Modeling method and device for double-cylinder shock absorber

Abstract

The invention discloses a modeling method and device for a double-cylinder shock absorber, and relates to the technical field of shock absorbers, and the method comprises the steps: building simplified models of a damping valve, a one-way valve, an oil compression process and an oil leakage process of the double-cylinder shock absorber; establishing pressure flow equations of a compression cavity, a stretching cavity and an oil storage cavity of the double-cylinder shock absorber; establishing a displacement equation of a piston rod of the double-cylinder shock absorber; and based on each simplified model, each pressure flow equation and the displacement equation of the piston rod, establishing a model of the double-cylinder shock absorber. According to the method, a damping valve, a one-way valve, an oil compression process and an oil leakage process which are complex in modeling and time-consuming in calculation are reasonably simplified, so that the calculation complexity and the modeling cost are reduced, and pressure flow equations of a compression cavity, a stretching cavity and an oil storage cavity and a displacement equation of a piston rod are constructed; the modeling precision lost when models of a damping valve, a one-way valve and the like are constructed is made up, and therefore overall modeling can be rapidly and accurately conducted on the double-cylinder 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 the automobile chassis suspension system, the twin-tube shock absorber can effectively reduce the impact of the road on the vehicle body. In the dynamic simulation process, in order to accurately simulate the mechanical characteristics and response behavior of the twin-tube shock absorber, it is necessary to model it.

[0003] According to different modeling principles, the twin-tube shock absorber model is divided into three categories: physical parametric model, equivalent parametric model and non-parametric model. The physical parametric model mathematically describes all aspects of the modeling, relies on a large number of model parameter inputs, has a complex modeling method and extremely low calculation efficiency. The equivalent parametric model abstracts the twin-tube shock absorber as a mechanical element, requires fewer parameters and has a fast calculation speed. However, due to a large number of simplified equivalences, it is impossible to accurately describe the amplitude-frequency characteristics of the twin-tube shock absorber, and there is a large difference in performance from the physical sample. The non-parametric model is a black box model based on experimental data analysis, which relies on physical prototypes and a large amount of experimental data, and the required test cost is high.

[0004] In summary, the physical parametric model is not suitable for vehicle dynamics simulation due to its extremely low computational efficiency, while the equivalent parametric model and non-parametric model cannot well reflect the full frequency-variable and amplitude-variable characteristics of the twin-tube shock absorber, and the computational accuracy is low. Therefore, how to model the twin-tube shock absorber quickly and at low cost while ensuring modeling accuracy has become an urgent problem to be solved. 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 the modeling accuracy.

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

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

[0008] Establish the pressure-flow equations for the compression chamber, extension chamber and oil storage chamber of the double-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 combination with the first aspect, in one implementation, a simplified model of the damping valve is established, including:

[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 combination with the first aspect, in one implementation, a simplified model of the one-way valve is established, including:

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

[0016] 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, a flow formula of the one-way valve is obtained;

[0017] 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.

[0018] In combination with the first aspect, in one implementation, a simplified model of the oil compression process is established, including:

[0019] Based on the bulk elastic modulus of the oil, the solubility rate of air in the oil, and the working pressure of the twin-tube shock absorber, an effective bulk elastic modulus of the oil is obtained;

[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 caused by the 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 combination with the first aspect, in one implementation, a simplified model of the oil leakage process is established, including:

[0023] Based on the leakage flow rate, piston radius, flow channel length, single-side clearance, eccentricity, oil dynamic viscosity, and pressure difference at both ends of 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 combination with the first aspect, in one implementation, establishing a pressure flow equation of 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 volume 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 combination with the first aspect, in one implementation, establishing a pressure flow equation of the stretching chamber of the double-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 volume elastic modulus of the oil in the stretching chamber, the pressure-flow equation of the stretching chamber of the twin-tube shock absorber is established.

[0029] In combination with the first aspect, in one implementation, establishing a pressure flow equation of 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 part 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 implementation, establishing the displacement equation of the piston rod of the twin-tube shock absorber includes:

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

[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 establish simplified models of the damping valve, check valve, oil compression process and oil leakage process of the double-tube shock absorber;

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

[0036] The overall modeling module is used to establish a model of a 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 brought by the technical solution provided in the embodiments of the present application include:

[0038] The present 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, the stretching chamber and the 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 the 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 It is a flow chart of a modeling method of a double-tube shock absorber according to an 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 the embodiment of the present application;

[0041] Figure 3 Schematic diagram of piston rod displacement of a modeling method for a double-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 solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, 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 the present application are explained to facilitate those skilled in the art to understand the present application.

[0044] Twin Tube Damper: Twin Tube Damper has two inner and outer tubes (working cylinder and reservoir), the piston moves in the working cylinder, the volume of oil in the inner tube shrinks and increases as the piston rod enters and withdraws, so the oil balance in the inner tube must be maintained by exchanging with the outer tube. In the compression stroke (the axle and the frame are close to each other), the damping force of the twin tube shock absorber is large, which can give full play to the elastic effect of the elastic element and mitigate the impact; in the extension stroke (the axle and the frame are far away from each other), the damping force of the twin tube shock absorber is small, so that the shock can be quickly reduced.

[0045] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present 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 comprises 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: Establish 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 the 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 displacement equation of the piston rod.

[0051] The present 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, the stretching chamber and the 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 the 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 macroscopic 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 formula of ΔP and Q is:

[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 of 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 the dynamic behavior of the damping valve is described by the above pressure-flow relationship curve, which greatly improves the modeling speed of the damping valve.

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

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

[0069] Afterwards, 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, a simplified model of the one-way valve is established based on the flow formula of the one-way valve and the preset modeling software.

[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 of the one-way valve requires executing a large number of judgment statements, which takes a lot of time, and the one-way valve can be opened under a very small oil pressure difference. Therefore, in order to simplify the modeling, the one-way valve can be regarded as a normally open hole during modeling, 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] Firstly, the effective bulk elastic modulus of the oil is obtained based on the bulk elastic modulus of the oil, the solubility rate of air in the oil, and the working pressure of the twin-tube shock absorber.

[0077] Afterwards, 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 caused by the oil compression is obtained.

[0078] Finally, based on the above volume changes and the preset modeling software, a simplified model of the oil compression process is 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 at both ends of 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 formula and the preset modeling software, a simplified model of the oil leakage process is established.

[0089] In this embodiment, please refer to Figure 2 , Figure 2 Schematic diagram of the cylindrical annular gap flow of the modeling method of the double-tube shock absorber of the embodiment of the present application, in which r 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 cylindrical annular gap flow rate formula 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 single-side 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 single-side 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 cylindrical annular gap flow formula.

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

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

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

[0097]

[0098] In formula (9), Q com is the oil flow rate of the compression chamber, A psi is the cross-sectional area of ​​the piston 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 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 double-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 compression of the oil volume.

[0100] In some embodiments, in the above step S2, establishing the pressure flow equation of the stretching chamber of the double-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 speed, cross-sectional area of ​​the piston rod, length of the inner sleeve, instantaneous pressure of the stretching chamber, and effective volume elastic modulus of the oil in the stretching chamber.

[0102] In this embodiment, the pressure flow equation of the stretching chamber of the double-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 compression stroke direction, is the effective bulk elastic modulus of the oil in the tensile chamber, 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 double-tube shock absorber includes:

[0106] Based on the total volume of the oil storage chamber, the instantaneous pressure of the air part 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, the pressure-flow equation of the oil storage chamber of the twin-tube shock absorber is established.

[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 part 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 chamber 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 in 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 between the piston and the inner sleeve that leaks from the compression chamber to the stretching 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. Q is the oil flow rate leaking from the piston guide rod and the 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 in 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. Q is the oil flow rate leaking from the piston guide rod and the 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] 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, the displacement equation of the piston rod of the twin-tube shock absorber is established.

[0118] It should be noted that in order to prevent the piston rod from bearing bending moment during movement and reduce the transmission of high-frequency vibration, double-tube shock absorbers usually have rubber joints installed at both ends. When establishing the displacement equation of the piston rod of a double-tube shock absorber, the stiffness of the rubber joints at both ends of the shock absorber must be taken into account. When there are rubber joints at both ends of a double-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 double-tube shock absorber, u is the external displacement excitation of the double-tube shock absorber, F psi is the force on the piston of the twin-tube shock absorber, x is the displacement of the piston rod of the twin-tube shock absorber. When the shock absorber displacement stroke 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 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 In the equation, 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 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 double-tube shock absorber.

[0130] The calculation module is used to establish the pressure flow equations of the compression chamber, the stretching chamber and the oil storage chamber of the double-tube shock absorber, and is also used to establish the displacement equation of the piston rod of the double-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 only for description 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 "first", "second" and "third" to different types.

[0134] In the description of the embodiments of the present application, "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 the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[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; the “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 that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed 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 a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially 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, disk, CD) as described above, and includes a number of instructions for 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 are not intended to 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 damping valve, one-way valve, oil compression process and oil leakage process of the twin-tube shock absorber; Establish the pressure-flow equations for the compression chamber, extension chamber and oil storage chamber of the double-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.

2. The modeling method of the twin-tube shock absorber according to claim 1, characterized in that: 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.

3. The modeling method of the twin-tube shock absorber according to claim 2, characterized in that: A simplified model of the one-way valve is established, including: The one-way valve is regarded as a normally open hole, which only allows oil flow in one direction; 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, a flow formula of the one-way valve is obtained; 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.

4. The modeling method of a twin-tube shock absorber according to claim 2, characterized in that: A simplified model of the oil compression process is established, including: Based on the bulk elastic modulus of the oil, the solubility rate of air in the oil, and the working pressure of the twin-tube shock absorber, an effective bulk elastic modulus of the oil is obtained; 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 caused by the oil compression is obtained; Based on the volume change and preset modeling software, a simplified model of the oil compression process is established.

5. The modeling method of a twin-tube shock absorber according to claim 2, characterized in that: 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 at both ends of 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.

6. The modeling method of a twin-tube shock absorber according to claim 1, characterized in that: The pressure flow equation of the compression chamber of the double-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 volume 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.

7. The modeling method of a twin-tube shock absorber according to claim 1, characterized in that: The pressure flow equation of the stretching chamber of the double-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 volume elastic modulus of the oil in the stretching chamber, the pressure-flow equation of the stretching chamber of the twin-tube shock absorber is established.

8. The modeling method of a twin-tube shock absorber according to claim 1, characterized in that: The pressure flow equation of the oil storage chamber of the double-tube shock absorber is established, including: Based on the total volume of the oil storage chamber, the instantaneous pressure of the air part 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.

9. The modeling method of a twin-tube shock absorber according to claim 1, characterized in that: The method of establishing the displacement equation of the piston rod of the twin-tube shock absorber includes: Based on the series stiffness of the rubber joint of the double-tube shock absorber, the piston diameter of the double-tube shock absorber, the piston guide rod diameter of the double-tube shock absorber, the instantaneous pressure of the compression chamber and the instantaneous pressure of the stretching chamber, the displacement equation of the piston rod of the double-tube shock absorber is established.

10. A modeling device for a double-tube shock absorber based on the method according to any one of claims 1 to 9, characterized in that: The device comprises: Component modeling module, used to establish simplified models of the damping valve, check valve, oil compression process and oil leakage process of the double-tube shock absorber; A calculation module is used to establish the pressure flow equations of the compression chamber, the stretching chamber and the oil storage chamber of the double-tube shock absorber; and to establish the displacement equation of the piston rod of the double-tube shock absorber; The overall modeling module is used to establish a model of a 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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