SU576526A1 - Method of detecting flaws in machine components - Google Patents

Description

one

The invention relates to the field of mechanical engineering and can be used in many industries in the field of vibro-acoustic control of the technical state of machines and mechanisms during their operation.

A known method for determining defects in rolling bearings, based on the principle of registering their vibration, consists in fixing the amplitude spectrum of the test floor, the hips, installing them into the product, creating an additional viral axial load, loading the bearings at this load, registering the vibrational spectrum of the assembled product and when harmonic components appear, they are with frequencies multiple to twice the oscillation frequency of rolling elements of bearings, judging by the presence of bearing defects 1.

However, the known method is difficult to dry, because of the need to pre-register the spectrum of the investigated yodishinika, install it in the product and create an additional axial load. This does not allow the method to be used directly in the production conditions of the operation of machines with their technical diagnostics and limits its scope. The known method can be applied only for detecting defects in rolling bearings and not

It is possible to judge the extent of their damage.

There is also known a method which, due to its technical dryness, is the most

close to the invention, based on the principle of recording the vibration of machine parts, which consists in recording the magnitude of the maximum peak value of the vibration signal and the shift of its frequency 2.

A feature of the known method is the creation of vibration in the investigated part with a predetermined resonant frequency. In this case, the frequency shift is set only at the moment when the predetermined

critical value and towards lower frequencies. By this feature, it is determined that the test piece has a defect.

However, the known method can be applied only for testing parts in the form of thin plates and only in laboratory conditions, since this requires a special excitation device. In the tested parts, oscillations with a given resonance frequency and the parts are placed under special conditions (vacuum, high temperature and etc.) In addition, the known method does not allow to assess the degree of wear of parts, since with its help it is possible to fix only the moment of destruction of the part, therefore

Claims (2)

It should not be used for vibro-acoustic diagnostics of the technical condition of machines. The purpose of the invention is to expand the range of parts and assess their degree of wear. For this, but the proposed method records the maximum peak value of the vibration signal during operation of the parts in the operating mechanism, determines the moment of metal appearance in the lubricant of the investigated parts, which measures the frequency of the maximum of the vibration signal, and remembers it, during the subsequent measurement time shifting the frequency of the maximum peak value of the vibration signal towards higher frequencies from the original value, and comparing this shift with the previously memorized value of Toty, judged on the defect and the degree of wear of machine parts. The drawing shows a plot of the frequency of the maximum peak value of a vibrosignal (ordinate axis) versus the concentration of metal inclusions in the lubricant of parts and the change in viscosity of the lubricant (abscissa axis). The method is carried out as follows. The vibration is fixed at one of its distribution points from the part being examined (for example, on the outer bearing race when inspecting the gearbox parts). The maximum peak value of the vibration signal, which appears at the natural frequency of parts, determines the changes made by external influences on the vibration signal, such as attenuation of the environment. The value of the resonant frequency of the part can be estimated by the formula where Sha is the resonant acceleration frequency; syo - natural frequency; b - constant attenuation. With an increase in the magnitude of the constant damping b, the resonant frequency of the acceleration of the vibration increases. Since the appearance of metallic inclusions in the lubricant of parts, increasing its viscosity, proportionally increases the magnitude of the constant damping b, the frequency of the maximum peak value of the vibration signal shifts towards higher frequencies. The magnitude of this shift characterizes the number of metallic inclusions in the lubricant of the investigated parts and, consequently, the degree of wear of the controlled parts. Taking into account these regularities, it determines the moment of occurrence of metallic inclusions in the lubricant of the investigated parts, in which the frequency of the maximum peak value of the vibration signal is measured and its value is memorized. Then, the shift of this frequency relative to the initial value is constantly measured as metallic inclusions appear in the lubrication of parts. The magnitude of the frequency shift of the maximum vibration signal is judged on the degree of wear of machine parts. In order to quantify the degree of wear of machine parts, a critical value of the frequency shift of the peak frequency of the maximum peak value of the vibration signal is preliminarily determined and a calibration chart is made for this type of parts and their operating conditions. Critical values of metal concentration in the lubricant and viscosity of this lubricant according to GOST are found. Further, using the calibration schedule directly under the operating conditions of the machines when conducting vibroacoustic diagnostics, the number of defects and the degree of wear of the machine parts are determined by comparing the current values of the frequency change with the calibration curve. Thus, using the regularity of the effect of metallic inclusions in the lubrication of parts on the frequency of the maximum peak value of their vibrosignal, the defects and the wall of wear of the parts are shifted towards a higher frequency. Claims The method of determining defects in machine parts, based on the principle of recording their vibration, is that they fix the maximum peak value of the vibration signal and its frequency shift, which is characterized by the fact that, in order to expand the nomenclature of parts and assess their wear, fisk the value of the maximum peak value of the vibrosignal during operation of parts in the operating mechanism, determine the time of occurrence of the metal in the lubricant of the investigated parts, which measure the frequency aksimuma vibration signal and storing it during a subsequent measurement time determined by the magnitude of the frequency shift of the maximum peak value of the vibration signal in the direction of higher frequencies from nervonachalnogo value and by comparing this shift with the value previously memorized frequency is judged on the defect and the degree of wear of machine parts. Sources of information taken into account in the examination 1. Copyright certificate № 360579, cl. G ORS 13/04, 1972. 2. Flexural Fatigue Machine for High Temperature Operation at Resonance in Vacuum, volume 37, number 3, p. 311-315, 1966. CJa / g ".) cr .. S / finocTm,