric models, and non-parametric models. Physical parametric models mathematically describe all aspects of the modeling process and rely on a large number of model parameter inputs. The modeling method is complex and the computational efficiency is extremely low. The equivalent parametric model abstracts the twin-tube shock absorber as a mechanical element, requiring fewer parameters and fast calculation speed. However, due to a large number of simplifications and equivalences, it cannot accurately describe the amplitude-frequency characteristics of the twin-tube shock absorber, and the performance is significantly different from that of the physical sample. The non-parametric model is a black box model based on experimental data analysis. It relies on physical prototypes and a large amount of experimental data, and the required experimental costs are relatively high.

[0004] In summary, physical parametric models are not suitable for vehicle dynamics simulation due to their extremely low computational efficiency. Equivalent parametric and non-parametric models also fail to adequately reflect the full frequency- and amplitude-dependent characteristics of twin-tube shock absorbers, resulting in low computational accuracy. Therefore, how to quickly and cost-effectively model twin-tube shock absorbers while ensuring modeling accuracy has become a pressing challenge. Summary of the Invention

[0005] The present application provides a modeling method and device for a double-tube shock absorber, which can quickly model the double-tube shock absorber while ensuring modeling accuracy.

[0006] In a first aspect, an embodiment of the present application provides a modeling method for a twin-tube shock absorber, the method comprising:

[0007] Establish simplified models of the twin-tube shock absorber's damping valve, one-way valve, oil compression process, and oil leakage process;

[0008] Establish the pressure and flow equations for the compression chamber, extension chamber and oil storage chamber of the twin-tube shock absorber;

[0009] Establish the displacement equation of the piston rod of the twin-tube shock absorber;

[0010] Based on the simplified models, the pressure-flow equations, and the displacement equation of the piston rod, a model of a twin-tube shock absorber is established.

[0011] In conjunction with the first aspect, in one embodiment, establishing a simplified model of the damping valve includes:

[0012] Converting the macroscopic static damping characteristic curve of the twin-tube shock absorber into the pressure-flow relationship curve of the damping valve;

[0013] Based on the pressure-flow relationship curve and preset modeling software, a simplified model of the damping valve is established.

[0014] In conjunction with the first aspect, in one embodiment, establishing a simplified model of the one-way valve includes:

[0015] The one-way valve is considered as a normally open hole, which only allows oil flow in one direction;

[0016] A flow formula of the one-way valve is obtained based on the oil density of the one-way valve, the oil pressure difference of the one-way valve, the area of ​​the one-way valve hole, and the flow coefficient of the one-way valve hole;

[0017] Based on the flow formula of the one-way valve and preset modeling software, a simplified model of the one-way valve is established.

[0018] In conjunction with the first aspect, in one embodiment, establishing a simplified model of the oil compression process includes:

[0019] Obtaining an effective bulk modulus of the oil based on the bulk modulus of the oil, the solubility of air in the oil, and the operating pressure of the twin-tube shock absorber;

[0020] Based on the time derivative of the pressure in each chamber of the twin-tube shock absorber, the instantaneous volume in each chamber, and the effective bulk elastic modulus of the oil, the volume change in each chamber due to oil compression is obtained;

[0021] Based on the volume change and preset modeling software, a simplified model of the oil compression process is established.

[0022] In conjunction with the first aspect, in one embodiment, establishing a simplified model of the oil leakage process includes:

[0023] Based on the leakage flow rate, piston radius, flow channel length, single-side clearance, eccentricity, oil dynamic viscosity, and pressure difference across the gap of the double-tube shock absorber, the flow rate formula of the cylindrical annular gap is obtained;

[0024] Based on the cylindrical annular gap flow rate formula and preset modeling software, a simplified model of the oil leakage process is established.

[0025] In conjunction with the first aspect, in one embodiment, establishing a pressure-flow equation for the compression chamber of the twin-tube shock absorber includes:

[0026] Based on the cross-sectional area of ​​the piston of the twin-tube shock absorber, the piston speed, the instantaneous displacement of the piston in the compression stroke direction, the length of the inner sleeve, the instantaneous pressure of the compression chamber, and the effective bulk elastic modulus of the oil in the compression chamber, a pressure-flow equation for the compression chamber of the twin-tube shock absorber is established.

[0027] In conjunction with the first aspect, in one embodiment, establishing a pressure-flow equation for the stretching chamber of the twin-tube shock absorber includes:

[0028] Based on the cross-sectional area of ​​the piston of the twin-tube shock absorber, the piston speed, the cross-sectional area of ​​the piston rod, the length of the inner sleeve, the instantaneous displacement of the piston in the compression stroke direction, the instantaneous pressure of the stretching chamber, and the effective bulk elastic modulus of the oil in the stretching chamber, a pressure-flow equation for the stretching chamber of the twin-tube shock absorber is established.

[0029] In combination with the first aspect, in one embodiment, establishing a pressure-flow equation for the oil storage chamber of the twin-tube shock absorber includes:

[0030] Based on the total volume of the oil storage chamber, the instantaneous pressure of the air portion in the oil storage chamber, the bulk elastic modulus of the oil, the adiabatic constant, the instantaneous pressure of the oil storage chamber, the air volume in the oil storage chamber when the twin-tube shock absorber is fully extended, and the air pressure in the oil storage chamber when the twin-tube shock absorber is fully extended, a pressure-flow equation for the oil storage chamber of the twin-tube shock absorber is established.

[0031] In combination with the first aspect, in one embodiment, establishing the displacement equation of the piston rod of the twin-tube shock absorber includes:

[0032] The displacement equation of the piston rod of the twin-tube shock absorber is established based on the series stiffness of the rubber joint of the twin-tube shock absorber, the piston diameter of the twin-tube shock absorber, the diameter of the piston guide rod of the twin-tube shock absorber, the instantaneous pressure of the compression chamber and the instantaneous pressure of the tension chamber.

[0033] In a second aspect, an embodiment of the present application provides a modeling device for a double-tube shock absorber based on the above method, characterized in that the device comprises:

[0034] Component modeling module, used to build simplified models of the twin-tube shock absorber's damping valve, one-way valve, oil compression process, and oil leakage process;

[0035] A calculation module is used to establish the pressure and flow equations of the compression chamber, tension chamber, and oil storage chamber of the twin-tube shock absorber; and to establish the displacement equation of the piston rod of the twin-tube shock absorber;

[0036] The overall modeling module is used to establish a model of the double-tube shock absorber based on the simplified models, the pressure-flow equations, and the displacement equation of the piston rod.

[0037] The beneficial effects of the technical solutions provided in the embodiments of the present application include:

[0038] This application reduces the computational complexity and modeling cost by reasonably simplifying the damping valve, one-way valve, oil compression process and oil leakage process, which are complex to model and time-consuming to calculate, and constructs the pressure flow equations of the compression chamber, stretching chamber and oil storage chamber and the displacement equation of the piston rod to compensate for the loss of modeling accuracy when constructing models such as the damping valve and one-way valve, thereby enabling the double-tube shock absorber to be quickly and accurately modeled as a whole based on the simplified models and equations. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the flow of the modeling method of the double-tube shock absorber according to the embodiment of the present application;

[0040] Figure 2 A schematic diagram of the flow in the cylindrical annular gap of the modeling method of the double-tube shock absorber according to an embodiment of the present application;

[0041] Figure 3 Schematic diagram of piston rod displacement for a modeling method of a twin-tube shock absorber according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] First, some technical terms in this application are explained to facilitate those skilled in the art to understand this application.

[0044] Twin Tube Damper: A twin-tube damper has two cylinders (a working cylinder and a reservoir). As the piston moves in the working cylinder, the oil volume in the inner cylinder contracts and expands as the piston rod moves in and out. Therefore, oil balance is maintained by exchanging oil with the outer cylinder. During the compression stroke (when the axle and frame move closer together), the twin-tube damper's damping force is high, fully utilizing the elasticity of the elastic element to mitigate impact. During the extension stroke (when the axle and frame move away from each other), the twin-tube damper's damping force is low, resulting in rapid shock absorption.

[0045] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0046] First, please refer to Figure 1 , Figure 1 The figure is a flow chart of the modeling method of the double-tube shock absorber according to the embodiment of the present application. The modeling method of the double-tube shock absorber provided in the embodiment of the present application includes the following steps:

[0047] Step S1: Establish a simplified model of the damping valve, the one-way valve, the oil compression process, and the oil leakage process of the twin-tube shock absorber.

[0048] Step S2: Establishing the pressure-flow equations of the compression chamber, the tension chamber, and the oil storage chamber of the twin-tube shock absorber.

[0049] Step S3: Establish a displacement equation of the piston rod of the twin-tube shock absorber.

[0050] Step S4: Building a twin-tube shock absorber model based on the simplified models, the pressure-flow equations, and the piston rod displacement equation.

[0051] This application reduces the computational complexity and modeling cost by reasonably simplifying the damping valve, one-way valve, oil compression process and oil leakage process, which are complex to model and time-consuming to calculate, and constructs the pressure flow equations of the compression chamber, stretching chamber and oil storage chamber and the displacement equation of the piston rod to compensate for the loss of modeling accuracy when constructing models such as the damping valve and one-way valve, thereby enabling the double-tube shock absorber to be quickly and accurately modeled as a whole based on the simplified models and equations.

[0052] In some embodiments, in the above step S1, establishing a simplified model of the damping valve includes the following steps:

[0053] Firstly, the macro-static damping characteristic curve of the twin-tube shock absorber is converted into the pressure-flow relationship curve of the damping valve.

[0054] Afterwards, a simplified model of the damping valve was established based on the pressure-flow relationship curve and the preset modeling software.

[0055] In this embodiment, the preset modeling software is MATLAB, the macro-static damping characteristic curve is FV, ​​F is the damping force, V is the speed of the piston of the double-tube shock absorber, and the pressure-flow relationship curve is ΔP-Q, ΔP is the pressure difference acting on the damping valve, and Q is the flow rate through the damping valve.

[0056] When the twin-tube shock absorber is in the compression stroke, the calculation formulas for ΔP and Q are:

[0057]

[0058] Q=VA rod (2)

[0059] In formula (1), F is the damping force, ΔP is the pressure difference acting on the damping valve, and A is rod is the cross-sectional area of ​​the piston rod of the twin-tube shock absorber.

[0060] In formula (2), Q is the flow rate through the damping valve, V is the speed of the piston of the twin-tube shock absorber, and A is rod is the cross-sectional area of ​​the piston rod of the twin-tube shock absorber.

[0061] When the twin-tube shock absorber is in the extension stroke, the calculation formulas for ΔP and Q are:

[0062]

[0063] Q=V(A psi -A rod )(4)

[0064] In formula (3), ΔP is the pressure difference acting on the damping valve, F is the damping force, and A is rod is the cross-sectional area of ​​the piston rod of the twin-tube shock absorber, A psi is the cross-sectional area of ​​the piston of the twin-tube shock absorber.

[0065] In formula (4), Q is the flow rate through the damping valve, V is the speed of the piston of the twin-tube shock absorber, and A is rod is the cross-sectional area of ​​the piston rod of the twin-tube shock absorber, A psi is the cross-sectional area of ​​the piston of the twin-tube shock absorber.

[0066] It should be noted that describing the dynamic behavior of the damping valve by using the above pressure-flow relationship curve greatly improves the modeling speed of the damping valve.

[0067] In some embodiments, in the above step S1, establishing a simplified model of a one-way valve includes the following steps:

[0068] First, think of a check valve as a normally open orifice that only allows oil flow in one direction.

[0069] Then, the flow formula of the check valve is obtained based on the oil density of the check valve, the oil pressure difference of the check valve, the area of ​​the check valve hole, and the flow coefficient of the check valve hole.

[0070] Finally, based on the flow formula of the one-way valve and the preset modeling software, a simplified model of the one-way valve is established.

[0071] In this embodiment, the preset modeling software is MATLAB, and the flow formula of the one-way valve is as follows:

[0072]

[0073] In formula (5), Q is the flow rate of the one-way valve, C d is the flow coefficient of the one-way valve hole, A c is the area of ​​the one-way valve hole, ΔP is the oil pressure difference of the one-way valve, and ρ is the oil density of the one-way valve.

[0074] It should be noted that solving the pressure-flow equation for a check valve requires executing numerous judgment statements, which is time-consuming. Furthermore, a check valve can open with very small oil pressure differentials. Therefore, to simplify modeling, the check valve can be treated as a normally open orifice, allowing oil flow in only one direction.

[0075] In some embodiments, in the above step S1, a simplified model of the oil compression process is established, including the following steps:

[0076] First, the effective bulk modulus of the oil is obtained based on the bulk modulus of the oil, the solubility of air in the oil, and the working pressure of the twin-tube shock absorber.

[0077] Then, based on the time derivative of the pressure in each chamber of the twin-tube shock absorber, the instantaneous volume in each chamber, and the effective bulk elastic modulus of the oil, the volume change in each chamber due to oil compression is calculated.

[0078] Finally, based on the above volume changes and the preset modeling software, a simplified model of the oil compression process was established.

[0079] In this embodiment, the preset modeling software is MATLAB, and the calculation formula of the effective bulk elastic modulus of the oil is as follows:

[0080]

[0081] In formula (6), E oileff is the effective bulk elastic modulus of the oil, E oil is the bulk elastic modulus of the oil, P is the working pressure of the twin-tube shock absorber, ε is the nominal value of the solubility rate of air in the oil, and t is the oil temperature of the shock absorber. The oil temperature of the shock absorber during operation shows slight differences as the service conditions change.

[0082] It should be noted that, generally speaking, oil contains a few thousandths of dissolved air, so what is calculated here is the effective bulk elastic modulus of the oil containing a certain amount of dissolved air.

[0083] In this embodiment, the volume change in each chamber due to oil compression is calculated as follows:

[0084]

[0085] In formula (7), Q volumis the volume change in each chamber due to oil compression, V is the instantaneous volume in each chamber, is the time derivative of the pressure in each chamber, E oileff is the effective bulk elastic modulus of the oil.

[0086] In some embodiments, in the above step S1, a simplified model of the oil leakage process is established, including the following steps:

[0087] Based on the leakage flow rate, piston radius, flow channel length, single-side clearance, eccentricity, oil dynamic viscosity, and pressure difference across the gap of the double-tube shock absorber, the flow rate formula of the cylindrical annular gap is obtained;

[0088] Based on the cylindrical annular gap flow rate formula and preset modeling software, a simplified model of the oil leakage process is established.

[0089] In this embodiment, please refer to Figure 2 , Figure 2 This is a schematic diagram of the flow in the cylindrical annular gap of the modeling method of the double-tube shock absorber according to the embodiment of the present application. l is the piston radius of the twin-tube shock absorber, e l is the eccentricity of the twin-tube shock absorber, c l It is the single-side clearance of the twin-tube shock absorber.

[0090] according to Figure 2 The established flow formula for cylindrical annular gap flow is as follows:

[0091]

[0092] In formula (8), Q leak is the leakage flow of the twin-tube shock absorber, r l is the piston radius of the twin-tube shock absorber, L l is the flow channel length of the twin-tube shock absorber, c l is the unilateral clearance of the twin-tube shock absorber, e l is the eccentricity of the twin-tube shock absorber, μ is the dynamic viscosity of the oil in the unilateral gap of the twin-tube shock absorber, and ΔP is the pressure difference at both ends of the gap of the twin-tube shock absorber.

[0093] It should be noted that since the oil leakage flow of the twin-tube shock absorber is usually very small and can be regarded as laminar flow, a simplified model of the oil leakage process can be established according to the flow formula of the cylindrical annular gap.

[0094] In some embodiments, in the above step S2, establishing the pressure-flow equation of the compression chamber of the twin-tube shock absorber includes the following steps:

[0095] The pressure-flow equation of the compression chamber of the twin-tube shock absorber is established based on the cross-sectional area of ​​the piston, piston velocity, inner sleeve length, instantaneous pressure of the compression chamber, and effective bulk elastic modulus of the oil in the compression chamber.

[0096] In this embodiment, the pressure-flow equation of the compression chamber of the twin-tube shock absorber is as follows:

[0097]

[0098] In formula (9), Q com is the oil flow rate in the compression chamber, A psi is the cross-sectional area of ​​the twin-tube shock absorber's piston, L is the length of the inner sleeve of the twin-tube shock absorber, x is the instantaneous displacement of the twin-tube shock absorber's piston in the compression stroke direction, is the effective bulk elastic modulus of the oil in the compression chamber, is the instantaneous pressure of the compression chamber, is the speed of the piston of the twin-tube shock absorber, where x min 、x max are the upper and lower limits of the shock absorber stroke, which are determined by the geometric deformation limit of the rubber joint. When establishing this equation, it is assumed that the piston center position of the twin-tube shock absorber is zero.

[0099] It should be noted that in the compression chamber, the volume change of the piston movement is equal to the sum of the total flow rate of the chamber and the volume compression of the oil.

[0100] In some embodiments, in the above step S2, establishing the pressure-flow equation of the stretching chamber of the twin-tube shock absorber includes the following steps:

[0101] The pressure-flow equation of the stretching chamber of the twin-tube shock absorber is established based on the cross-sectional area of ​​the piston, piston velocity, cross-sectional area of ​​the piston rod, length of the inner sleeve, instantaneous pressure of the stretching chamber, and effective bulk elastic modulus of the oil in the stretching chamber.

[0102] In this embodiment, the pressure-flow equation of the stretching chamber of the twin-tube shock absorber is as follows:

[0103]

[0104] In formula (10), Q reb is the oil flow rate of the stretching chamber, A psi is the cross-sectional area of ​​the piston of the twin-tube shock absorber, A rod is the cross-sectional area of ​​the piston rod of the twin-tube shock absorber, L is the length of the inner sleeve of the twin-tube shock absorber, x is the instantaneous displacement of the piston of the twin-tube shock absorber in the direction of the compression stroke, is the effective bulk elastic modulus of the oil in the tensile cavity, is the instantaneous pressure of the stretching chamber, is the speed of the twin-tube shock absorber piston. When establishing this equation, it is assumed that the center position of the twin-tube shock absorber piston is zero.

[0105] In some embodiments, in the above step S2, establishing the pressure-flow equation of the oil storage chamber of the twin-tube shock absorber includes:

[0106] The pressure-flow equation of the oil reservoir of the twin-tube shock absorber is established based on the total volume of the oil reservoir, the instantaneous pressure of the air portion in the oil reservoir, the bulk elastic modulus of the oil, the adiabatic constant, the instantaneous pressure of the oil reservoir, the air volume in the oil reservoir when the twin-tube shock absorber is fully extended, and the air pressure in the oil reservoir when the twin-tube shock absorber is fully extended.

[0107] In this embodiment, the pressure-flow equation of the oil storage chamber of the twin-tube shock absorber is as follows:

[0108]

[0109] In formula (11), Q aux is the oil flow rate of the oil storage chamber, V aux is the total volume of the oil storage chamber, E oil is the bulk elastic modulus of the oil, P a is the instantaneous pressure of the air in the oil storage chamber, P a0 V is the air pressure in the oil storage chamber when the twin-tube shock absorber is fully extended. a0 is the air volume in the oil storage cavity when the twin-tube shock absorber is fully extended, γ is the adiabatic constant, is the instantaneous pressure of the oil storage chamber.

[0110] In some embodiments, when the twin-tube shock absorber is in the compression stroke, the total flow rate of oil passing through the compression chamber, the extension chamber, and the oil storage chamber can be expressed by the following formula:

[0111]

[0112] In formula (12), Q com is the oil flow rate in the compression chamber, Q com→reb It is the oil flow from the compression chamber to the stretching chamber through the one-way valve on the piston. Q is the oil flow rate leaking from the compression chamber to the stretching chamber between the piston and the inner sleeve, reb is the oil flow rate of the stretching chamber, Q reb→aux The oil flow from the stretching chamber to the oil storage chamber through the damping valve is Q is the oil flow rate leaking from the piston guide rod and guide seat to the oil storage chamber through the stretching chamber, aux is the oil flow rate in the oil storage chamber.

[0113] In some embodiments, when the twin-tube shock absorber is in the extension stroke, the total flow rate of oil passing through the compression chamber, the extension chamber, and the oil storage chamber can be expressed by the following formula:

[0114]

[0115] In formula (13), Q com is the oil flow rate in the compression chamber, Q aux→com It is the oil flow from the oil storage chamber to the compression chamber through the base one-way valve. Q is the oil flow rate between the piston and the inner sleeve that leaks from the stretching chamber to the compression chamber. reb is the oil flow rate of the stretching chamber, Q reb→aux The oil flow from the stretching chamber to the oil storage chamber through the damping valve is Q is the oil flow rate leaking from the piston guide rod and guide seat to the oil storage chamber through the stretching chamber, aux is the oil flow rate in the oil storage chamber.

[0116] In some embodiments, in the above step S3, establishing the displacement equation of the piston rod of the twin-tube shock absorber includes the following steps:

[0117] The displacement equation of the piston rod of the twin-tube shock absorber is established based on the series stiffness of the rubber joint of the twin-tube shock absorber, the piston diameter of the twin-tube shock absorber, the piston guide rod diameter of the twin-tube shock absorber, the instantaneous pressure of the compression chamber and the instantaneous pressure of the oil storage chamber.

[0118] It should be noted that twin-tube shock absorbers typically have rubber joints installed at both ends to prevent bending moments in the piston rod during movement and reduce the transmission of high-frequency vibrations. When developing the displacement equation for the piston rod of a twin-tube shock absorber, the stiffness of the rubber joints at both ends of the shock absorber must be considered. When rubber joints are installed at both ends of a twin-tube shock absorber, the following formula can be established:

[0119]

[0120] In formula (14), k att is the series stiffness of the rubber joints at both ends of the twin-tube shock absorber, u is the external displacement excitation of the twin-tube shock absorber, F psi is the force acting on the piston of the twin-tube shock absorber, and x is the displacement of the piston rod of the twin-tube shock absorber. When the shock absorber displacement reaches the limit value, the force on the piston is considered to be infinite.

[0121] In (x min <x<x max ) interval, F psi The specific calculation method can refer to the following formula:

[0122]

[0123] In formula (15), F psi is the force acting on the piston of the twin-tube shock absorber, A psi is the cross-sectional area of ​​the piston of the twin-tube shock absorber, P com is the instantaneous pressure of the compression chamber, A rod is the cross-sectional area of ​​the piston rod of the twin-tube shock absorber, P reb is the instantaneous pressure of the stretching chamber, d psi is the piston diameter of the twin-tube shock absorber, d rod is the piston guide rod diameter of the twin-tube shock absorber.

[0124] Combining formula (14) and formula (15), the displacement equation of the piston rod of the double-tube shock absorber can be derived:

[0125]

[0126] In formula (16), x is the displacement of the piston rod of the twin-tube shock absorber, u is the external displacement excitation of the twin-tube shock absorber, and k att is the series stiffness of the rubber joints at both ends of the twin-tube shock absorber, d psi is the piston diameter of the twin-tube shock absorber, d rod is the piston guide rod diameter of the twin-tube shock absorber, P com is the instantaneous pressure of the compression chamber, P reb is the instantaneous pressure of the stretching chamber.

[0127] For details, please refer to Figure 3 , Figure 3 This is a schematic diagram of the piston rod displacement of the modeling method of the double-tube shock absorber in the embodiment of the present application. Figure 3 Where u is the external displacement excitation of the twin-tube shock absorber, x is the displacement of the piston rod of the twin-tube shock absorber, and k is att is the series stiffness of the rubber joints at both ends of the twin-tube shock absorber, F psi is the force acting on the piston of the twin-tube shock absorber, P reb is the instantaneous pressure of the stretching chamber, P com is the instantaneous pressure of the compression chamber.

[0128] In a second aspect, an embodiment of the present application provides a modeling device for a double-tube shock absorber, the device comprising the following modules:

[0129] The component modeling module is used to establish simplified models of the damping valve, one-way valve, oil compression process, and oil leakage process of the twin-tube shock absorber.

[0130] The calculation module is used to establish the pressure flow equations of the compression chamber, the tension chamber and the oil storage chamber of the twin-tube shock absorber, and is also used to establish the displacement equation of the piston rod of the twin-tube shock absorber.

[0131] The overall modeling module is used to establish a model of a double-tube shock absorber based on various simplified models, various pressure-flow equations, and the displacement equation of the piston rod.

[0132] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0133] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0134] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0135] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0136] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0137] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of the present application.

[0138] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A modeling method for a double-tube shock absorber, characterized in that: The method comprises: Establish simplified models of the twin-tube shock absorber's damping valve, one-way valve, oil compression process, and oil leakage process; Establish the pressure and flow equations for the compression chamber, extension chamber and oil storage chamber of the twin-tube shock absorber; Establish the displacement equation of the piston rod of the twin-tube shock absorber; Based on the simplified models, the pressure-flow equations, and the displacement equation of the piston rod, a model of a twin-tube shock absorber is established; A simplified model of the damping valve is established, including: Converting the macroscopic static damping characteristic curve of the twin-tube shock absorber into the pressure-flow relationship curve of the damping valve; Based on the pressure-flow relationship curve and preset modeling software, a simplified model of the damping valve is established; A simplified model of the one-way valve is established, including: The one-way valve is considered as a normally open hole, which only allows oil flow in one direction; A flow formula of the one-way valve is obtained based on the oil density of the one-way valve, the oil pressure difference of the one-way valve, the area of ​​the one-way valve hole, and the flow coefficient of the one-way valve hole; Based on the flow formula of the one-way valve and the preset modeling software, a simplified model of the one-way valve is established; A simplified model of the oil compression process is established, including: Obtaining an effective bulk modulus of the oil based on the bulk modulus of the oil, the solubility of air in the oil, and the operating pressure of the twin-tube shock absorber; Based on the time derivative of the pressure in each chamber of the twin-tube shock absorber, the instantaneous volume in each chamber, and the effective bulk elastic modulus of the oil, the volume change in each chamber due to oil compression is obtained; Based on the volume change and preset modeling software, a simplified model of the oil compression process is established; A simplified model of the oil leakage process is established, including: Based on the leakage flow rate, piston radius, flow channel length, single-side clearance, eccentricity, oil dynamic viscosity, and pressure difference across the gap of the double-tube shock absorber, the flow rate formula of the cylindrical annular gap is obtained; Based on the cylindrical annular gap flow rate formula and preset modeling software, a simplified model of the oil leakage process is established.

2. The modeling method of a twin-tube shock absorber according to claim 1, wherein: The pressure-flow equation of the compression chamber of the twin-tube shock absorber is established, including: Based on the cross-sectional area of ​​the piston of the twin-tube shock absorber, the piston speed, the instantaneous displacement of the piston in the compression stroke direction, the length of the inner sleeve, the instantaneous pressure of the compression chamber, and the effective bulk elastic modulus of the oil in the compression chamber, a pressure-flow equation for the compression chamber of the twin-tube shock absorber is established.

3. The modeling method of a twin-tube shock absorber according to claim 1, wherein: The pressure-flow equation of the stretching chamber of the twin-tube shock absorber is established, including: Based on the cross-sectional area of ​​the piston of the twin-tube shock absorber, the piston speed, the cross-sectional area of ​​the piston rod, the length of the inner sleeve, the instantaneous displacement of the piston in the compression stroke direction, the instantaneous pressure of the stretching chamber, and the effective bulk elastic modulus of the oil in the stretching chamber, a pressure-flow equation for the stretching chamber of the twin-tube shock absorber is established.

4. The modeling method of a twin-tube shock absorber according to claim 1, wherein: The pressure-flow equation of the oil storage chamber of the twin-tube shock absorber is established, including: Based on the total volume of the oil storage chamber, the instantaneous pressure of the air portion in the oil storage chamber, the bulk elastic modulus of the oil, the adiabatic constant, the instantaneous pressure of the oil storage chamber, the air volume in the oil storage chamber when the twin-tube shock absorber is fully extended, and the air pressure in the oil storage chamber when the twin-tube shock absorber is fully extended, a pressure-flow equation for the oil storage chamber of the twin-tube shock absorber is established.

5. The modeling method of a twin-tube shock absorber according to claim 1, wherein: The displacement equation of the piston rod of the twin-tube shock absorber is established, including: The displacement equation of the piston rod of the twin-tube shock absorber is established based on the series stiffness of the rubber joint of the twin-tube shock absorber, the piston diameter of the twin-tube shock absorber, the diameter of the piston guide rod of the twin-tube shock absorber, the instantaneous pressure of the compression chamber and the instantaneous pressure of the tension chamber.

6. A modeling device for a double-tube shock absorber based on the method according to any one of claims 1 to 5, characterized in that: The device comprises: Component modeling module, used to build simplified models of the twin-tube shock absorber's damping valve, one-way valve, oil compression process, and oil leakage process; A calculation module is used to establish the pressure and flow equations of the compression chamber, tension chamber, and oil storage chamber of the twin-tube shock absorber; and to establish the displacement equation of the piston rod of the twin-tube shock absorber; The overall modeling module is used to establish a model of the double-tube shock absorber based on the simplified models, the pressure-flow equations, and the displacement equation of the piston rod.

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