Method, system and equipment for measuring dynamic stress of small-size bevel gear

Abstract

The invention discloses a small-size bevel gear dynamic stress measurement method, system and device, and belongs to the technical field of stress tests.The small-size bevel gear dynamic stress measurement method comprises the steps that the geometric dimension similarity ratio of a bevel gear is determined; according to a dynamic similarity theory and a geometric dimension similarity ratio, determining a similarity ratio of each parameter of the bevel gear to obtain a bevel gear model; based on the bevel gear model, determining the pasting position of a strain gauge; and carrying out dynamic stress measurement on the bevel gear model. According to the method, the dynamic similarity theory is adopted, the geometrically similar bevel gear model is constructed, the dynamic similarity relation is verified through finite element calculation, and the result provides a theoretical basis for the dynamic characteristic test of the small-size and high-rotating-speed bevel gear.

Description

Technical Field

[0001] The present invention belongs to the technical field of stress testing, and in particular relates to a method, system and equipment for measuring dynamic stress of small-sized bevel gears. Background Art

[0002] Bevel gears are also commonly called bevel gears. Bevel gears are usually used in industrial transmission fields such as vehicles, ships, and aerospace. They have the characteristics of long life, light weight, low cost, strong load-bearing capacity, and vibration and noise reduction. As gear transmission develops towards high speed and heavy load, the vibration and noise problems of bevel gears are becoming more and more serious, and bevel gear failures caused by resonance are becoming more and more serious. Therefore, it is increasingly important to reasonably avoid resonance within the operating speed range of bevel gears or take corresponding vibration and noise reduction measures. The vibration design and analysis of bevel gears is the basis of bevel gear design, optimization and development, and it protects the high-precision transmission of bevel gears.

[0003] Bevel gears are often at risk of pitch resonance within the operating speed range, and gear vibration failures are becoming more and more serious. Measuring the dynamic stress of gears by attaching strain gauges is an effective way to determine whether the gears have failures caused by resonance. Although dynamic stress measurement technology has become increasingly mature, some bevel gears are small in size and cannot be directly measured by attaching strain gauges. How to measure the dynamic stress of such gears to evaluate their high-cycle fatigue resistance has not been solved. Summary of the invention

[0004] In view of the above problems, the present invention discloses a method for measuring dynamic stress of a small-sized bevel gear, comprising the following steps:

[0005] Determine the geometric similarity ratio of bevel gears;

[0006] According to the dynamic similarity theory and the geometric size similarity ratio, the similarity ratio of each parameter of the bevel gear is determined to obtain the bevel gear model;

[0007] Based on the bevel gear model, determine the patch position of the strain gauge;

[0008] Dynamic stress measurements on a bevel gear model.

[0009] Furthermore, the method of determining the similarity ratio of various parameters of the bevel gear according to the dynamic similarity theory and the geometric dimension similarity ratio to obtain the bevel gear model includes the following steps:

[0010] Determine similarity criteria based on equation analysis and dynamic similarity theory;

[0011] Based on the similarity criterion and the geometrical dimension similarity ratio, the similarity ratio of each parameter of the bevel gear is determined;

[0012] Based on the similarity ratio of each parameter, the bevel gear model is determined.

[0013] Furthermore, the similarity ratios of the various parameters include mass similarity ratio, damping similarity ratio, stiffness similarity ratio, force similarity ratio, displacement similarity ratio, time similarity ratio, density similarity ratio, elastic modulus similarity ratio, excitation frequency similarity ratio, natural frequency similarity ratio, velocity similarity ratio, acceleration similarity ratio, rotational speed similarity ratio and stress similarity ratio.

[0014] Furthermore, the similarity criterion is determined by the following formula:

[0015]

[0016] Among them, A C is the damping similarity ratio; A F A is the force similarity ratio; t is the time similarity ratio; A l A is the geometric size similarity ratio; ρ is the density similarity ratio; A E is the elastic modulus similarity ratio.

[0017] Furthermore, the geometric similarity ratio A l =λ;

[0018] Mass similarity ratio A M =λ 3 ;

[0019] Damping similarity ratio A C =λ 2 ;

[0020] Stiffness similarity ratio A K =λ;

[0021] Force similarity ratio A F =λ 2 ;

[0022] Displacement similarity ratio A X =λ;

[0023] Time similarity ratio A t =λ;

[0024] Density similarity ratio A ρ =1;

[0025] Elastic modulus similarity ratio A E =1;

[0026] Excitation frequency similarity ratio A f =1 / λ;

[0027] Natural frequency similarity ratio A ω =1 / λ;

[0028] Speed ​​similarity ratio A v =1;

[0029] Acceleration similarity ratio A a =1 / λ;

[0030] Speed ​​similarity ratio A Ω =1 / λ;

[0031] Stress similarity ratio A σ =1;

[0032] Among them, λ is the magnification of the bevel gear.

[0033] Furthermore, the patch position requirements of the strain gauge are as follows:

[0034] The ratio of the patch position coordinates of the bevel gear model strain gauge to the patch position coordinates of the original bevel gear strain gauge is a geometric size similarity ratio, and the strain gauge patch directions are consistent.

[0035] Furthermore, the patch position sensitivity of the strain gauge is determined by the following formula:

[0036]

[0037] Among them, (σ i ) cs is the stress in the patch direction; σ eqv is the equivalent stress; σ1 is the maximum principal stress; σ3 is the minimum principal stress.

[0038] The present invention also discloses a small-size bevel gear dynamic stress measurement system, comprising:

[0039] The geometrical similarity ratio unit is used to determine the geometrical similarity ratio of bevel gears;

[0040] The bevel gear model unit is used to determine the similarity ratio of various parameters of the bevel gear according to the dynamic similarity theory and the geometric size similarity ratio, and obtain the bevel gear model;

[0041] The patch position unit is used to determine the patch position of the strain gauge based on the bevel gear model;

[0042] Measuring unit for dynamic stress measurements on bevel gear models.

[0043] Furthermore, the bevel gear model unit is specifically used for:

[0044] Determine similarity criteria based on equation analysis and dynamic similarity theory;

[0045] Based on the similarity criterion and the geometrical dimension similarity ratio, the similarity ratio of each parameter of the bevel gear is determined;

[0046] Based on the similarity ratio of each parameter, the bevel gear model is determined.

[0047] The present invention also discloses an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for measuring dynamic stress of small-size bevel gears is implemented.

[0048] Compared with the prior art, the embodiments of the present invention have at least the following advantages: a method for measuring the dynamic stress of small-sized bevel gears is proposed, and since there is a gradient change in the dynamic stress distribution on the bevel gears, after the bevel gear model is enlarged, the stress gradient change on the same area is smaller than the stress gradient change of the original bevel gear, so the measured dynamic stress data is more accurate, and the dynamic stress data can be used for high-cycle fatigue life assessment of the bevel gears; a geometrically similar bevel gear model is constructed using a dynamic similarity method, and its dynamic similarity relationship is verified through finite element calculation. The results provide a theoretical basis for dynamic characteristic tests of small-sized, high-speed bevel gears.

[0049] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A flow chart showing a method for measuring dynamic stress of a small-sized bevel gear according to an embodiment of the present invention is shown;

[0052] Figure 2 A Campbell diagram showing a bevel gear according to an embodiment of the present invention;

[0053] Figure 3 A Campbell diagram of a bevel gear model according to an embodiment of the present invention is shown;

[0054] Figure 4 The dynamic stress cloud diagram of 7-node diameters according to an embodiment of the present invention is shown;

[0055] Figure 5 A schematic diagram of patch positions of 7 diameters according to an embodiment of the present invention is shown;

[0056] Figure 6 A schematic diagram of a small-size bevel gear dynamic stress measurement system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Figure 1 FIG. 1 is a flow chart showing a method for measuring dynamic stress of a small-sized bevel gear according to an embodiment of the present invention. Figure 1 As shown, a method for measuring dynamic stress of a small-sized bevel gear proposed by the present invention comprises the following steps:

[0059] Step 1: Determine the geometric magnification of the bevel gear, i.e. the geometric dimension similarity ratio A, based on the vibration characteristic analysis results of the bevel gear, the rotational speed of the drive equipment, the transmission relationship of the bevel gear pair, the requirements of the dynamic stress test patch and the dynamic similarity theory. l :

[0060] In order to measure the dynamic stress of the bevel gear and meet the patch requirements, the bevel gear needs to be enlarged. According to the dynamic similarity theory, the magnification of the bevel gear, that is, the geometric dimension similarity ratio A, is determined. l =λ, λ>1. The geometrical dimensions of the bevel gear model to be measured are λ times the geometrical dimensions of the original bevel gear.

[0061] According to the dynamic similarity theory, the gear that has a meshing relationship with the bevel gear in actual work is similarly enlarged. The similarity enlargement ratio is consistent with the bevel gear, and its geometric size similarity ratio is A l =λ, λ>1. Only the web and gear teeth are required to be similarly enlarged to simulate the meshing of the gear pair and the web load transmission. The gear shaft can adopt a universal design to facilitate installation and drive equipment rotation and power input.

[0062] The meshing relationship of the enlarged bevel gear pair is consistent with that of the original bevel gear pair, and they have the same transmission ratio. According to the dynamic similarity theory, the speed similarity ratio A Ω =1 / λ. The speed of the bevel gear model to be tested is 1 / λ times the speed of the original bevel gear. The bevel gear to be tested and the bevel gear model to be tested have the same speed similarity ratio. That is, the greater the model magnification, the smaller the required speed of the driving device. Therefore, the geometric dimension similarity ratio must also be determined based on the speed that the driving device can drive.

[0063] Step 2: According to vibration characteristic analysis, dynamic similarity theory, geometric dimension similarity ratio, material selection, etc., the similarity ratios of other parameters of the bevel gear are determined to obtain the bevel gear model;

[0064] The material of the enlarged bevel gear model to be tested is the same as that of the original bevel gear, so the similarity ratios of material density and elastic modulus are A ρ =1 and A E = 1. The mechanical properties parameters of the bevel gear model to be tested are consistent with the mechanical properties parameters of the original bevel gear material.

[0065] There is no requirement on the material of the magnified test bevel gear, and the same type of material with lower cost can be used.

[0066] According to the dynamic similarity theory, the natural frequency similarity ratio A ω =1 / λ. The natural frequency of the bevel gear model to be measured is 1 / λ times the natural frequency of the original bevel gear.

[0067] According to the dynamic similarity theory, the resonant speed similarity ratio is the gear rotation speed similarity ratio A. Ω =1 / λ. The resonant speed of the bevel gear model to be measured is 1 / λ times the resonant speed of the original bevel gear.

[0068] According to the dynamic similarity theory, the stress similarity ratio A σ = 1. The stress distribution of the bevel gear model to be tested is consistent with that of the original bevel gear, and the stress magnitudes at the corresponding positions are the same.

[0069] Dynamic similarity is a method of predicting the dynamic characteristics of a prototype through a similarity model. Dimensional analysis or equation analysis is usually used to determine the similarity criterion. Dimensional analysis is an expression of derived measurement units expressed by basic measurement units. This method examines the dimensions of each physical quantity in the process of studying similarity problems, and its theoretical basis is the theory of dimensional homogeneous equations. The equation analysis method is to use a consistent differential equation, integral equation or physical equation to solve the similarity criterion when the mathematical equation of the physical model is known. The present invention uses equation analysis to theoretically derive the similarity criterion, thereby obtaining the similarity relationship between various physical quantities.

[0070] The differential equation of motion of a multi-degree-of-freedom system under the action of external force F(t) is:

[0071]

[0072] Among them, M is mass; t is time; C is damping; K is stiffness; X is displacement; F is force.

[0073] Now use subscript n to represent the original bevel gear, subscript m to represent the bevel gear model, and the motion differential equations of the original bevel gear and the bevel gear model are:

[0074]

[0075] Now use AM , A C , A K , A F , A X , A t , A l , A ρ , A E , A f , A ω They represent mass similarity ratio, damping similarity ratio, stiffness similarity ratio, force similarity ratio, displacement similarity ratio, time similarity ratio, geometric size similarity ratio, density similarity ratio, elastic modulus similarity ratio, excitation frequency similarity ratio and natural frequency similarity ratio. v , A a , A Ω , A σ Respectively represent the velocity similarity ratio, acceleration similarity ratio, rotational speed similarity ratio and stress similarity ratio. Then:

[0076]

[0077] According to the relationship between various physical quantities:

[0078] M=ρV, then we have

[0079] A X =A l ;

[0080] F=KX=ES, then A F =A K A X =A E A S =A E A l 2 .

[0081] Where ρ is density; V is volume; E is elastic modulus; S is area; A S is the area similarity ratio.

[0082] Simplifying formula (4), we can get:

[0083]

[0084] According to formula (3) and formula (5), in order to make the models similar, the following similarity criteria can be obtained:

[0085]

[0086] Usually, the bevel gear model uses the same material as the original bevel gear, so there is A E =A ρ=1, in this paper, the geometric similarity ratio of bevel gear is set to A l =λ, we can get:

[0087] A l =λ,A t =λ, A c =λ 2 (7)

[0088] System speed similarity ratio A v Similarity ratio to acceleration A a The following relations are satisfied:

[0089] A v =1,

[0090] In addition, according to the relationship between stress and load, and the relationship between rotation speed and speed, it can be known that the stress similarity ratio A σ Similar to the speed ratio A Ω Satisfies the following relationship:

[0091] A σ =1, A Ω =1 / λ(9)

[0092] In summary, the similarity ratio of each physical quantity in the dynamic similarity design can be obtained, see Table 1, and the bevel gear model is obtained.

[0093] A geometrically similar bevel gear model was constructed using the dynamic similarity method, and its dynamic similarity relationship was verified through finite element calculation. The results provide a theoretical basis for dynamic characteristic tests of small-sized and high-speed bevel gears.

[0094] Thus, according to the structure designed according to the above similarity ratio, the inherent characteristics and response of the system should satisfy the similarity relationship given in Table 1.

[0095] Table 1 Parameter similarity ratio

[0096]

[0097] Among them, λ is the magnification of the bevel gear.

[0098] Step 3: Determine the patch position and sensitivity analysis of the strain gauge based on vibration characteristic analysis, dynamic similarity theory and bevel gear model;

[0099] According to the dynamic similarity theory, the ratio of the patch position coordinates of the strain gauge of the bevel gear model to be tested to the patch position coordinates of the original bevel gear strain gauge is the geometric size similarity ratio λ, and the strain gauge patch directions are consistent.

[0100] According to the dynamic similarity theory, the sensitivity of the dynamic stress test patch position of the bevel gear model to be tested is consistent with the sensitivity of the dynamic stress measurement patch position of the original bevel gear.

[0101] The strain gauge's patch position sensitivity is determined by the following formula:

[0102]

[0103] Among them, (σ i ) cs is the stress in the patch direction; σ eqv is the equivalent stress; σ1 is the maximum principal stress; σ3 is the minimum principal stress.

[0104] According to the dynamic similarity theory, the maximum dynamic stress converted from the actual measurement of the bevel gear model to be tested is the maximum dynamic stress of the original bevel gear.

[0105] Since the strain gauge is of a certain size, the stress gradient change on the same area of ​​the bevel gear model to be measured is smaller than the stress gradient change of the original bevel gear, so the measured dynamic stress data is more accurate.

[0106] Step 4: Measure the dynamic stress of the bevel gear model;

[0107] The dynamic stress measurement test is carried out by driving the transmission shaft driven by the driving device, which in turn drives the companion bevel gear to rotate, thereby driving the bevel gear model to be tested through meshing. A patch is placed on the bevel gear model to be tested, and the dynamic stress can be measured by connecting it to the dynamic stress test system. Then, based on the sensitivity of the patch position, the maximum dynamic stress is converted and the pitch-diameter order of the resonance is determined.

[0108] The maximum dynamic stress and the resonant pitch diameter order actually measured for the bevel gear model to be tested are the maximum dynamic stress and the resonant pitch diameter order of the original bevel gear.

[0109] The test results can be used for high cycle fatigue life assessment of bevel gears.

[0110] like Figure 6 As shown, based on the above-mentioned small-size bevel gear dynamic stress measurement method, this embodiment proposes a small-size bevel gear dynamic stress measurement system, including:

[0111] The geometrical similarity ratio unit is used to determine the geometrical similarity ratio of bevel gears;

[0112] The bevel gear model unit is used to determine the similarity ratio of various parameters of the bevel gear according to the dynamic similarity theory and the geometric size similarity ratio, and obtain the bevel gear model;

[0113] The patch position unit is used to determine the patch position of the strain gauge based on the bevel gear model;

[0114] Measuring unit for dynamic stress measurements on bevel gear models.

[0115] In some embodiments, the bevel gear model unit is specifically used for:

[0116] Determine similarity criteria based on equation analysis and dynamic similarity theory;

[0117] Based on the similarity criterion and the geometrical dimension similarity ratio, the similarity ratio of each parameter of the bevel gear is determined;

[0118] Based on the similarity ratio of each parameter, the bevel gear model is determined.

[0119] The present invention also proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for measuring dynamic stress of small-sized bevel gears when executing the computer program.

[0120] The present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for measuring dynamic stress of a small-sized bevel gear is implemented.

[0121] The reduction transmission bevel gear of a certain type of aircraft engine has the characteristics of small size and high speed. The vibration characteristic analysis results show that there is a risk of pitch-diameter resonance within the working speed range.

[0122] The prototype bevel gear was established, and the geometric dimensions of the bevel gear were enlarged by 2.0 times, that is, the 2.0 bevel gear model. The vibration characteristics analysis results of the prototype and the 2.0 bevel gear model are shown in Table 2. In addition, according to the similarity relationship in Table 1, the speed similarity ratio of the 2.0 bevel gear model is 0.5, and the Campbell diagrams of the two models are shown in Table 2. Figure 2 and Figure 3 ,It can be seen from the figure that the vibration order of the prototype bevel gear and the 2.0 bevel gear model pitch diameter type is the same, the frequency and resonance speed meet the similarity ratio, and the resonance speed within the working speed range is shown in Table 3.

[0123] Table 2 Gear vibration characteristics analysis results

[0124]

[0125] Table 3 Gear resonance speed

[0126]

[0127] From the analysis results of the vibration characteristics of the gears and the resonant speed, we can see that the similarity relationship is satisfied, that is, the modes of each order are similar. The gear frequencies and resonant speeds of the 2.0 bevel gear model are 0.5 times those of the prototype.

[0128] There is a risk of resonance in the working speed range of bevel gears. In engineering, the ability of bevel gears to resist high-cycle fatigue risks is often evaluated by testing and measuring their dynamic stress. However, due to the small structure of the prototype bevel gear, it is not convenient to measure the dynamic stress. The present invention uses the method of dynamic similarity theory to enlarge the geometric size of the bevel gear, and uses the similarity criterion to reflect the dynamic characteristics of the prototype by using the dynamic characteristics of the bevel gear model. The dynamic stress cloud diagram of the 7-pitch diameter in the working speed range of the prototype bevel gear and the bevel gear model of the present invention is shown in Figure 4 shown. Figure 4 (a) is the dynamic stress contour of the prototype bevel gear with a pitch diameter of 7; Figure 4 (b) is the dynamic stress contour diagram of the 7th pitch diameter of the bevel gear model.

[0129] like Figure 4 (a) Figure 4 As shown in (b), the dynamic stress cloud diagram of the pitch diameter of the prototype bevel gear and the 2.0 bevel gear model shows that their dynamic stress distribution is completely similar, and the sensitivity of each position is also consistent. According to the stress similarity ratio in Table 1, when conducting the dynamic stress measurement test, the dynamic stress value measured at the patch position of the bevel gear model is the dynamic stress at the corresponding position on the prototype bevel gear.

[0130] In addition, since there is a gradient change in the dynamic stress distribution on the bevel gear, after the model is enlarged, the stress gradient change on the same area is smaller than the stress gradient change of the prototype bevel gear, so the measured dynamic stress data is more accurate.

[0131] Figure 5 (a) is a schematic diagram of the location of the 7-pitch diameter patch on the prototype bevel gear. Figure 5 (b) is a schematic diagram of the 7-pitch diameter patch position of the bevel gear model. Figure 5 (a) and Figure 5 As shown in (b), the strain gauge patch directions of both are along the circumferential direction. The patch position sensitivity calculation results of the prototype bevel gear and the bevel gear model are shown in Table 4. The strain gauge patch ratio of the two is the geometric size similarity ratio, and the sensitivity of the two is consistent.

[0132] Table 4 Patch position sensitivity calculation results (taking 7-node diameter as an example)

[0133]

[0134] The present invention carries out dynamic similarity design and research on the small size of the bevel gear structure of a certain type of engine. From the finite element calculation results, it can be seen that the dynamic characteristics of the geometrically similar bevel gear model satisfy the corresponding similarity relationship, and the geometrically enlarged bevel gear model can eliminate the influence of stress gradient changes on dynamic stress measurement data.

[0135] The dynamic similarity design result of the invention provides a theoretical basis for the dynamic stress test of the bevel gear. In engineering, the dynamic similarity design can be used to accurately predict the dynamic characteristics of the prototype bevel gear, which has strong practicality and high broad spectrum.

[0136] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring dynamic stress of small-size bevel gears, characterized in that: The following steps are involved: Determine the geometric similarity ratio of bevel gears; According to the dynamic similarity theory and the geometric size similarity ratio, the similarity ratio of each parameter of the bevel gear is determined to obtain the bevel gear model; Based on the bevel gear model, determine the patch position of the strain gauge; Dynamic stress measurements on a bevel gear model.

2. The method for measuring dynamic stress of small-size bevel gears according to claim 1, characterized in that: Determining the similarity ratio of various parameters of the bevel gear according to the dynamic similarity theory and the geometric dimension similarity ratio to obtain the bevel gear model includes the following steps: Determine similarity criteria based on equation analysis and dynamic similarity theory; Based on the similarity criterion and the geometrical dimension similarity ratio, the similarity ratio of each parameter of the bevel gear is determined; Based on the similarity ratio of each parameter, the bevel gear model is determined.

3. The method for measuring dynamic stress of small-size bevel gears according to claim 1 or 2, characterized in that: The similarity ratios of the various parameters include mass similarity ratio, damping similarity ratio, stiffness similarity ratio, force similarity ratio, displacement similarity ratio, time similarity ratio, density similarity ratio, elastic modulus similarity ratio, excitation frequency similarity ratio, natural frequency similarity ratio, velocity similarity ratio, acceleration similarity ratio, rotational speed similarity ratio and stress similarity ratio.

4. The method for measuring dynamic stress of small-size bevel gears according to claim 2, characterized in that: The similarity criterion is determined by the following formula: Among them, A C is the damping similarity ratio; A F A is the force similarity ratio; t is the time similarity ratio; A l A is the geometric size similarity ratio; ρ is the density similarity ratio; A E is the elastic modulus similarity ratio.

5. The method for measuring dynamic stress of small-size bevel gears according to claim 3, characterized in that: The geometrical similarity ratio A l =λ; Mass similarity ratio A M =λ 3 ; Damping similarity ratio A C =λ 2 ; Stiffness similarity ratio A K =λ; Force similarity ratio A F =λ 2 ; Displacement similarity ratio A X =λ; Time similarity ratio A t =λ; Density similarity ratio A ρ =1; Elastic modulus similarity ratio A E =1; Excitation frequency similarity ratio A f =1 / λ; Natural frequency similarity ratio A ω =1 / λ; Speed ​​similarity ratio A v =1; Acceleration similarity ratio A a =1 / λ; Speed ​​similarity ratio A Ω =1 / λ; Stress similarity ratio A σ =1; Among them, λ is the magnification of the bevel gear.

6. The method for measuring dynamic stress of small-size bevel gears according to claim 1, characterized in that: The patch position requirements of the strain gauge are as follows: The ratio of the patch position coordinates of the bevel gear model strain gauge to the patch position coordinates of the original bevel gear strain gauge is a geometric size similarity ratio, and the strain gauge patch directions are consistent.

7. The method for measuring dynamic stress of small-size bevel gears according to claim 1, characterized in that: The patch position sensitivity of the strain gauge is determined by the following formula: Among them, (σ i ) cs is the stress in the patch direction; σ eqv is the equivalent stress; σ1 is the maximum principal stress; σ3 is the minimum principal stress.

8. A small-size bevel gear dynamic stress measurement system, characterized in that: include: The geometrical dimension similarity ratio unit is used to determine the geometrical dimension similarity ratio of the bevel gear; The bevel gear model unit is used to determine the similarity ratio of various parameters of the bevel gear according to the dynamic similarity theory and the geometric size similarity ratio, and obtain the bevel gear model; The patch position unit is used to determine the patch position of the strain gauge based on the bevel gear model; Measuring unit for dynamic stress measurements on bevel gear models.

9. The small-size bevel gear dynamic stress measurement system according to claim 8, characterized in that: The bevel gear model unit is specifically used for: Determine similarity criteria based on equation analysis and dynamic similarity theory; Based on the similarity criterion and the geometrical dimension similarity ratio, the similarity ratio of each parameter of the bevel gear is determined; Based on the similarity ratio of each parameter, the bevel gear model is determined.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for measuring dynamic stress of a small-size bevel gear according to any one of claims 1 to 7 is implemented.

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