Preparation method of high-precision Venturi valve characteristic nonlinear pressure spring and pressure spring

Abstract

The invention discloses a preparation method of a high-precision Venturi valve characteristic nonlinear pressure spring and the pressure spring, and the precise matching of the pressure spring performance and the Venturi valve nonlinear flow regulation characteristic is realized through the multi-step optimization design. The method comprises the following steps of establishing a venturi valve curve coordinate system, calculating an overflowing area, calculating resultant external force work, fitting a spring performance curve, determining a force value range, designing a spring gradual change process, performing heat treatment to remove stress, testing and correcting, ensuring that the spring performance meets the design requirement, and finishing final shaping. According to the method for calculating the stress change rule of the valve element of the Venturi valve under different valve front static pressures, the pressure and the spring force compensation required by the valve element damping structure of the Venturi valve are calculated by obtaining a theoretical stress curve, and through forward development, design and manufacturing, the valve element damping structure of the Venturi valve is obtained. And the air volume pressure independence and the air volume control precision of the Venturi valve are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of Venturi valves, and discloses a preparation method and a compression spring for a non-linear compression spring with high-precision Venturi valve characteristics. Background Art

[0002] A Venturi valve is a flow regulating device designed based on the principle of fluid dynamics, and is widely used in the fields of ventilation, gas transportation, and industrial fluid control. By changing the flow area inside the valve body, it uses the mutual relationship between flow velocity and pressure to achieve precise regulation of the flow rate. The performance of the Venturi valve directly determines the regulation accuracy and energy efficiency of the system, especially in occasions where high-precision flow control is required, such as clean room air conditioning systems, industrial burner gas supply, etc. However, due to the non-linear characteristics of fluid flow, the Venturi valve will exhibit significant complexity during actual operation, such as pressure loss, non-linear changes in the flow area, and dynamic responses under different working conditions.

[0003] In the design of traditional Venturi valves, the compression spring, as a key component, its performance directly affects the movement characteristics and regulation accuracy of the valve core. However, most traditional compression spring designs are based on the assumption of linear stiffness and cannot meet the regulation requirements of Venturi valves in complex non-linear fluid environments. This design method often leads to the following problems: First, the response of the valve core lags behind and cannot accurately match the rapid changes in the flow rate; Second, the compression spring works under high load conditions for a long time and is prone to plastic deformation, affecting its service life; Third, it is impossible to optimize the design according to the characteristic requirements under different working conditions, which limits the further development of Venturi valves in high-end application fields.

[0004] Currently, the compression springs used for pressure compensation in domestic Venturi valves are mainly manufactured by the reverse mapping method. For the use requirements of small pressure and high precision, the accuracy of the Venturi springs manufactured by the reverse and mapping methods deviates greatly from the theoretical curve, and the matching degree with the Venturi valve is not high, resulting in the accuracy of domestic brand Venturi valves being generally lower than that of international brands, which has a great impact on their performance. Summary of the Invention

[0005] To solve the above problems, the present invention provides a non-linear compression spring with high-precision Venturi valve characteristics and a preparation method thereof.

[0006] The technical solution provided by the present invention is as follows:

[0007] On the one hand, a preparation method for a non-linear compression spring with high-precision Venturi valve characteristics includes the following steps:

[0008] S1. Establish a coordinate system for the Venturi valve curve:

[0009] Define the axial direction of the valve body as the X-axis and the radial direction as the Y-axis, substitute the mapping data of the valve body into the coordinate system, and perform data processing to fit into a polynomial function in segments;

[0010] S2: Calculate and analyze the flow area according to the expression of the valve body curve:

[0011] The flow area of the Venturi valve is the minimum flow area from the current valve core to the valve body. Calculate the flow area of the valve core at different positions according to the geometric relationship and the valve body curve expression;

[0012] S3. Calculate the work done by the resultant force on the system:

[0013] ∑W W = p 2 S 2 Δl 2 - p 3 S 3 Δl 3

[0014] In the formula, ∑W W is the work done by the resultant force on the system, p is the fluid pressure on the cross-section, S is the cross-sectional area, and Δl is the displacement of the fluid within the unit time Δt;

[0015] S4. Fit the spring performance curve:

[0016] According to the work done by the resultant force on the system, calculate the dynamic pressure at the valve inlet before the valve and the flow pressure of the air flow at any flow area. When the limit is a fixed flow rate, the relationship between the spring force F (N) and the valve core position can be obtained at this flow rate, and the spring performance curve suitable for the Venturi valve can be fitted;

[0017] S5. Determine the force value range:

[0018] According to the Venturi flow rate range of different sizes, take the limit pressure at the maximum flow rate as the maximum load, and use this compensation force as the force value range of the Venturi characteristic compression spring;

[0019] S6. Determine the spring gradual change process:

[0020] According to the upper and lower limits of the force value, non-uniformly determine the control points. According to the force values and movement trajectories of the control points, determine the spring gradual change process, including the pitch and outer diameter. The characteristic is that along the air outlet to air inlet direction, the pitch gradually increases and the diameter gradually decreases;

[0021] S7. Perform stress relief treatment by heat treatment;

[0022] S8. Test and correct: Through the design of spring force value measurement, continuously adjust the correction coefficient to complete the final design and finalization.

[0023] In some embodiments, in step S1, the piecewise fitting into a polynomial function includes:

[0024] A first-degree polynomial, applicable to the part with relatively gentle changes and a linear trend;

[0025] A second-degree or third-degree polynomial, applicable to regions with more complex non-linear changes;

[0026] An exponential function. If the fitted curve shows obvious exponential decay or growth, or the pressure changes significantly with the flow rate, select the exponential function;

[0027] By segmenting the entire measurement data interval and using a suitable polynomial for fitting in each segment to ensure the fitting accuracy of each segment.

[0028] In some embodiments, in step S2, according to the continuity equation, the flow rate Q is equal in the same rectifier, that is, Q 2 = Q 3 , V = Δl / Δt, Δl 2 S 2 = Δl 3 S 3 = V, where is the average flow velocity of the fluid on the cross-section, V is the volume, and within the unit time Δt, the volume of the fluid passing through the two cross-sections is equal, and we can obtain:

[0029] ∑W W = (p 2 - p 3 )V

[0030] In some embodiments, in step S4, the method for fitting the spring performance curve suitable for the venturi valve is:

[0031] Venturi valves of the same model use the same spring, and the spring stiffness is a constant physical quantity. At different air volumes, the only difference lies in the initial compression position of the spring. When the spring forces are the same at different flow rates, it can be expressed as: F 1 (x) = F 2 (x + a);

[0032] In the formula, F 1 (x) is the relationship between the spring force and the spool position at the air volume Q1, F 2 (x) is the relationship between the spring force and the spool position at the air volume Q2, and a is the initial compression position of the spring at different air volumes;

[0033] Therefore, the relationship between the spring force and the spool position at different air volumes (Q1, Q2, Q3,..., Qn) is obtained:

[0034] F = F 1 (x) = F 2 (x + a 1 ) = F 3(x + a 2 ) =... = F n (x + a n-1 )

[0035] Thus, the spring performance curve suitable for the Venturi valve is fitted.

[0036] In some embodiments, in step S5, the method for determining the force value range is as follows:

[0037] The maximum working pressure of the Venturi characteristic compression spring is calculated as: Fmax(x) = S * ΔP + f(x);

[0038] where ΔP is the pressure difference before and after the valve cone, S is the cross-sectional area of the valve cone, and f(x) is the viscous resistance at different flow rates;

[0039] According to the viscous resistance Stokes formula f = 6πηrv, η is the viscosity coefficient of the fluid, and r is the radius of the valve cone of the Venturi valve;

[0040] According to the force value range, confirm the maximum stiffness, and screen the available spring materials and wire diameters:

[0041] P max = πd 3 / 8D τ0

[0042] where P max is the maximum load applied to the spring, τ ο is the shear stress, D is the average diameter of the spring coil, and d is the material diameter.

[0043] In some embodiments, in step S6, according to the minimum control force, first design the first pitch in the way of equal pitch and equal diameter with smooth transition. The pitch calculation method is mainly:

[0044]

[0045] x i0 is the compression displacement of each turn, k 1 is the target stiffness of the non-linear spring, Δ 0 is the working compression amount, N 0 where x i0 is the compression displacement of each turn, k is the target stiffness of the non-linear spring, δ 0 is the working compression amount, N is the number of turns corresponding to the working compression amount, N is the total number of turns, and i is the number of turns;

[0046] The calculation method of the diameter is:

[0047] D = πd 3 / 8P max το

[0048] Among them, P max represents the maximum load applied to the spring, τ ο represents the shear stress, D represents the mean diameter of the spring coil, and d represents the material diameter.

[0049] On the other hand, a high-precision venturi valve with non-linear characteristics of the compression spring includes a compression spring body. Along the direction from the air outlet to the air inlet of the venturi valve, the pitch gradually increases and the diameter gradually decreases.

[0050] In some embodiments, the maximum stiffness of the compression spring is 0.938 N / mm, and the diameter range is 20 - 50 mm.

[0051] In summary, the beneficial effects of the present invention are as follows:

[0052] (1) The present invention provides a calculation method for the law of force change of the valve core of a venturi valve and its valve core under different static pressures before the valve. By obtaining the theoretical force curve, the compression and spring force compensation required for the damping structure of the venturi valve core are calculated. Through positive development design and production, the air volume pressure independence and air volume control accuracy of the venturi valve are improved.

[0053] (2) For the final spring of the present invention, the adopted design and manufacturing include a combination of variable pitch and variable diameter, which brings a more delicate and accurate elastic force performance compared with the traditional single variable pitch and single variable diameter methods.

[0054] (3) By fitting the performance curve of the compression spring, the present invention adjusts the stiffness of the spring to be consistent with the curve characteristics of the valve body, which can significantly improve the response accuracy of the valve core to different flow rate changes, especially under complex working conditions, ensuring the accuracy of flow rate adjustment. Description of the Drawings

[0055] Figure 1 is the curve coordinate system of the venturi valve;

[0056] Figure 2 is the schematic diagram of the present over-flow area;

[0057] Figure 3 is the curve graph of the compression spring test and correction;

[0058] Figure 4 is the schematic diagram of the compression spring structure of the present invention;

[0059] Figure 5 is the schematic diagram of the compression spring installed in the venturi valve structure. Detailed Embodiments

[0060] To deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not limit the protection scope of the present invention.

[0061] The present invention provides a method for preparing a high-precision non-linear compression spring for the characteristics of a Venturi valve. The specific steps are as follows:

[0062] First, please refer to Figure 1 , establish a curvilinear coordinate system for the Venturi valve, define the axial direction of the valve body as the x-axis and the radial direction as the Y-axis. Adjust the surveyed coordinate system to the coordinate system shown in the above figure, and perform data processing on the surveyed data. In order to better reflect the change rate of the curve, it can be piecewise fitted into a polynomial function:

[0063] Fitting of the gentle region: For the part where the fluid velocity or pressure changes linearly, a first-degree polynomial fitting is used.

[0064] Fitting of the complex non-linear region: For the region where the fluid parameters change significantly, a second-degree or third-degree polynomial fitting is used to improve the fitting accuracy.

[0065] Fitting of the exponential change region: When the curve shows an obvious exponential growth or decay trend, an exponential function is selected for fitting.

[0066] By segmenting the entire measurement data interval and using a suitable polynomial for fitting in each segment, the fitting accuracy of each segment is ensured.

[0067] Specific fitting method:

[0068] 1. Data preprocessing: In order to ensure the fitting accuracy, the following processing needs to be performed on the collected data:

[0069] (1) Denoising processing: Abnormal points or noise data in the measurement process are removed, and smoothing filtering (such as Gaussian filtering) can be used for processing.

[0070] (2) Normalization: Normalize the data to a standard range (such as 0 to 1) to reduce the influence of data magnitude differences on fitting:

[0071]

[0072] (3) Segment analysis: According to the trend of data change, the curve is divided into multiple regions. The basis for segmentation can include the inflection point of the curve, the change of curvature, and the significant change points of flow rate and pressure difference.

[0073] 2. According to the characteristics of the curve data, select a suitable fitting function for each segment:

[0074] First-degree polynomial fitting model:

[0075] y = a1 x + b;

[0076] Quadratic polynomial fitting model:

[0077] y = a 2 x 2 + b 2 x + c;

[0078] Cubic polynomial fitting model:

[0079] y = a 3 x 3 + b 3 x 3 + c 3 x + d;

[0080] Exponential function fitting model:

[0081] y = a·e bx + c;

[0082] 3. Fitting calculation process:

[0083] 1. Determine the segmented region: Find the segmentation points x 1 , x 2 …x n ;

[0084] 2. In each segment, calculate the fitting coefficients a, b, c by the least squares method;

[0085] Error function:

[0086] Take the derivative of E and set it to 0 to solve for the coefficients a, b, c.

[0087] Since the Venturi valve has significant pressure independence, which means that in different pressure environments, the Venturi valve can maintain stable air volume control accuracy. To ensure a constant air volume flowing through the Venturi valve at different pressures, when the pressure difference changes, the valve core will automatically adjust to a suitable position to ensure that the flow area has a certain correlation with the pressure, thereby ensuring a constant air volume.

[0088] Therefore, the flow area can be calculated and analyzed according to the expression of the valve body curve.

[0089] Please refer to Figure 2 The flow area of the Venturi valve is the minimum flow area from the current valve core to the valve body. According to the geometric relationship and the expression of the valve body curve, the flow area at different positions of the valve core can be calculated.

[0090] According to the law of conservation of kinetic energy, that is, the total work done by the resultant force on the system is: ∑W W = p 2 S 2 Δl2 -p 3 S 3 Δl 3

[0091] Wherein, ∑W W is the work done by the resultant external force on the system, p is the pressure of the fluid on the cross-section, S is the cross-sectional area, and Δl is the displacement of the fluid within the unit time Δt.

[0092] According to the continuity equation, the flow rate Q is equal in the same streamline, that is, Q 2 = Q 3 、 V = Δl / Δt, Δl 2 S 2 = Δl 3 S 3 = V, where is the average flow velocity of the fluid on the cross-section, V is the volume, and within the unit time Δt, the volumes of the fluid passing through the two cross-sections are equal, and we can obtain:

[0093] ∑W W = (p 2 - p 3 )V.

[0094] Furthermore, the dynamic pressure at the valve inlet before and the flow pressure of the air flow at any passing area can be calculated. When restricted to a fixed flow rate, the relationship between the spring force F (N) and the spool position at this flow rate can be obtained:

[0095]

[0096] Since Venturi valves of the same model use the same spring, the spring stiffness is a constant physical quantity. At different air volumes, the difference lies only in the initial compression position of the spring. When the spring forces are the same at different flow rates, it can be expressed as: F 1 (x) = F 2 (x + a);

[0097] Wherein, F 1 (x) is the relational expression between the spring force and the spool position at the air volume Q1, F 2 (x) is the relational expression between the spring force and the spool position at the air volume Q2, and a is the initial compression position of the spring at different air volumes;

[0098] Therefore, the relational expressions between the spring force and the spool position at different air volumes (Q1, Q2, Q3,..., Qn) are obtained:

[0099] F = F 1 (x) = F 2 (x + a 1 ) = F 3 (x + a2 ) =... = F n (x + a n-1 )

[0100] Thus, a spring performance curve suitable for the Venturi valve is fitted.

[0101] According to the Venturi flow rate range of different sizes, the ultimate pressure at the maximum flow rate is taken as the maximum load. The maximum load is the maximum compensation for its non-linear elastic force, and based on this compensation force, the force value range of the Venturi characteristic compression spring is determined.

[0102] Usually, the maximum working pressure of the Venturi valve is 750 Pa. Then, the maximum working pressure of the Venturi characteristic compression spring is: Fmax(x) = S * ΔP + f(x);

[0103] Where, ΔP is the pressure difference before and after the valve cone, S is the cross-sectional area of the valve cone, and f(x) is the viscous resistance at different flow rates;

[0104] According to the Stokes formula of viscous resistance f = 6πηrv, η is the viscosity coefficient of the fluid, and r is the radius of the valve cone of the Venturi valve;

[0105] According to the force value range, confirm the maximum stiffness, and screen the available spring materials and wire diameters:

[0106] P max = πd 3 / 8D τ0

[0107] Where, P max is the maximum load applied to the spring, τ ο is the shear stress, D is the average diameter of the spring coil, and d is the material diameter.

[0108] Furthermore, according to the upper and lower limits of the force value, the control points are determined non-uniformly, from small to large. According to the force values and movement trajectories of the control points, from small to large, the spring gradual change process is determined, mainly including the pitch and outer diameter.

[0109] The main features include that the pitch gradually increases and the diameter gradually decreases, and in this way, a more smooth non-linear mechanical performance with an exponential characteristic of transition is obtained;

[0110] According to the minimum control force, first design the first pitch in a smooth transition manner with equal pitch and equal diameter. The pitch calculation method is mainly:

[0111]

[0112] x i0 is the compression displacement of each coil, k 1 is the target stiffness of the non-linear spring, Δ 0 is the working compression amount, N0 where x i0 is the compression displacement of each coil, k is the target stiffness of the non - linear spring, δ 0 is the working compression amount, N is the number of coils corresponding to the working compression amount, N is the total number of coils, and i is the number of coils;

[0113] The calculation method of the diameter is:

[0114] D = πd 3 / 8P max το

[0115] where P max represents the maximum load applied to the spring, τ ο represents the shear stress, D represents the mean diameter of the spring coil, and d represents the material diameter. And so on, respectively, from the control force value and the compression displacement amount, in ascending order, the pitch and diameter of the spring are designed in turn.

[0116] Step S7, heat treatment is carried out to remove stress to ensure the elastic stability of the spring during long - term operation. The specific process parameters include:

[0117] Heat treatment temperature: 350 - 450 °C;

[0118] Insulation time: 1 - 2 hours;

[0119] Cooling method: slow cooling.

[0120] Through heat treatment, the internal stress of the spring can be effectively reduced and its durability can be improved.

[0121] S8, testing and correction: By designing the spring force value measurement and continuously adjusting the correction coefficient, the final design is finalized. Please refer to the test and correction curve graph Figure 3 .

[0122] This application also provides a compression spring prepared by the above method. Please refer to Figure 4 , Figure 5 , which includes a compression spring body. Along the direction from the air outlet to the air inlet of the Venturi valve, the pitch of the compression spring body gradually increases and the diameter gradually decreases.

[0123] When the maximum stiffness of the compression spring is 0.938 N / mm and the diameter range is 20 - 50 mm, it can ensure that the spring meets the material stress limit while providing the required stiffness, thus ensuring the accuracy of the Venturi valve.

[0124] The flow - through antibody microsphere packaging structure of this application can not only effectively fix the antibody microspheres and prevent their displacement, but also improve the storage safety and reliability through diversified limiting designs and monitoring means.

[0125] In summary, the present invention provides a calculation method for the variation law of the force on the spool of a Venturi valve and its spool under different static pressures before the valve. By obtaining the theoretical force curve, the pressing force and spring force compensation required for the damping structure of the Venturi valve spool are calculated. Through positive development design and production, the air volume-pressure independence and air volume control accuracy of the Venturi valve are improved.

[0126] It should be noted that in the drawings or the text of the specification, the implementation manners that are not depicted or described are all forms known to those of ordinary skill in the art and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or manners mentioned in the embodiments.

[0127] It should also be noted that this document may provide examples of parameters including specific values, but these parameters do not necessarily have to be exactly equal to the corresponding values, but may be approximated to the corresponding values within an acceptable error tolerance or design constraint. The directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., are only references to the directions in the drawings and are not used to limit the protection scope of this application.

[0128] The above description shows and describes the preferred embodiments of the present invention. As mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the inventive concept described herein through the above teachings or the technology or knowledge in the relevant field. And the changes and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should all be within the protection scope of the appended claims of the present invention.

Claims

1. A method for preparing a high-precision nonlinear compression spring for a Venturi valve, characterized in that: The following steps are involved: S1. Establish the Venturi valve curve coordinate system: The axial direction of the valve body is defined as the X-axis, and the radial direction is defined as the Y-axis. The surveying and mapping data of the valve body is substituted into the coordinate system, and the data is processed and piecewise fitted into a polynomial function. S2: Calculate and analyze the flow area according to the expression of the valve body curve: The flow area of ​​the Venturi valve is the minimum flow area from the current valve core to the valve body. The flow area of ​​the valve core at different positions is calculated based on the geometric relationship and the valve body curve expression. S3. Calculate the work done by the resultant external force on the system: ∑W W =p2S2Δl2-p3S3Δl3 In the formula, ∑W W is the work done by the resultant external force on the system, p is the pressure of the fluid on the cross section, S is the cross-sectional area, and Δl is the displacement of the fluid per unit time Δt; S4. Fitting spring performance curve: According to the work done by the combined external force on the system, the dynamic pressure at the inlet of the valve and the flow pressure of the outflow of any excess area are calculated. When the flow rate is limited to a fixed value, the relationship between the spring force F (N) and the valve core position under the flow rate can be obtained, and the spring performance curve suitable for the Venturi valve can be fitted. S5. Determine the force range: According to the flow range of Venturi of different sizes, the limit pressure at the maximum flow is taken as the maximum load, and the compensation force is used as the force range of the Venturi characteristic compression spring; S6. Determine the spring gradient process: According to the upper and lower limits of the force value, the control points are determined in a non-uniform distribution. According to the force value and motion trajectory of the control point, the gradual change process of the spring, including the pitch and outer diameter, is determined. The characteristic is that the pitch gradually increases and the diameter gradually decreases along the direction from the air outlet to the air inlet; S7, heat treatment for stress relief; S8. Test and correction: By measuring the design spring force value and continuously adjusting the correction coefficient, the final design is finalized.

2. The method for preparing a high-precision Venturi valve characteristic nonlinear compression spring according to claim 1, characterized in that: In step S1, piecewise fitting into a polynomial function includes: First-order polynomial, suitable for parts with relatively gentle changes and linear trends; Quadratic or cubic polynomials are suitable for areas with more complex nonlinear changes; Exponential function: If the fitted curve shows obvious exponential decay or growth, or the pressure changes greatly with flow rate, select the exponential function; The entire measurement data interval is divided into segments, and each segment is fitted using a suitable polynomial to ensure the fitting accuracy of each segment.

3. The method for preparing a high-precision Venturi valve characteristic nonlinear compression spring according to claim 1, characterized in that: In step S2, according to the continuity equation, the flow rate Q is equal in the same rectification, that is, Q2 = Q3, V=Δl / Δt, Δl2S2=Δl3S3=V, where is the average flow velocity of the fluid on the cross section, V is the volume, and within the unit time Δt, the volume of the fluid passing through the two cross sections is equal, so we can get: ∑W W = (p2-p3)V.

4. The method for preparing a high-precision Venturi valve characteristic nonlinear compression spring according to claim 3, characterized in that: In step S4, the method for fitting a spring performance curve suitable for the Venturi valve is: The same model of Venturi valve uses the same spring, and the spring stiffness is a constant physical quantity. Under different air volumes, the only difference is the initial compression position of the spring. Under different flow rates, when the spring force is the same, it can be expressed as: F1(x) = F2(x+a); In the formula, F1(x) is the relationship between the spring force and the valve core position under the air volume Q1, F2(x) is the relationship between the spring force and the valve core position under the air volume Q2, and a is the initial compression position of the spring at different air volumes; Therefore, the relationship between the spring force and the valve core position under different air volumes (Q1, Q2, Q3, ..., Qn) is obtained: F=F1(x)=F2(x+a1)=F3(x+a2)=...=F n (x+a n-1 ) Thus, a spring performance curve suitable for the Venturi valve is fitted.

5. The method for preparing a high-precision Venturi valve characteristic nonlinear compression spring according to claim 4, characterized in that: In step S5, the method for determining the force value range is: The maximum working pressure of the Venturi characteristic compression spring is calculated as: Fmax(x)=S*ΔP+f(x); Among them, ΔP is the pressure difference before and after the valve cone, S is the cross-sectional area of ​​the valve cone, and f(x) is the viscous resistance at different flow rates; According to the Stokes formula of viscous resistance, f = 6ππηv, η is the viscosity coefficient of the fluid, and r is the radius of the cone of the Venturi valve; According to the force range, confirm the maximum stiffness and select the material and wire diameter of the available springs: P max =πd 3 / 8D τ0 Among them, P max is the maximum load applied to the spring, τ ο is the shear stress, D is the average diameter of the spring coil, and d is the material diameter.

6. The method for preparing a high-precision Venturi valve characteristic nonlinear compression spring according to claim 5, characterized in that: In step S6, according to the minimum control force, the first pitch is first designed by adopting a smooth transition equal pitch and equal diameter method, and the pitch calculation method is mainly as follows: x i0 is the compression displacement of each circle, k1 is the target stiffness of the nonlinear spring, Δ0 is the working compression, N0 is, where x i0 is the compression and displacement of each circle, k is the target stiffness of the nonlinear spring, δ0 is the working compression, N is the number of circles corresponding to the working compression, N is the total number of circles, and i is the number of circles; The diameter is calculated as: <h2 style=";text-align:left;direction:ltr">D = πd<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> / 8P<h2 style=";text-align:left;direction:ltr"> max <h2 style=";text-align:left;direction:ltr"> το Among them, P max represents the maximum load applied to the spring, τ ο represents shear stress, D represents the average diameter of the spring coil, and d represents the material diameter.

7. A high-precision Venturi valve characteristic nonlinear compression spring, prepared by the high-precision Venturi valve characteristic nonlinear compression spring preparation method according to claims 1-6, comprising a compression spring body, characterized in that: The pitch of the compression spring body gradually increases and the diameter gradually decreases along the direction from the air outlet to the air inlet of the Venturi valve.

8. The high-precision Venturi valve characteristic nonlinear compression spring according to claim 7, characterized in that: The maximum stiffness of the compression spring is 0.938 N / mm, and the diameter range is 20-50 mm.

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