CN115935554A - Design method and design terminal for multi-level-rigidity rear plate spring of light truck - Google Patents
Design method and design terminal for multi-level-rigidity rear plate spring of light truck Download PDFInfo
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Abstract
The invention provides a design method and a design terminal for a multi-stage rigidity rear plate spring of a light truck, and relates to the technical field of light truck spring suspensions. The invention provides a specific theoretical design method which ensures that the rigidity of each plate spring is in consideration of the comfort requirement of each bearing state; the service life of each plate spring is ensured to meet the requirement of fatigue times of the rack; the arc height of each plate spring is guaranteed to be set to meet the requirement that the full-load arc height of each plate spring is consistent in a full-load state, and the arrangement of the cushion blocks between the auxiliary spring cantilever support and the plate springs is guaranteed to avoid plate spring limit jumping without inter-plate contact. The smoothness and the reliability of the light truck are effectively guaranteed.
Description
Technical Field
The invention relates to the technical field of light truck spring suspensions, in particular to a design method and a design terminal of a rear plate spring with multi-level rigidity for a light truck.
Background
The light truck refers to the N2 type truck with the maximum total design mass not greater than 4.5 tons in the N type trucks in the vehicle type classification. The light truck body is smaller than a large truck, so that the light truck has the flexibility, and can transport small-tonnage goods, so that the light truck is widely applied to the transportation industry. The suspension spring of the light truck is an elastic element in the automobile suspension, so that the light truck axle and the light truck frame or the automobile body are in elastic connection, vertical load is borne and transmitted, and impact caused by uneven road surfaces is relieved and restrained.
The traditional rear longitudinal composite steel plate spring suspension system is usually a secondary rigidity main and auxiliary spring structure, the auxiliary spring is arranged above or below the main spring, the main spring and the auxiliary spring are in contact and overlapped work through each plate spring, due to the influence of coulomb friction damping between the plates, friction work can cause that the equivalent dynamic rigidity and the design rigidity are difficult to predict and control, the dynamic-static ratio is often larger, particularly under the condition of empty and full load and small amplitude, the comfort of a flat road is influenced, and even the problem of low-frequency resonance occurs.
After all levels of leaf springs of the rear longitudinal composite steel plate spring suspension system are contacted, the full-load arc heights of all levels of leaf springs are different, so that a user is worried about bearing judgment. And each stage of plate spring leaf is contacted with the leaf under any working stroke among all the plate spring leaves of the traditional rear longitudinal composite steel plate spring suspension system, and the superposition stress generates dry friction exceeding the expectation, thereby influencing the smoothness.
Disclosure of Invention
The invention provides a design method of a rear plate spring with multi-level rigidity for a light truck, which can reduce the reliability risk of the design and enable the design of the rear plate spring with multi-level rigidity for the light truck to form industrialized application.
The parameters for the plate spring after the multi-stage rigidity of the light truck is calculated are configured and calculated, and the parameters comprise: wheelbase L, no-load offset frequency f k Full load offset frequency f m No load of axle G 1 Full load of axle G 2 The half-load axial load state is G 12 The second half-load state is G 23 Unsprung mass G of the rear axle m No-load unilateral spring load F k Half-load unilateral spring load F 12 Half-load unilateral spring load F 23 Full load single side spring load F m And the limit distance delta between the first sheet of the no-load auxiliary spring and the corresponding cantilever 1 (the limiting distance is designed by combining the standard deviation of the dynamic deflection and the required collision limiting probability of the vehicle running working condition with a normal distribution table).
The design process involves the main reed length L Master and slave (ii) a Minor piece length L f1 Length of sub n sheets L fn And n is a positive integer. Clamping distance L Clip Beta clamping null factor, main spring eye end thickness h ZD Root thickness h of main spring ZG Thickness h of the minor end FD1 Thickness h of the secondary root FG1 …, minor n-end thickness h FDn Thickness h of auxiliary n root FGn 。
The method for designing and calculating the main spring parameters comprises the following steps:
s101: by design input of no-load offset frequency f k And no-load spring load F k Determining main spring clamping stiffness C Master and slave Calculated by applying the following formula
The unilateral spring load is half of the axle load without the unsprung load, and the computation of the unilateral spring load in other states is the same as the formula.
C Master and slave ＝(2πf k ) 2 F k
S102: main leaf length L Master and slave The length L of the main reed of the rear suspension of the general N2 type vehicle is determined by the wheel base L Main Selected within the following ranges
0.35L≤L Main ≤0.4L
Length L of main reed of N3 type vehicle rear suspension Main Selected within the following ranges
0.25L≤L Main ≤0.35L
S103: the width b of each sheet of the step spring suspension system is the same, the widths of N2 sheets are generally 70mm and 75mm, the widths of N3 sheets are generally 75mm and 90mm
S104: according to the requirement of the technical condition of the plate spring on the fatigue life, the main spring has less specific stress of the plate spring
Should meet the following range
S105: the limit travel H of the plate spring is determined by the following formula according to the requirement of yield stress in the technical condition of the plate spring material
Wherein delta s The yield limit of the material and mu as the safety coefficient are generally 1.1
S106: the plate spring can be bent in use, the arc height can be attenuated along with the use time, and a certain full-load arc height f is often set for preventing the phenomenon of reverse bow under the full-load static load of the plate spring a The full load arc height is generally taken
10mm≤f a ≤20mm
S107: static deflection of main spring is f c Dynamic deflection of f d The static deflection is the deformation from full load, and the dynamic deflection is the deformation from full load to limit inverse arch. The two parameters satisfy the following formula:
wherein alpha is more than or equal to 5 and less than or equal to 6
Main spring arc height H Master and slave (Main spring design flattening arc height, not considering the form of the eye) is determined by the following formula
H Main ＝f c +f a
S108: by full load spring load F m Effective length l of plate spring e Specific stress of main spring
Calculating the thickness h of the root of the plate spring ZG For light weight maximum effect design, the thickness is generally rounded up and the smallest integer is taken. The calculation formula is as follows:
wherein L is e ＝L Master and slave -β·L Clip
Beta is a clamping ineffective coefficient; l is Clip Clamping distance for plate spring
S109: because the two ends of the main spring are provided with the rolling lug structures, the rolling lug end of the main spring is required to bear the function of transmitting longitudinal force except for vertical support, the general rear axle is a drive axle, the maximum stress of the front half section of the main spring of the plate spring under the working condition of maximum driving force is checked, the stress is required to be not more than 350MPa, the specific calculation formula can refer to automobile chassis design, and the thickness h of the end part of the rolling lug of the main spring is determined from the stress ZD For light weight design, the minimum end thickness is generally chosen to meet the stress conditions.
In conclusion, the main spring rigidity C meeting the design requirements is obtained by adjusting the length of the straight section of the coil end through the existing mature parabolic structure design method of the few-leaf spring Master and slave 。
The method for designing and calculating the parameters of each leaf of the auxiliary spring comprises the following steps:
s201: and (3) designing the rigidity of the assembly: full-load offset frequency f from design input m And full load spring load F m Determining the clamping stiffness C of the assembly General assembly Calculated using the following formula
C General assembly ＝(2πf m ) 2 F m
Wherein C is General assembly ＝C Master and slave +C f1 +C f2 +…+C fn
C f1 Clamping rigidity of the first plate of the auxiliary spring from bottom to top, C fn Clamping rigidity for nth piece of auxiliary spring from bottom to top
S202: designing the arc height of each piece: leaf spring is unloadedUnder the load state, the distance between the first auxiliary spring piece and the corresponding first auxiliary spring piece limiting cantilever is delta 1 The distance between the second piece of the auxiliary spring and the corresponding second piece of the auxiliary spring limiting cantilever is delta 2 The distance between the nth piece of the auxiliary spring and the nth piece of the corresponding auxiliary spring limiting cantilever is delta n In order to realize that the arc heights of all the plate spring pieces are consistent when all the plate spring pieces work simultaneously or the last piece of the auxiliary spring just acts, namely all the plate spring pieces have the same full-load arc height, the limit distance of each cantilever auxiliary spring and the arc height of each auxiliary spring piece have the following relations:
wherein H f1 Designing arc height for the first leaf of the auxiliary spring, H fn And designing the arc height for the nth piece of the auxiliary spring, wherein the arc height is the variable quantity from the free state of the plate spring to the flattening state. H 0 The variation of arc height in the no-load state of the main spring, H 0 ＝F k ·g/c Master and slave 。
And determining the cantilever limiting distance between the auxiliary spring and the corresponding auxiliary spring: delta 1 The standard deviation of dynamic deflection and the required collision limit probability under the operating condition of the vehicle are combined with a normal distribution table to design the limit distance, and 8-10mm is recommended for a good road surface. Delta 2 ...Δ n The following relationship is required:
wherein F 12 、F 23 The concerned load in the use state of the plate spring is respectively a design input, and generally does not exceed two states, such as a half-load state, in the state, the auxiliary spring of the plate spring assembly does not contact with the cantilever of the corresponding auxiliary spring, and the plate spring assembly is different from the traditional two-stage spring and even a single plate spring, so that the rigidity and the offset frequency in the specific state can be effectively reduced, and the comfort is improved. Because the main spring is a single-piece spring, in order to avoid driving risk caused by overlarge full-load stress of the main spring, the recommended value is delta less than or equal to 5mm n+1 -Δ n ≤10mm。
S203: the rigidity of each leaf of the auxiliary spring is designed as follows:
C f3 can be obtained by the formula in step S201.
S204: the length of each leaf of the auxiliary spring is designed as follows:
the lengths of the auxiliary springs are gradually reduced from bottom to top, the lengths of the auxiliary springs are as long as possible, and under the working condition of the same bounce amount, the length of the plate spring is long, the smaller the curvature change is, the smaller the stress change is, and the longer the service life of the plate spring is.
The length of the first sheet of the auxiliary spring cannot be too long, and L is recommended to ensure the vertical movement with the front and rear plate spring supports of the main spring and the movement space under the braking torsion in the movement process Main -L f1 Is more than or equal to 350mm. The adjacent difference values of the lengths of the auxiliary springs are the same, delta L is recommended to be more than or equal to 100mm and less than or equal to 150mm, the invalid lengths at the two ends of the auxiliary springs are set to be the same, the invalid lengths mainly ensure that the plate spring is subjected to vertical motion deformation and always contacts with a corresponding auxiliary spring cantilever under longitudinal torsion, the invalid lengths avoid that the plate spring is completely separated under full load working conditions, and motion check is based on finite element simulation. Recommend one-sided invalid length [30,40]。
S205: the thickness of each leaf of the auxiliary spring is designed as follows:
in order to reduce dry friction with a cantilever of a corresponding auxiliary spring, reduce the dynamic-static ratio and improve the smoothness in the design of the auxiliary spring of the multi-stage rigidity stepped plate spring, holes are dug in effective length points of each auxiliary spring, embedded nylon gaskets are assembled, the friction coefficient can be reduced from 0.3-0.5 to 0.1-0.15, and the thicknesses of the end parts are set to be consistent for the purpose of the nylon gaskets.
The multistage rigidity stepped plate spring is in contact with the corresponding auxiliary spring cantilever step by step from the main spring to each auxiliary spring upwards in the horizontal jumping motion, the main spring works in a load mode all the time, the working frequency of each stage of auxiliary spring is gradually decreased, the acting frequency of the uppermost end auxiliary spring is lowest, for the purpose, the specific stress of each stage of plate spring is sequentially improved from bottom to top, and the service life of the assembly is controllable on the premise that the plate spring length is shortened step by step and the rigidity meets the S203 design value. The larger the specific stress is, the larger the unit deformation stress change is, the shorter the service life of the plate spring is, the service life is designed according to the use frequency, and the aims of reducing the redundant structure and designing in a light weight mode are fulfilled.
Recommended value of auxiliary spring specific stress of each piece (the auxiliary spring specific stress should not be more than 25MPa/mm, so as to limit the number of auxiliary springs):
the auxiliary spring first plate: delta is not less than 12 f1 ≤15(MPa/mm)
Auxiliary spring second leaf: delta is more than or equal to 16 f2 ≤19(MPa/mm)
The auxiliary spring third leaf: delta is more than or equal to 20 f3 ≤23(MPa/mm)
……
According to the recommended value of the specific stress, the root thickness of each leaf auxiliary spring can be calculated. The rigidity of each level of auxiliary spring meeting the design requirements is obtained by adjusting the length of the straight section of the end part through the existing mature parabolic structure design method of the few-leaf spring.
The method for designing and calculating the parameters of the cushion blocks between the reeds comprises the following steps:
because the variable cross section parabola structure of each piece is designed, if no cushion block exists between the pieces, the rest pieces are not contacted except the contact of the flat section of the root part, and the length of each piece of the auxiliary spring is gradually reduced, the arc height is the same, the curvature radius is reduced, and the tail end gap between the adjacent pieces is reduced until the contact interference is possible. In order to avoid dry friction caused by contact interference and influence smoothness, the cushion blocks between the sheets need to meet the following requirements:
H inverse direction ＝H-H Master and slave
Wherein H Inverse direction The change of the arc height from the flattening of the main spring to the limit of the reverse bow;
wherein h is Master and slave The thickness of a cushion block between the main spring and the first sheet of the auxiliary spring is set;
wherein h is 1 The thickness of the cushion block between the first auxiliary spring sheet and the second auxiliary spring sheet is set;
wherein h is (n-1) The thickness of a cushion block between the nth sheet of the auxiliary spring and the (n-1) th sheet of the auxiliary spring is set;
wherein R is f1 Is a reverse bow H of the first leaf of the auxiliary spring Inverse direction The latter radius of curvature;
wherein R is fn Is a reverse bow H of the first leaf of the auxiliary spring Inverse direction The latter radius of curvature.
According to the technical scheme, the invention has the following advantages:
the design method of the multi-level-rigidity rear plate spring of the light truck solves the problems that the traditional rear longitudinal composite plate spring suspension system is usually in a two-level-rigidity main and auxiliary spring structure, the auxiliary spring is arranged above or below the main spring, and the main spring and the auxiliary spring are in contact and overlapped work by each plate spring piece, so that the Coulomb friction damping between the pieces is influenced, and the equivalent dynamic rigidity and the design rigidity are difficult to predict and control. By the aid of the device and the method, full-load arc heights of all levels of leaf springs can be the same after all levels of leaf springs are completely contacted, and users are prevented from worrying about bearing judgment. The invention can avoid the contact of each level of leaf spring without sheet and sheet under any working stroke between each leaf spring, and avoid the influence of dry friction exceeding the expected caused by the superposition stress on the smoothness.
The invention combines the non-overlapping contact between the sheets of the multi-stage rigidity plate spring, the sheet length of each sheet is gradually reduced from bottom to top, the main spring fixes the plate spring eye and the bracket through the plate spring pin to realize the hinge, each auxiliary spring is matched with the cantilever bracket arranged on the frame to realize the step-by-step contact of each sheet of auxiliary spring, the multi-stage nonlinear elastic characteristic curve is realized, and the invention is suitable for the comfort improvement under various loads.
The design method of the multi-stage rigidity rear plate spring of the light truck can ensure that the rigidity of each plate spring meets the comfort requirement of each bearing state; the service life of each plate spring can be ensured to meet the requirement of fatigue times of the rack; the arc height of each plate spring is set to meet the requirement that the full-load arc height of each plate spring is consistent in a full-load state, and the arrangement of the cushion blocks between the auxiliary spring cantilever support and the plate springs is guaranteed to avoid plate spring limit jumping without inter-plate contact. The design method of the rear plate spring with the multi-level rigidity of the light truck ensures the smoothness and reliability of the design of the light truck.
And the invention can calculate the performance parameters such as the structure size and rigidity of each stage according to the requirements of smoothness deviation frequency and bearing, and simultaneously ensure that the service life of each stage of plate spring is designed according to the descending of the use frequency from bottom to top.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a flow chart of a design method of a rear plate spring with multi-level rigidity for a light truck;
FIG. 2 is a schematic diagram of the spring characteristic of a leaf spring after multi-level stiffness is designed;
fig. 3 is a schematic structural view of the rear plate spring designed to correspond to multiple levels of stiffness.
In fig. 3, 1 is the first leaf of the main spring; 2, a first leaf of the auxiliary spring; 3, a second spring sheet; 4, third piece of auxiliary spring; 5, a main spring and auxiliary spring first sheet cushion block; 6, a cushion block between the first auxiliary spring piece and the second auxiliary spring piece; 7, a cushion block between the second auxiliary spring piece and the third auxiliary spring piece; 8 is main spring arc height; 9, limiting the spacing between the first piece of the auxiliary spring and the corresponding cantilever; 10 the first piece of the auxiliary spring corresponds to the cantilever; 11 the second leaf of the auxiliary spring corresponds to the cantilever; the third piece of the 12 auxiliary springs corresponds to the cantilever; 13 the first arc height of the auxiliary spring; 14, the effective length of the third piece of the auxiliary spring; 15 main spring length.
Detailed Description
As shown in fig. 1 to 3, the plate spring designed by the method for designing the rear plate spring with multi-level stiffness for the light truck is applied to the rear suspension of the longitudinally-arranged plate spring non-independent suspension, and the plate spring serves as an elastic unit to achieve the effect of buffering vibration and has the functions of guiding and axle positioning.
The design method is applied to symmetrical plate springs and structures with equal length on the left and the right; the plate spring can also be applied to a plate spring with equal width and a structure with equal width of each plate; the invention relates to a plate spring which is a multi-stage rigidity plate spring, and the rigidity of each stage is realized by a single plate spring.
Before design, the invention configures the following parameters in advance: wheelbase L, no-load offset frequency f k Full load offset frequency f m No load axle load G 1 Full load of axle load G 2 The half-load axle load state one is G 12 The second half-load state is G 23 Unsprung mass G of the rear axle m No-load unilateral spring load F k Half-load unilateral spring load F 12 Half-load unilateral spring load F 23 Full load single side spring load F m Spacing distance delta between first sheet of no-load auxiliary spring and corresponding cantilever 1 (limit distance is designed by combining the standard deviation of dynamic deflection and the required collision limit probability under the vehicle running working condition with a normal distribution table).
The design process involves the main reed length L Main (ii) a Length of secondary sheet L f1 Length of sub n sheets L fn And n is a positive integer. Clamping distance L Clip Beta clamping null factor, main spring eye end thickness h ZD Thickness h of main spring root ZG Thickness h of the secondary end FD1 Thickness h of the secondary root FG1 …, minor n-end thickness h FDn Thickness h of auxiliary n root FGn 。
The design method of the rear plate spring with the multilevel rigidity for the light truck can acquire and process associated data based on an artificial intelligence technology. The intelligent diagnosis method of the numerical control machine driven by the digital twin simulates, extends and expands the intelligence of people by using a digital computer or a machine controlled by the digital computer, senses the environment, acquires knowledge and uses the knowledge to acquire the theory, method, technology and application device of the best result. The method also has a machine learning function, wherein the machine learning and the deep learning in the method generally comprise the technologies of artificial neural network, belief network, reinforcement learning, transfer learning, inductive learning, formal education learning and the like.
The design method of the rear plate spring with the multilevel rigidity for the light truck is applied to one or more design terminals, wherein the design terminals are equipment capable of automatically performing numerical calculation and/or information processing according to preset or stored instructions, and hardware of the design terminals comprises but is not limited to a microprocessor, an Application Specific Integrated Circuit (ASIC), a Programmable Gate Array (FPGA), a Digital Signal Processor (DSP), embedded equipment and the like.
The design terminal may be any electronic product capable of performing human-computer interaction with a user, for example, a Personal computer, a tablet computer, a smart phone, a Personal Digital Assistant (PDA), an interactive Internet Protocol Television (IPTV), and the like.
The design terminal may also include network equipment and/or user equipment. The network device includes, but is not limited to, a single network server, a server group consisting of a plurality of network servers, or a Cloud Computing (Cloud Computing) based Cloud consisting of a large number of hosts or network servers.
The Network where the terminal is designed to be located includes, but is not limited to, the internet, a wide area Network, a metropolitan area Network, a local area Network, a Virtual Private Network (VPN), and the like.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The present invention will be described in further detail below by way of examples.
1. The vehicle is a light blue-brand truck, the wheelbase L =3280mm, the unloaded rear axle load G1=1178kg, the rear axle half-load state G12=1728kg, the rear axle half-load state two G23=2426kg, the fully loaded rear axle load G2=5747kg, the unsprung load Gm =458kg, the unloaded offset frequency fk =3.02Hz, the fully loaded offset frequency fm =2.6Hz, and the plate spring clamping distance L clamp =150mm.
According to the analysis and setting of the vehicle market and application scenes, the limit distance delta between the first sheet of the no-load auxiliary spring and the corresponding cantilever is set 1 =9mm. Four levels of stiffness can be achieved by four leaf springs, for a total of four load-bearing states of interest.
2. The clamping rigidity of the main spring is calculated, only the main spring acts in the no-load state, and the no-load unilateral spring load
C Master and slave ＝(2πf k ) 2 F k ＝130N/mm。
3. The wheel base of the vehicle is L =3280mm, and the range of the wheel base is more than or equal to 0.35L Master and slave Less than or equal to 0.4L, 1148mm less than or equal to L Master and slave Less than or equal to 1312mm, the longer the leaf length, the better reliability can be obtained, and the length L of the main leaf spring is selected by rounding Master and slave ＝1300mm。
4. The total mass of the light blue truck does not exceed 4.5T, and the conventional width b of the plate spring is 70mm.
5. According to less specific stress of main spring
The main spring is made of common spring steel, the yield strength is 1200MPa, the safety coefficient mu is more than or equal to 1.1, and the limit stroke of the plate spring is greater than or equal to>
The limit travel H of the band spring is 115mm.
6. And calculating the full-load static deflection fc and the plate spring dynamic deflection fd by a calculation formula of the full-load static deflection fc.
7. Main spring design arc height H Master and slave ＝f c +f a Wherein f is more than or equal to 10mm a ≤20，f a Is full load arc height, f a =15mm, then H Main =85mm, the design arc height does not take into account the main spring eye form.
8. Calculating the effective length of the main spring: l is a radical of an alcohol e ＝L Main -β·L Clip Wherein beta is a clamping ineffective coefficient and is taken as 0.5;
l splint spring clamping distance L clamp =150mm, namely L e Equation of substitution of =1225mm
The root thickness h of the main spring can be calculated ZG Not less than 19.9mm, taking the whole and then taking h ZG ＝20mm。
9. The method is characterized in that the existing mature design method is adopted, the rear axle is a drive axle, the maximum stress of the front half section of the main spring of the plate spring under the working condition of the maximum driving force is checked, the stress is not more than 350MPa, and the end thickness h of the plate spring can be determined ZD ＝11mm。
From the above calculated data, the full load stress of the full load main spring can be calculated as
And basically meets the requirement of full load stress of the main spring.
Other parameters of the main spring can be calculated by a few-leaf variable cross section maturation method in the chassis design.
10. The frequency of the single-side spring load is increased by the conditions that the full-load offset frequency Fm =2.6Hz, the full-load single-side spring load Fm =2644..5kg,
the clamping rigidity C of the plate spring assembly can be calculated by the following formula General (1) ＝(2πf m ) 2 F m ＝705N/mm。
11. According to H Master and slave ＝85mm，Δ 1 ＝9mm，H 0 ＝F k ·g/C Master and slave ＝27mm，
By H f1 ＝H Main -H 0 -Δ 1 The design arc height H of the first leaf of the auxiliary spring can be calculated f1 ＝49mm。
By H fn ＝H Main -H 0 -Δ n
12. From G12=1728kg, F12=635kg; from G23=2426kg, F23=984kg is known. By the formula
(H 0 +Δ 1 )·C Master and slave ≤F 12 ·g≤(H 0 +Δ 1 )·C Master and slave +(Δ 2 -Δ 1 )·(C Master and slave +C f1 )
Calculating Delta 2 -Δ 1 ≥4mm，
13. By
(H 0 +Δ 1 )·C Master and slave +(Δ 2 -Δ 1 )·(C Master and slave +C f1 )≤F 23 ·g≤(H 0 +Δ 1 )·C Master and slave +(Δ 2 -Δ 1 )·(C Master and slave +C f1 )+(Δ 3 -Δ 2 -Δ 1 )·(C Master and slave +C f1 +C f2 )
Can calculate Delta 2 -Δ 1 ≤13mm。
By recommending 5mm ≦ Δ n+1 -Δ n Less than or equal to 10mm, and delta meeting the requirement can be selected 2 ＝16mm；Δ 3 ＝23mm。
14. The length of each leaf of the auxiliary spring can be determined by L Master and slave -L f1 Not less than 350mm, wherein L Master and slave =1300mm, the effective length L of the first leaf of the auxiliary spring can be selected f1 Is not less than 1000mm, the effective length L of the second leaf of the auxiliary spring can be selected by the value that Delta L is not less than 100mm and not more than 150mm f2 =870mm, effective length L of third leaf of auxiliary spring f3 =870mm, from unilateral ineffective length 30,40]The preferred extension lengths of the respective pieces of the auxiliary spring are 1080mm,930mm and 800mm, respectively.
15. Selecting the specific stress of each auxiliary spring to be 13.5MPa/mm in sequence according to the recommended specific stress value of each auxiliary spring; 17.5MPa/mm;21MPa/mm.
From step 8
The root thickness h of each auxiliary spring can be determined ZGn Is the thickness of the root of the nth leaf of the auxiliary spring, L en Is the effective length of the nth part of the auxiliary spring>
The specific stress of the nth piece of the auxiliary spring.
The root thickness of each leaf of the auxiliary spring can be selected to be 20mm,14mm and 10mm.
The thicknesses of the end parts of the auxiliary springs are the same and can be selected to be 8mm. The rigidity of each stage of the auxiliary spring obtained by calculation can be obtained by adjusting the length of the straight section of the end part through the existing mature design method of the plate spring with less leaf springs and variable cross section.
16. According to H Inverse direction ＝H-H Master and slave Wherein H =115mm Master and slave H can be calculated as H by 85mm Inverse direction ＝30mm。
By
R can be calculated Master and slave ＝7042mm。
By the formula
Wherein the thickness h of the root of the first leaf of the auxiliary spring FG1 =20mm, thickness h of first leaf end of auxiliary spring FD1 =8mm, the thickness h of the spacer between the main spring and the auxiliary spring is known Master and slave ≥5.25mm。
By the formula
Wherein->
R f1 =4167mm, auxiliary spring second piece root thickness h FG2 =14mm, end thickness h of second leaf of auxiliary spring FD2 =8mm, the thicknesses h of the first and second pads of the auxiliary spring 1 ≥6.3mm。
By the formula
Wherein +>
R f2 =3154mm, thickness h of third leaf root of auxiliary spring FG3 =10mm, end thickness h of third leaf of auxiliary spring FD3 =8mm, the thickness h of the second pad and the third pad of the auxiliary spring is known 2 ≥11.3mm。
The structural design of the multi-stage rigidity leaf spring of the light truck can be determined after the design calculation is completed, and the weight is the lightest while the design input bearing and performance requirements can be ensured according to the leaf spring calculated in the steps.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
The method can collect the design parameters of the multi-level rigidity rear plate spring of the light truck, is convenient for designers to carry out increasing, deleting, modifying and checking operations, effectively adjusts the data of the design process, meets the design requirements and improves the design efficiency. Design parameters can be efficiently collected, stored and processed, the design process of the plate spring can be monitored based on the multi-level rigidity of the light truck and the whole design process can be described by using a multi-dimensional space. The design precision is improved, the abnormal problems in the design process are found in time and are adjusted, so that the level and the efficiency of the design process are improved, the risk of the design process is controlled, and the timeliness and the scientificity of supervision, management and control of the whole design process are realized.
The units and algorithm steps of each example described in the embodiment disclosed in the method for designing the rear leaf spring with multi-level rigidity for the light truck provided by the invention can be realized by electronic hardware, computer software or a combination of the electronic hardware and the computer software, and in order to clearly illustrate the interchangeability of the hardware and the software, the components and the steps of each example are generally described according to functions in the above description. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the method of designing a multi-level stiffness rear leaf spring for a pick-up truck according to the present invention, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one type of logical functional division, and other divisions may be realized in practice, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may also be an electric, mechanical or other form of connection.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, devices, steps, and so forth. In other instances, well-known methods, devices, implementations or operations have not been shown or described in detail to avoid obscuring aspects of the invention.
In the light truck multi-level stiffness rear leaf spring design method, computer program code for carrying out operations of the present disclosure may be written in one or more programming languages, including but not limited to an object oriented programming language such as Java, smalltalk, C + +, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or power server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A design method for a rear plate spring with multi-level rigidity of a light truck is characterized by comprising the following steps:
s1, configuring and calculating parameters for the rear plate spring with the multi-stage rigidity of the light truck, wherein the parameters comprise: wheelbase L, no-load offset frequency f k Full load offset frequency f m No load of axle G 1 Full load of axle G 2 The half-load axial load state is G 12 The half-load shaft load state is G 23 Unsprung mass G of the rear axle m No-load single-side spring load F k Half-load unilateral spring load F 12 Half-load unilateral spring load F 23 Full load single side spring load F m And the limit distance delta between the first sheet of the no-load auxiliary spring and the corresponding cantilever 1 ；
S2, designing and calculating main spring parameters;
s3, designing and calculating parameters of each auxiliary spring;
and S4, designing and calculating parameters of the cushion blocks between the reeds to obtain the leaf spring of the light truck.
2. The design method of the rear leaf spring with multi-level stiffness for the light truck as claimed in claim 1, wherein the design and calculation method of the main spring parameters comprises the following steps:
s101: obtaining the no-load offset frequency f k Respectively calculating the no-load spring load F by the following formula k And main spring clamping rigidity C Main ；
C Master and slave ＝(2πf k ) 2 F k
S102: main reed length L Master and slave The length L of the main reed of the rear suspension of the N2 type vehicle is determined by the wheel base L Master and slave Selected within the following ranges
0.35L≤L Master and slave ≤0.4L
Length L of main reed of N3 type vehicle rear suspension Master and slave Selected within the following ranges
0.25L≤L Master and slave ≤0.35L。
3. The design method of multi-level stiffness rear leaf spring of a light truck according to claim 2,
s103: the widths b of all the sheets of the step spring suspension system are the same, the widths of N2 sheets are 70mm and 75mm, and the widths of N3 sheets are 75mm and 90mm;
s104: main spring less leaf spring specific stress
In accordance with the following range；
S105: the limit travel H of the leaf spring is determined by the following formula
Wherein delta s 1.1 is taken as the yield limit of the material and mu is the safety coefficient.
4. The design method of multi-level stiffness rear leaf spring of a pickup truck according to claim 3,
s106: setting full load arc height f a Full load arc height
10mm≤f a ≤20mm
S107: static deflection of main spring of f c Dynamic deflection of f d The static deflection is the deformation from full load, and the dynamic deflection is the deformation from full load to limit inverse bow; the two parameters satisfy the following formula:
wherein alpha is more than or equal to 5 and less than or equal to 6
Main spring arc height H Master and slave Calculated by the following formula
H Master and slave ＝f c +f a
S108: by full load spring load F m Effective length l of plate spring e Specific stress of main spring
Calculating the thickness h of the root of the plate spring ZG The calculation formula is as follows:
wherein L is e ＝L Master and slave -β·L Clip
Beta is a clamping ineffective coefficient; l is Clamp The clamping distance of the plate spring is adopted.
5. The design method of multi-level stiffness rear leaf spring of a light truck according to claim 4,
s109: checking the maximum stress of the front half section of the main spring of the plate spring under the working condition of the maximum driving force, wherein the maximum stress is not more than 350MPa, and determining the thickness h of the end part of the main spring eye ZD Selecting the minimum end thickness value meeting the stress condition; adjusting the length of the flat section at the end of the rolling lug to obtain the rigidity C of the main spring meeting the design requirement Master and slave 。
6. The design method of the rear leaf spring with multi-level stiffness of the light truck as claimed in claim 1 or 2, wherein the manner of designing and calculating each parameter of the auxiliary spring comprises the following steps:
s201: designing the rigidity of the assembly: input full load offset frequency f m And full load spring load F m Determining the clamping stiffness C of the assembly General assembly Is calculated by the following formula
C General assembly ＝(2πf m ) 2 F m
Wherein C is General assembly ＝C Master and slave +C f1 +C f2 +…+C fn
C f1 Clamping rigidity of the first plate of the auxiliary spring from bottom to top, C fn The clamping rigidity of the nth piece of the auxiliary spring from bottom to top is provided;
s202: designing the arc height of each piece: under the no-load state of the plate spring, the distance between the first auxiliary spring piece and the corresponding first auxiliary spring piece limiting cantilever is delta 1 The distance between the second piece of the auxiliary spring and the limit cantilever corresponding to the second piece of the auxiliary spring is delta 2 The distance between the nth piece of the auxiliary spring and the nth piece of the corresponding auxiliary spring limiting cantilever is delta n ；
Each piece all has the same full-load camber, and spacing distance of each cantilever auxiliary spring and each piece camber of auxiliary spring have the following relation:
wherein H f1 Designing arc height for first leaf of auxiliary spring H fn Designing the arc height for the nth piece of the auxiliary spring, wherein the arc height is the variable quantity of the arc height from the free state of the plate spring to the flattening state; h 0 Is the arc height variation of main spring in no-load state, H 0 ＝F k ·g/C Master and slave ；
The auxiliary spring and the corresponding auxiliary spring cantilever limit distance are determined: delta 1 Taking 8-10mm;
Δ 2 ...Δ n the following relationship is satisfied:
wherein F 12 、F 23 The load of interest in the use state of the leaf spring;
5mm≤Δ n+1 -Δ n ≤10mm。
7. the design method of multi-level stiffness rear leaf spring of a light truck according to claim 6,
s203: designing stiffness parameters of each leaf of the auxiliary spring:
C f3 the formula (2.1) is used for simultaneous calculation;
s204: designing the length of each leaf of the auxiliary spring:
the length of the first leaf of the auxiliary spring is L Main -L f1 ≥350mm；
The length adjacent difference value of each leaf between the auxiliary springs is 100mm or more and delta L or less and 150mm or less;
one-sided invalid length [30,40].
8. The design method of multi-level stiffness rear leaf spring of a light truck according to claim 7,
s205: designing the thickness of each leaf of the auxiliary spring:
the recommended value of the specific stress of each auxiliary spring is as follows:
first leaf of auxiliary spring: delta is not less than 12 f1 ≤15(MPa/mm)
Auxiliary spring second leaf: delta is more than or equal to 16 f2 ≤19(MPa/mm)
Auxiliary spring third leaf: delta of not less than 20 f3 ≤23(MPa/mm)
……
And calculating the root thickness of each leaf auxiliary spring according to the recommended specific stress value.
9. The design method of multi-level stiffness rear leaf spring of a light truck according to claim 1 or 2,
the method for designing and calculating the parameters of the cushion blocks between the reeds comprises the following steps:
H inverse direction ＝H-H Master and slave
Wherein H Inverse direction The change of the arc height from the flattening of the main spring to the limit of the reverse bow;
wherein h is Master and slave The thickness of a cushion block between the main spring and the first sheet of the auxiliary spring is set;
wherein h is 1 The thickness of the cushion block between the first auxiliary spring sheet and the second auxiliary spring sheet is set;
wherein h is (n-1) The thickness of a cushion block between the nth sheet of the auxiliary spring and the (n-1) th sheet of the auxiliary spring is set;
wherein R is f1 Is a reverse bow H of the first leaf of the auxiliary spring Inverse direction The latter radius of curvature;
wherein R is fn Is a reverse bow H of the first leaf of the auxiliary spring Inverse direction The latter radius of curvature.
10. A design terminal comprising a memory, a processor and a computer program stored on said memory and executable on said processor, wherein said processor when executing said program performs the steps of the multi-stiffness rear leaf spring design method of a pickup truck as claimed in any one of claims 1 to 9.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116839783A (en) * | 2023-09-01 | 2023-10-03 | 华东交通大学 | Method for measuring stress value and deformation of automobile leaf spring based on machine learning |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116839783A (en) * | 2023-09-01 | 2023-10-03 | 华东交通大学 | Method for measuring stress value and deformation of automobile leaf spring based on machine learning |
| CN116839783B (en) * | 2023-09-01 | 2023-12-08 | 华东交通大学 | Method for measuring stress value and deformation of automobile leaf spring based on machine learning |
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