CN106874608A - A kind of leaf spring made of steel plate method for designing - Google Patents

Abstract

The invention discloses a kind of method for designing of leaf spring made of steel plate, described its end of leaf spring made of steel plate and root is equal thickness section, and its end changes with root centre position section thickness according to parabola rule；According to the requirement of parabola leaf spring iso-stress, principle at parabola according to iso-stress is determined into each position leaf spring thickness, and thickness can be exported according to different step-lengths, then according to calculating plate spring shape under the conditions of iso-stress, the rigidity of leaf spring is calculated, whether design requirement is met finally according to offset frequency requirement inspection rigidity of plate spring.The present invention provides a kind of convenient, accurate computational methods for the design of few piece parabola leaf spring, it is easy to operate, calculating process is fast, computational accuracy is high, output result facilitates Instructing manufacture and the examination and test of products.

Description

A kind of leaf spring made of steel plate method for designing

Technical field

The present invention relates to a kind of method for designing of leaf spring made of steel plate, belong to leaf springs of car suspension technical field.

Background technology

In the method for designing of existing leaf spring made of steel plate, known technology is that truck leaf spring uses methods of mechanics The simplified formula of derivation is not suitable for the design meter of parabola leaf spring, it is necessary to using correction factor corrected Calculation result, error is larger Calculate, and calculating process is cumbersome, is not suitable for application；Some use FInite Element designs are calculated, and it is set up model and is difficult and designs Product is consistent, causes calculation error.So existing design and calculation method error is larger, and it is difficult to determine the scope of error.

The content of the invention

The technical problems to be solved by the invention are directed to the defect of prior art presence, there is provided a kind of quickly, accurately to set The method for counting parabola leaf spring.

To solve this technical problem, the invention provides a kind of method for designing of leaf spring made of steel plate, described throwing Its end of thing line leaf spring is equal thickness section with root, and its end is with root centre position section thickness according to para-curve gauge Rule change；According to the requirement of parabola leaf spring iso-stress, the principle at parabola according to iso-stress is determined into each position leaf spring Thickness, and thickness can be exported according to different step-lengths, then according to plate spring shape is calculated under the conditions of iso-stress, calculate Go out the rigidity of leaf spring, whether design requirement is met finally according to offset frequency requirement inspection rigidity of plate spring, specifically include following steps：

1) basic parameter is determined first, including bears load p₁, leaf spring width b, effective length L, straight segment length C, end Portion's thickness F, parabola rest position L₁.Few each of leaf spring is born load and is directly proportional to the size of each rigidity, the load of each Easily obtain, few leaf spring assembly is the linear superposition of each single-leaf spring, symmetrical before and after the leaf spring that the present invention is calculated, so this It is related to load to be half leaf spring load P in invention₁Half leaf spring size is with length dimension.For by several plate spring sheet groups Into plate spring assembly can with it is of the invention design program repeat be calculated.

2) leaf spring stress σ sizes are determined according to material and use condition, determines leaf spring thickness h_xChanging Pattern.

h_xChanging Pattern is：

Wherein：X is that the distance away from centre bolt is put on leaf spring.

3) according to the leaf spring root thickness determined by experience and arrangement, the thickness in the parabola thickness by calculating Degree is consistent, and end thickness determines according in the first step, so the actual knot of leaf spring can be determined according to x different spans Structure, leaf spring thickness h_xA series of Changing Patterns, leaf spring thickness h are obtained with the value difference of x_xChanging Pattern with x is：

According to design required precision and actual production in leaf spring rolling accuracy, x is taken a determining deviation it is a series of from Dispersion point, can obtain corresponding some strake spring thickness values h_xDiscretization point.By leaf spring thickness value h_xDiscretization point from calculate journey The shape of the leaf spring for just having obtained being actually needed rolling is exported in sequence.

4) the leaf spring thickness h being calculated using previous step_x, cantilever beam deformation side is asked for integration method according in mechanics Method, calculates leaf spring deflection, and wherein coefficient is obtained according to the continuity hypothesis of fine strain of millet.

Wherein：

The rigidity of leaf spring can be calculated according to following formula：

5) requirement according to vehicle for suspension offset frequency, it is determined that under the conditions of selected iso-stress, whether rigidity meets the requirements. The computing formula of offset frequency is calculated according to the following formula：

Beneficial effect：The present invention expresses the practical structures of leaf spring using the form of piecewise function, can be conveniently sharp The discretization data of parabola leaf spring are obtained with different required precisions, it is quick in the case where only initial design parameters are known to obtain To the concrete shape of parabola leaf spring；The rigidity of leaf spring is sought the piecewise function expression formula of practical structures using integration method, is eliminated The calculation error brought to parabolical simplification, improves design computational accuracy.The present invention is few piece parabola leaf spring Design provides a kind of convenient, accurate computational methods, it is easy to operate, calculating process is fast, computational accuracy is high, output result is convenient Instructing manufacture and the examination and test of products.

Brief description of the drawings

Fig. 1 is FB(flow block) of the invention；

Fig. 2 is the two panels parabola plate spring structure schematic diagram of the embodiment of the present invention one；

Fig. 3 is three leaf spring assembly structure schematic diagrames of the embodiment of the present invention two.

In figure：1 grasswort, 2 bag ears, 3 First Transition regions, 4 second transitional regions.

Specific embodiment

Below in conjunction with the accompanying drawings and embodiment is specifically described to the present invention.

Fig. 1 is FB(flow block) of the invention.

The present invention comprises the following steps：

(1) initial parameter determination is carried out to the leaf spring for needing Design vehicle suspension：Including bear load, leaf spring width, length, Clamp away from, the parameter such as root thickness, end thickness, parabola rest position；

(2) determine the stress of leaf spring using the requirement of material and operating mode according to leaf spring, calculated according to computing formula and answer waiting The thickness change rule of leaf spring under the conditions of power；

(3) the thickness change rule and primary condition according to iso-stress leaf spring determine the shape of iso-stress leaf spring, by plate The shape of spring is exported according to the form of constant spacing point；

(4) according to the parabola plate spring shape for calculating, rigidity of plate spring is calculated；

(5) whether properly the requirement according to suspension to offset frequency, check parabola leaf spring, if improper return second step, Stress intensity is redefined, to meet rigidity requirement；Designed if requirement is met and terminated；

Embodiment one

1. a two panels parabola leaf spring is designed, 38677N, half leaf spring load 9669N, leaf spring width 90mm, half is carried Piece effective length 900mm, half is straight segment length 90mm, end thickness 15mm, half parabola rest position 710mm.

2. leaf spring material be 51CrMoV4, using in cross-country operating mode, determine leaf spring stress be 500MPa.

Leaf spring thickness h_xChanging Pattern is：

3. the thickness expression formula of leaf spring practical structures is：

Expression formula can be obtained the x of series of discrete by the 50mm spacing for setting after determining, then obtain some row Leaf spring thickness h_xCentrifugal pump, finally exports these values, obtains carrying out the leaf spring thickness h of leaf spring rolling_xValue：

X distances	0	90	150	200	250	300	350	400	450	500	550	600	650	710	775	900
																	Thickness	37	37	33.7	32.5	31.3	29.9	28.6	27.1	25.6	24.1	22.4	20.7	18.8	16.3	15	15

4. according to leaf spring thickness h_xThe expression formula of practical structures, the computational methods according to mechanics can obtain rigidity of plate spring and be 149.5N/mm。

5. can determine that suspension offset frequency is according to rigidity of plate spring

Offset frequency is bigger than normal, does not meet the design requirement of suspension,

Repeat step 2, redefines leaf spring stress 615Mpa,

Repeat step 3, the leaf spring thickness h of output_xValue：

X distances	0	90	150	200	250	300	350	400	450	500	550	600	650	710	775	900
																		33	33	30.3	29.2	28.1	26.9	25.6	24.4	23	21.6	20.2	18.6	16.9	14.7	15	15

Repeat step 4, spring rigidity is 110N/mm.

Repeat step 5, suspension offset frequency is 1.70.

Offset frequency meets suspension design requirement, and design terminates.1/4 leaf spring can symmetrically be obtained into the sheet of rigidity identical two Reed, finally by the bending height h of grasswort 1, bag ear 2, First Transition region 3, the second transitional region 4 and transitional region₁Draw Go out, First Transition region 3, the second transitional region 4 are to be connected by straight line, and there is fillet R90 in First Transition region 3, just obtains Fig. 2 The two panels parabola plate spring structure of design.

Embodiment two

1. three parabola leaf springs are designed, 28174N is carried.First and second each carrying 9669N, leaf spring width 90mm, half effective length 900mm, half is straight segment length 90mm, end thickness 15mm, half parabola rest position 710mm；3rd carries 8836N, leaf spring width 90mm, half effective length 900mm, half is straight segment length 90mm, end Thickness 22mm, half parabola rest position 710mm；

2. leaf spring material is 51CrMoV4, determines that leaf spring stress is 615MPa.

3. the thickness expression formula of leaf spring practical structures is：

Expression formula can be obtained the x of series of discrete by the 50mm spacing for setting after determining, then obtain some row Leaf spring thickness h_x1Centrifugal pump, obtains first and second thickness h_x1With the 3rd thickness h_x2：

X distances	0	90	150	200	250	300	350	400	450	500	550	600	650	710	775	900
																		33	33	30.3	29.2	28.1	26.9	25.6	24.4	23	21.6	20.2	18.6	16.9	14.7	15	15

X distances	0	90	150	200	250	300	350	400	450	500	550	600	650	710	775	900
																		32	32	28.8	27.7	26.6	25.5	24.3	23.2	21.9	20.6	19.2	17.7	16.1	14	18	18

4. according to leaf spring thickness h_xThe expression formula of practical structures, the computational methods according to mechanics can obtain rigidity of plate spring First, two 110N/mm；Second 100.2N/mm.Global stiffness is 320.2N/mm

5. can determine that suspension offset frequency is according to rigidity of plate spring

Meet the design requirement of suspension, design terminates.It is respectively that two halves piece leaf spring is symmetrical, by grasswort 1, bag ear 2, the first mistake Cross the bending height h in region 3, the second transitional region 4 and transitional region₁Draw, First Transition region 3, the second transitional region 4 It is to be connected by straight line, there is fillet R90 in First Transition region 3, obtains three leaf springs of the different three monolithic leaf springs composition of rigidity Assembly structure, as shown in Figure 3.

The present invention expresses the practical structures of leaf spring using the form of piecewise function, can conveniently utilize different essences Degree is required to obtain the discretization data of parabola leaf spring, and quickly parabola plate is obtained in the case where only initial design parameters are known The concrete shape of spring；The rigidity of leaf spring is sought the piecewise function expression formula of practical structures using integration method, is eliminated to parabola The calculation error for simplifying and bringing, improve design computational accuracy.The present invention is provided for the design of few piece parabola leaf spring One kind is convenient, accurate computational methods, it is easy to operate, calculating process is fast, computational accuracy is high, output result facilitate Instructing manufacture with And the examination and test of products.

The embodiment above of the present invention, is merely illustrative, be not it is only, it is all within the scope of the present invention or it is equivalent this Change in the range of invention is surrounded by the present invention.

Claims (4)

1. a kind of method for designing of leaf spring made of steel plate, it is characterised in that：Its end of described leaf spring made of steel plate and root Portion is all thickness x cross sectional, and its end changes with root centre position section thickness according to parabola rule；According to parabola leaf spring The requirement of iso-stress, determines each position leaf spring thickness, and can press thickness by the principle at parabola according to iso-stress Exported according to different step-lengths, then according to plate spring shape is calculated under the conditions of iso-stress, calculate the rigidity of leaf spring, finally according to Whether offset frequency requirement inspection rigidity of plate spring meets design requirement, specifically includes following steps：

1) basic parameter is determined first, including bears load p, leaf spring width b, effective length L, straight segment length C, end thickness F, parabola rest position L₁；

2) leaf spring stress σ sizes are determined according to material and use condition, determines leaf spring thickness h_xChanging Pattern；

h_xChanging Pattern is：

$0.068{\mathrm{\σh}}_x^3-\frac{{\mathrm{bh}}_x^2\mathrm{\σ}}{6}+P_1(L-x)=0$

Wherein：X is that the distance away from centre bolt is put on leaf spring；

3) according to the leaf spring root thickness determined by experience and arrangement, the thickness one in the parabola thickness by calculating Cause, end thickness determines according in the first step, so leaf spring practical structures, plate can be determined according to x different spans Spring thickness h_xA series of Changing Patterns, leaf spring thickness h are obtained with the value difference of x_xChanging Pattern with x is：

$h_x=\left\{\begin{array}{cc}0.068{\mathrm{\&sigma;h}}_x^3-\frac{{\mathrm{bh}}_x^2\mathrm{\&sigma;}}{6}+P_{1}L=0& 0\&le;x\&le;C\\ 0.068{\mathrm{\&sigma;h}}_x^3-\frac{{\mathrm{bh}}_x^2\mathrm{\&sigma;}}{6}+P_1(L-x)=0& C<x<L1\\ F& L1\&le;x\&le;L\end{array}\right.$

According to leaf spring rolling accuracy in the required precision and actual production of design, a series of discretization of a determining deviation is taken to x Point, can obtain corresponding some strake spring thickness values h_xDiscretization point.By leaf spring thickness value h_xDiscretization point is from calculation procedure Output has just obtained the shape of the leaf spring for being actually needed rolling；

4) the leaf spring thickness h being calculated using previous step_x, cantilever beam deformation method is asked for integration method according in mechanics, calculate Leaf spring deflection, wherein coefficient are obtained according to the continuity hypothesis of fine strain of millet；

$\mathrm{\&omega;}=\&Integral;\&Integral;\left(\frac{P_1(L-x)}{{\mathrm{EI}}_x}dx\right)dx+Cx+D$

Wherein：

$I_x=\frac{{\mathrm{bh}}_x^2}{12}-0.034h_x^4=\left\{\begin{array}{c}\frac{1}{12b^{\frac{1}{2}}}{\left(\frac{6{\mathrm{LP}}_1}{\mathrm{\&sigma;}}\right)}^{\frac{3}{2}}-0.034{\left(\frac{6P_{1}L}{\mathrm{\&sigma;}b}\right)}^2,0\&le;x\&le;C\\ \frac{{\left(6P_1\right)}^{\frac{3}{2}}}{12b^{\frac{1}{2}}{\mathrm{\&sigma;}}^{\frac{3}{2}}}{(L-x)}^{\frac{3}{2}}-0.034{\left(\frac{6P_1(L-x)}{\mathrm{\&sigma;}b}\right)}^2,C<x<L1\\ \frac{{\mathrm{bF}}^3}{12}-0.034F^4,L1\&le;x\&le;L\end{array}\right.$

The rigidity of leaf spring can be calculated according to following formula：

$K_1=\frac{P_1}{w}$

5) requirement according to vehicle for suspension offset frequency, it is determined that under the conditions of selected iso-stress, whether rigidity meets the requirements；Offset frequency Computing formula calculate according to the following formula：

$f_1=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{K_1}{m_1}}.$

2. the method for designing of leaf spring made of steel plate according to claim 1, it is characterised in that：In the step (2) Leaf spring thickness change rule is that the practical structures of leaf spring are expressed using the form of piecewise function, can conveniently using different Required precision obtain the discretization data of parabola leaf spring.

3. the method for designing of leaf spring made of steel plate according to claim 1, it is characterised in that：In the step (3) The shape of leaf spring can be according to difference according to the constant spacing that the form of the discretization data point of constant spacing exports discretization point Required precision is selected.

4. the method for designing of leaf spring made of steel plate according to claim 1, it is characterised in that：Plate in the step (4) Spring Rigidity Calculation is that the rigidity of leaf spring is sought the piecewise function expression formula of practical structures using integration method, is eliminated to parabolical The calculation error for simplifying and bringing.