RU2430347C1 - Diagnostics procedure for disturbing forces of mechanism unit - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: according to procedure for diagnostics of disturbing forces of mechanism unit diagnostics is performed by values of amplitudes of accelerations of harmonic of resolution of Fourier for function of disturbing forces of unit, which are considered as values of one order (equal) in comparison with rapidly diminishing amplitudes (bias and velocity) with growth of number of harmonics and are accepted as results of measurement of one value at k of its measurements. There are determined amplitudes A_i of accelerations of harmonics i(1, 2, …, n) and their average value in all range of measurements

for frequency of rotation or disturbance of unit f₀ and load N₀. By indicator A_j>A_aver,n harmonic j(., 2, …,5, …,k) is chosen from all harmonics i(1, 2,…, n), for example, (A_j=A₂, A₅,…A_k) and there is determined diagnostics parameter

Quantitative value of reference of diagnostics A_aver=A_{aver k}±t is determined by rules of evaluation of average value A_{aver k}=A_aver for sufficiently large k(5…15), where t is coefficient of confidence probability, σA_{aver k} is average square deviation of average value.

EFFECT: upgraded accuracy of diagnostics of disturbing forces of mechanism unit.

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Description

The invention relates to technical diagnostics and allows you to diagnose the disturbing forces of the node, for example, the kinematic node of the mechanism during its operation (the shaft on the supports, loaded with disturbing forces transmitting power at its rotational speed).

There is a method of evaluating the technical condition of the mechanism [1], where the goal is achieved by the fact that they realize the vibration overloads, determine their spectral characteristics, enter the threshold level in the form of the mathematical expectation of the amplitudes of the harmonic components of the vibration overloads, determine the mathematical expectation M _{0 of the} amplitudes of the harmonic components of the vibration overloads that exceed the threshold the level and quantity K _{0 of} harmonic components whose amplitudes do not exceed the threshold level, and the technical state is limit by a complex change in the values of M ₀ and K ₀ .

The known method does not allow to obtain high accuracy in assessing the technical condition of the node, since it does not provide a quantitative determination of the values of the state standard, but only qualitative (by a complex change in M ₀ and K ₀ ).

In the proposed method, improving accuracy is achieved by two fundamental provisions: 1 - finding the reference values of the diagnostic parameter and conducting diagnostics at the selected speed and load of the node (s) of the mechanism in the working range of its operation, 2 - determining the numerical value and the boundaries of the standard state of the node using the properties amplitudes of accelerations of harmonics of the Fourier expansion of the function of the disturbing forces of the node (equality of the amplitudes of all harmonics of the frequency of its rotation).

The purpose of the invention is to increase the accuracy and efficiency of diagnosis by creating a method for obtaining a quantitative assessment of the disturbing forces of a node or all of its nodes at the same time.

на частоте вращения или возмущения узла f₀ и нагрузке N₀, по признаку A_j>А_ср.n выбирают из всех гармоник i(1, 2, …, n) гармоники j(., 2, …, 5, …, k), например (A_j=A₂, A₅, …, A_k), и определяют диагностический параметр

, а количественное значение эталона диагностики А_ср=A_cp.k±tσ_Acp.k определяют по правилам оценки среднего значения A_cp.k=А_ср для достаточно больших k(5…15), где t - коэффициент доверительной вероятности, σ_Acp.k - среднее квадратичное отклонение среднего значения.This goal is achieved due to the fact that the diagnosis is carried out by the values of the amplitudes of the accelerations of harmonics of the Fourier decomposition for the function of the disturbing forces of the node, which are considered as values of the same order (equal) in comparison with amplitudes rapidly decreasing with increasing number of harmonics (displacement and velocity) and take them as the results of measuring one quantity at k measurements, determine the amplitudes A _{i of} harmonics accelerations i (1, 2, ..., n) and their average value over the entire measurement range

at the speed of rotation or disturbance of the node f ₀ and load N ₀ , according to the sign A _j > A _cf.n , harmonics j (., 2, ..., 5, ..., k are selected from all harmonics i (1, 2, ..., n) ), for example (A _j = A ₂ , A ₅ , ..., A _k ), and determine the diagnostic parameter

, and the quantitative value of the diagnostic standard A _cf = A _cp.k ± tσ _Acp.k is determined by the rules for estimating the average value A _cp.k = A _cf for sufficiently large k (5 ... 15), where t is the confidence coefficient, σ _{Acp .k} is the standard deviation of the mean.

меньше [2], чем сами случайные величины.A significant increase in diagnostic accuracy occurs due to the fact that it is performed according to the average values of random variables A _i and A _j , and their average value changes to

less [2] than the random variables themselves.

The drawing shows a diagram of the implementation of this method for diagnosing a node disturbing forces of the mechanism. The signal from the vibration sensor 1, installed in an informative place of the mechanism on its supports or body, enters block 2 (ACS) - an automatic signal analysis control system.

путем сравнения его значения с эталоннымThe ACS selects from the spectrum of the sensor signal (the spectrum of the disturbing forces of the node) at load N _{0 the} frequency of the disturbance (rotation) of the node f ₀ and its harmonics A _i and A _j , determines the amplitude of vibration acceleration of harmonics A _i and A _j and controls the diagnostic parameter

by comparing its value with the reference

And _cp = A _cp.k ± tσ _Acp.k.

In case of exceeding the reference values of the parameter A _{cf, the} ACS gives a command to the actuator and to the visual control devices of the aircraft (test bench) to automatically or manually change the operating modes or terminate the operation of the mechanism.

Information sources

1. Shalaev F.N. Copyright certificate No. 672532, 1979. "Method for assessing the technical condition of the mechanism." Application No. 2517067. Priority of the invention on 8.8.1977. Registered in the State register of inventions of the USSR on March 15, 1979.

2. Birger I.A., Shorr B.F., Iosilevich G.B. Strength calculation of machine parts. Directory. M .: Engineering, 1979

Claims (1)

A method for diagnosing the disturbing forces of the mechanism node, which consists in the fact that the diagnostics are carried out by the values of the amplitudes of the accelerations of the harmonics of the Fourier decomposition for the function of the disturbing forces of the node, which are considered as values of the same order (equal) in comparison with the amplitudes (decreasing and speed ) and take them as the results of measuring one quantity at k measurements, determine the amplitudes A _i , accelerations of harmonics i (1, 2, ..., n) and their average value in the entire measurement range

at the speed of rotation or disturbance of the node ƒ ₀ and load N ₀ , according to the sign A _j > A _cp.n, choose from all harmonics i (1, 2, ..., n) the harmonics j (., 2, ..., 5, ..., k ), for example, (A _j = A ₂ , A ₅ , ..., A _k ) and determine the diagnostic parameter

and the quantitative value of the diagnostic standard A _cp = A _cp.k ± tσ _Acp.k is determined by the rules for evaluating the average value of A _cp.k = A _cp for sufficiently large k (5 ... 15), where t is the confidence coefficient, σ _{Asr. k} is the standard deviation of the mean.