阅读说明：本技术 一种确定后悬架的最优化导向性能的方法 (Method for determining optimal guiding performance of rear suspension ) 是由 熊新 郑竹安 石小龙 翟豪瑞 孙婷婷 于 2020-08-05 设计创作，主要内容包括：本发明公开了一种确定后悬架的最优化导向性能的方法,上摆臂和下摆臂的长度比确认,首先进行耐磨性试验,当上摆臂和下摆臂的长度比在0.6时,摩擦系数最低,随后进行操稳性试验,当上摆臂和下摆臂的长度比在1.0时,操稳性能达到最佳,随后对耐磨性和操稳性同时检测,当上摆臂和下摆臂的长度比在0.65时,耐磨性和操稳性的综合性能达到最佳,弹性元件刚度的确认,对减震器相对阻尼系数及阻尼系数进行确认,对横向稳定杆的刚度进行确认,本发明确认方法能保证汽车具有出色的竞争性和稳定性以及安全性,同时在转向时保证汽车具有不足转向特性。(The invention discloses a method for determining the optimal guiding performance of a rear suspension, which comprises the steps of confirming the length ratio of an upper swing arm and a lower swing arm, firstly carrying out an abrasion resistance test, when the length ratio of the upper swing arm to the lower swing arm is 0.6, the friction coefficient is lowest, then carrying out a stability test, when the length ratio of the upper swing arm to the lower swing arm is 1.0, the stability can reach the best, then simultaneously detecting the abrasion resistance and the stability, when the length ratio of the upper swing arm to the lower swing arm is 0.65, the comprehensive performance of the abrasion resistance and the stability can reach the best, confirming the rigidity of an elastic element, confirming the relative damping coefficient and the damping coefficient of a shock absorber, and confirming the rigidity of a transverse stabilizer bar.)

1. A method of determining optimal guidance performance for a rear suspension, comprising: the method comprises the following steps:

the method comprises the following steps: confirming the length ratio of the upper swing arm and the lower swing arm, firstly carrying out an abrasion resistance test, when the length ratio of the upper swing arm to the lower swing arm is 0.6, the friction coefficient is lowest, then carrying out a stability operation test, when the length ratio of the upper swing arm to the lower swing arm is 1.0, the stability operation can reach the best, then simultaneously detecting the abrasion resistance and the stability operation, and when the length ratio of the upper swing arm to the lower swing arm is 0.65, the comprehensive performance of the abrasion resistance and the stability operation can reach the best;

step two: confirming the rigidity of the elastic element, acquiring the rigidity of a suspension system according to the load of a front axle and the determined offset frequency value in a full-load state, and calculating the rigidity of a spiral spring through a lever ratio;

step three: confirming the relative damping coefficient and damping coefficient of the shock absorber;

step four: the rigidity of the stabilizer bar was confirmed.

2. A method of determining optimal guidance performance for a rear suspension according to claim 1, wherein: and in the first step, the upper swing arm and the lower swing arm are arranged in parallel, and the upper swing arm and the lower swing arm are both connected with the rear suspension.

3. A method of determining optimal guidance performance for a rear suspension according to claim 1, wherein: in the first step, the length of the upper swing arm is 212mm, and the length of the lower swing arm is 326 mm.

4. A method of determining optimal guidance performance for a rear suspension according to claim 1, wherein: and in the second step, the elastic element adopts a spring.

5. A method of determining optimal guidance performance for a rear suspension according to claim 1, wherein: and the shock absorber in the third step is a cylinder type shock absorber.

6. A method of determining optimal guidance performance for a rear suspension according to claim 1, wherein: and in the fourth step, the transverse stabilizer bar is connected with the rear suspension.

Technical Field

The invention relates to the technical field of methods for determining the optimal guiding performance of a rear suspension, in particular to a method for determining the optimal guiding performance of the rear suspension.

Background

The suspension is a general term for all force-transmitting connecting devices between the frame of an automobile and the axle or wheel, and is used for transmitting force and moment acting between the wheel and the frame. An automobile has front and rear suspensions. The guiding function is used for determining the motion relation of the wheel relative to the frame (or the vehicle body) and transmitting longitudinal force, lateral force and moment caused by the longitudinal force and the lateral force.

The optimal guiding performance of the rear suspension is well determined, so that a transmission system of the automobile is better optimized, the automobile can be guaranteed to have excellent competitiveness, stability and safety, and meanwhile the automobile is guaranteed to have understeer characteristic when turning.

Disclosure of Invention

The present invention is directed to a method for determining optimal guiding performance of a rear suspension to solve the above-mentioned problems of the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a method of determining optimal guidance performance for a rear suspension, comprising the steps of:

the method comprises the following steps: confirming the length ratio of the upper swing arm and the lower swing arm, firstly carrying out an abrasion resistance test, when the length ratio of the upper swing arm to the lower swing arm is 0.6, the friction coefficient is lowest, then carrying out a stability operation test, when the length ratio of the upper swing arm to the lower swing arm is 1.0, the stability operation can reach the best, then simultaneously detecting the abrasion resistance and the stability operation, and when the length ratio of the upper swing arm to the lower swing arm is 0.65, the comprehensive performance of the abrasion resistance and the stability operation can reach the best;

step two: confirming the rigidity of the elastic element, acquiring the rigidity of a suspension system according to the load of a front axle and the determined offset frequency value in a full-load state, and calculating the rigidity of a spiral spring through a lever ratio;

step three: confirming the relative damping coefficient and damping coefficient of the shock absorber;

step four: the rigidity of the stabilizer bar was confirmed.

Preferably, in the first step, the upper swing arm and the lower swing arm are arranged in parallel, and the upper swing arm and the lower swing arm are both connected with the rear suspension.

Preferably, in the first step, the length of the upper swing arm is 212mm, and the length of the lower swing arm is 326 mm.

Preferably, the elastic element in the second step is a spring.

Preferably, the shock absorber in the third step is a cylinder type shock absorber.

Preferably, the stabilizer bar of the fourth step is connected to the rear suspension.

Compared with the prior art, the invention has the beneficial effects that:

the method is simple and reasonable, and can ensure excellent competitiveness, stability and safety of the automobile and ensure that the automobile has understeer characteristics during steering.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: a method of determining optimal guidance performance for a rear suspension, comprising the steps of:

the method comprises the following steps: the length ratio of the upper swing arm and the lower swing arm is confirmed, firstly, an abrasion resistance test is carried out, when the length ratio of the upper swing arm to the lower swing arm is 0.6, the friction coefficient is lowest, then, an operation stability test is carried out, when the length ratio of the upper swing arm to the lower swing arm is 1.0, the operation stability can reach the best, then, the abrasion resistance and the operation stability are simultaneously detected, when the length ratio of the upper swing arm to the lower swing arm is 0.65, the comprehensive performance of the abrasion resistance and the operation stability reaches the best, the length of the upper swing arm is 212mm, and the length of the lower swing arm is 326 mm.

Step two: and (3) confirming the rigidity of the elastic element, acquiring the rigidity of a suspension system according to the load of a front axle and the determined offset frequency value in a full-load state, and calculating the rigidity of the spiral spring through a lever ratio.

Because of the relationship of the suspension guide mechanism, the suspension stiffness C is not equal to the spring stiffness C, and the difference is that the suspension stiffness C refers to the force required by unit deflection at the wheel; whereas the spring rate C refers only to the force required per unit deflection of the spring itself. And in a full-load state, the rigidity of a suspension system is obtained according to the load of a front axle and the determined offset frequency value, and the rigidity of the spiral spring is calculated through the lever ratio.

Suspension stiffness C and spring stiffness C_sThe relationship is as follows:

in the formulaThe installation angle of the damper cylinder is 10 °, and α is 10 °. The following are obtained by the guide mechanism and the installation requirements: l is_w＝2499.678mm；L_o’＝2417.616mm；L₁＝148.772mm；L＝208.772mm。

Substituting the formula to obtain:

the pitch diameter of the spring:

this can be calculated according to the following formula:

in the formula, i is the effective working turns of the spring, and 8 is taken firstly;

g-modulus of elasticity in shear of spring material, taken as 8.3X 10⁴Mpa；

d is the diameter of the spring steel wire, and 12 is taken.

Dm＝89.644mm

So that the determined diameter D is 12mm and the spring intermediate diameter D_m90mm, and 102m outside diameter D of the springThe effective working circle number i is 8, the support circle number of the spring is determined by the shape of the end part of the spring, and the support circle number n is taken₂＝2.0

The total number of turns: n ═ i ═ n₂＝8+2.0＝10

Spring pitch: t ═ 0.3-0.5) D_m

Take t 0.3D 0.3X 90 27mm

Spring spacing:

＝t-d

＝27-12＝15mm

the free height of the spring is as follows:

H₀＝i_t+d

H₀＝8×27+12＝228mm

checking a spring:

the calculation formula of the spring stiffness is as follows:

substituting data to calculate the spring rate C_SComprises the following steps:

the spring selection meets the stiffness requirements.

Torsional stress formula:

and K' is a curvature coefficient, and is a coefficient considering the influence of the curvature of the spring coil on the strength.

Known as D_mThe spring index C and the camber coefficient K' can be calculated at 90mm and d at 12 mm:

C＝D_m/d＝90/12＝7.5

F_w＝438.75×9.8÷cos10°＝4366N

when fully loaded:

spring dynamic deflection:

and the data is brought in:

the maximum torsion of the spring is as follows:

take in data to get tau_d＝693.5N/mm²<[τ_c]＝800～1000N/mm²Meets the requirements. The spring selection meets the stiffness requirements.

Step three: confirming the relative damping coefficient and damping coefficient of the shock absorber;

(1) determination of the relative damping coefficient ψ:

the physical significance of the relative damping coefficient psi is: the damping action of the shock absorber being associated with different stiffness C and different sprung mass m_sThe suspension system of (a) can produce different damping effects when matched. The psi value is large, so that vibration can be quickly attenuated, and meanwhile, large road impact force can be transmitted to a vehicle body; if the value of psi is small, the relative damping coefficient psi in the compression stroke is normally set_YTaking the relative damping coefficient psi during the stretching stroke_SGet a larger value, keep psi between them_Y＝(0.25-0.50)ψ_SThe relationship (2) of (c).

When designing, firstly selecting psi_YAnd psi_SAverage value ψ of. Taking psi as 0.25-0.35 for elastic element suspension without friction; for bullets with internal frictionThe value psi is taken to be small, and psi is taken to avoid the suspension colliding with the vehicle frame_Y＝0.5ψ_SWhen ψ is 0.3, there are:calculating to obtain:

ψ_S＝0.4，ψ_Y＝0.2

(2) determination of damping coefficient of shock absorber:

to damp the coefficient, ω is the natural frequency of the suspension.

Of shock absorbers

Of suspension systems

Theoretically 2 psi m_sω. In fact, when the axis of the damper is at the same included angle with the vertical line,

because of this, it is possible to reduce the number of the,

therefore, the first and second electrodes are formed on the substrate,

n is 1.0, so:

ω＝2×3.14×1.0＝6.28rad

at this time, the maximum mass borne by the automobile is calculated as follows: m is 438.75kg, α is 10 ° into the data:

＝(2×0.3×438.75×6.28×0.208772²)/(0.148772²×0.96)＝3356.8N·s/m

substituting numerical formula to obtain_s＝4475.6，F₀＝_sV_xAnd carrying in data to obtain:

F₀＝_sV_x＝4475.6×0.176＝789N

determination of the diameter D of the shock absorber cylinder:

maximum unloading force F according to extension stroke₀Calculating the diameter D of the working cylinder as follows:

in the formula, the [ p ] is the maximum allowable pressure and is 3-4 MPa; λ is the ratio of the diameter of the connecting rod to the diameter of the cylinder, and λ is generally 0.40 to 0.50 for the dual-cylinder shock absorber.

Calculating by substituting:

selecting according to the standard.

The working cylinder diameter of the suspension damper is chosen to be of many sizes, here 30 mm.

Diameter D of oil storage cylinder_cThe thickness of the steel is 2mm (1.35-1.50) D, and the material is 20 steel. Here, the canister diameter is taken as:

D_c＝1.4D＝1.5×20＝42mm

the selectable piston rod diameters are: d is 13mm

The shock absorber of the selected suspension is of an HH type, and the base length is 120mm

Because of the lever ratio relationship, the stroke can be smaller than a specified range, so the piston stroke is selected as follows: 180mm for S

The shock absorber compresses to a length given by:

L_min＝L₂+s

L_max＝L₂+2s

therefore:

L_min＝L₂+s＝120+180＝300mm,L_max＝L₂+2s＝120+2×180＝480mm。

step four: the rigidity of the stabilizer bar was confirmed.

1) Angular stiffness C of front stabilizer bar₁

Known, effective working length 795mm, m₁250mm and 20mm stabilizer bar diameter.

The maximum working torsion angle of the stabilizer bar is as follows: b 22 ° -0.384 rad

Angular stiffness of a fore stabilizing bar

C₁＝πd⁴G/32B(N·mm/rad)

(3-22)

Front stabilizer bar torsional stress

τ＝16M_c/πd³(N/mm²)

In the formula, G_1----A shear elastic modulus; g₁＝75460(N/mm²)；

M_c-Torque (N.mm) M acting on the stabilizer bar_c＝C₁b；

Substituting the known data into the formula:

C₁＝πd₁ ⁴G/32B＝π×20⁴×75460/32×795

＝1490.97

torque acting on stabilizer bar

M_c＝C₁×b＝1490972.2×0.384＝572533.3N·m

M_c＝572.5N·m

Torsional stress

τ₁＝16M_c/πd₁ ³＝16×572533.3/π20³

τ₁＝364.49N/mm²。

The method is simple and reasonable, and can ensure excellent competitiveness, stability and safety of the automobile and ensure that the automobile has understeer characteristics during steering.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.