LT5217B - A diagnostics method of drive belt - Google Patents

Abstract

The invention relates to belt drive flexible elements (belts) diagnostic field. The objective of this invention is to increase the reliability, efficiency and convenience of belt drive diagnostic. The recent or repaired belt drive is subjected to identifying fundamental and multiple excitation frequencies and dependence nomograms of belt drive excitation frequencies and belt longitudinal velocity were build. After measuring the vibrations of belt drive bearing housing and after performing analysis of signal spectrum, the recorded values of informative spectral components is not less than 0.3*fd(1), here fd(1) - is the natural frequency of the belt transverse vibrations, calculated according to the belt drive parameters and this data is assumed to be base data. During exploitation while periodically measuring the vibrations of the bearing housing, the values of the informative spectral components are being compared with base data and according to it the belt tension force and its state is determined.

Description

FIELD OF THE INVENTION The present invention relates to a field of methods for controlling the condition of in-service belt transmissions, free transmission operating mode and constant inter-axial distance, of flat, round, ratchet belts and transmission belt assemblies.

A known method of controlling the transfer belts on which the device for Russian Federation patent no. RU2115906; G01M13 / 02, 17/00; 1998] to assess the quality of newly manufactured belts and can accurately measure belt parameters that determine its durability, durability, energy dissipation, and cross-sectional dimensional stability. The method is based on parameter collection for estimation of the mode of forced oscillation, amplitude and frequency of lower pulley vibrations. In this method, the transmission is excited at a resonant frequency and measures the amplitude and frequency of the lower pulley vibrations, then determines the condition of the belt based on these parameters.

This method and the device based on it are ineffective, because in order to check the condition of the belt this device would require special stopping of the transmission, dismantling it and only after testing the belt itself on the test bench.

A known method of controlling the transfer belts on which the device is based is designed to [ U.S. Pat. 5,992,920; G01L1 / 26; 1999] to automatically measure the initial tension of the belt transfer belt during the assembly process of machinery such as washing machines or similar equipment. The method consists of deflecting the belt branch, measuring this deflection and determining the belt tension force. This method moves the deformation device to the position where the strap is deformed, then measures the pressure acting device and the distance the device has been displaced as the belt is deformed; using the measured pressure and displacement, determine whether the belt tension force is within the appropriate range.

This method and the device based on it are not suitable for controlling the belt tension force during operation, since the control of this parameter requires the transmission to be braked, allowing the belt branches to be loaded with static load. Therefore, this method has the disadvantage of inefficiency.

The object of the present invention is to provide a method of diagnosing belt gears, which would increase the reliability, efficiency and convenience of gears diagnostics, and which would be able to determine the condition of the belt during operation without stopping or disassembling the mechanism.

This goal is achieved by using this technique. consisting of the determination of the tension force of the belt branch and the evaluation of the condition of the belt, identifies the basic and repetitive excitation frequencies of the new or post-repair belt transmission. Having identified the belt transfer excitation frequencies, they form nomograms of the relationship between the belt transfer excitation frequencies and the belt branch transverse oscillation frequency, and the linear velocity v of the belt. It then measures the vibration of the belt transmission bearing seat and performs a spectral analysis of the signal and records the values of the informative components of the resulting spectrum at no lower than the first eigenvalue of the belt transverse oscillations calculated from the transmission parameters. Later, during operation, it periodically measures the bearing vibration, compares the values of the informative components of the obtained spectrum with the base data and determines the magnitude and condition of the belt tension force.

Example of a method application

1. For the purpose of identification, measure the distance between the drive axle a and the drive shaft of a new or post-repair transmission and their respective pulleys and obtain, for the particular transmission: a = 380 mm; <= 90 mm; d = 95 mm.

2. Calculates the length of the belt branch not in contact with the pulleys and obtains / = 370 mm.

3. Finds the estimated belt length /> 1150 mm.

4. Measure the initial tension of the strap straps using loadings of known magnitude at the center of the strap and measure the transverse deflection of the strap and obtain Fo = 285 N.

5. Measures the idling speed of the transmission, the driving and driving shafts, the linear speed of the belt and calculates the repetitive speed of the belt, giving: «/ = 1500 min · '; «, = 720 min '¹; v = 7.4 m / s; f _apk = k * 6.5 Hz, where k = \, 2,3, ... n.

6. Calculate the linear density of the strap by weighing the strap and dividing the mass by the calculated length of the strap and obtains p = 0.1 kg / m.

7. Using the transverse vibration equation (1) of the longitudinally moving string, calculate the frequency of the transverse vibrations of the belt branches and obtain ^ = 72 Hz.

c'y et ²

-2v o ^: y ctcx

^{+ / 3} ^ ^{= Q} dt (1) where: β transverse vibration damping factor;

c ² = F () / p - velocity of belt wave propagation in the longitudinal direction; x - coordinate; Fo - initial tensioning force of the strap; p is the mass of the strap per unit length.

8. Using belt transmission data, identified by the excitation frequencies, form nomograms of the relationship between the frequency of the belt branch transverse oscillation as a function of the tension force and the linear velocity of the belt. The linear velocity of the belt is plotted along the axis of the nomogram and the frequency of the abscissa is plotted along the axis. The nomograms plot families of repetitive belt transfer excitation frequencies and belt branch transverse frequency curves. A perpendicular line is drawn from the axis of the nomogram that corresponds to the linear speed of the belt. The abscissae of the points of intersection of this perpendicular with the repetitive excitation frequency curves are informative diagnostic components of the vibration spectrum. Below are nomograms of the relationship between the belt transfer excitation frequencies and the belt transverse oscillation frequencies considered in the example.

Fig. L - Dependence of the repetitive frequencies of the belt and the frequency of the belt transverse oscillations determined by the tension force on the linear speed of the belt.

Fig.2 - Dependence of repetitive drive pulley revolutions and belt transverse oscillation frequency, determined by the tension force, on the linear speed of the belt.

Fig.3 - Dependence of the repetitive driving pulley speed and belt cross-oscillation frequency on the linear speed of the belt.

In Figures 1 to 3, the points of intersection of the vertical black line with the repeated excitation frequencies are highlighted by circles, squares, and crosses.

9. It shall then measure the vibration of the webbing transmission bearing and perform a spectral analysis of the signal and record the values of the informative components of the spectrum obtained, not less than 0.3 * // ', where / rf ⁽¹⁾ are considered basic. FIG. Figure 4 shows a vibration spectrum of a belt drive drive pulley bearing, which identifies and captures the components of the repeated belt drive excitation frequencies.

Fie. 4 - Repetition frequency of belt drive for drive and drive pulley excitation frequencies and component of belt transverse frequency: x - drive pulley; - drive pulley; - frequency of belt transverse vibrations.

10. Subsequently, during operation, periodically measure the bearing vibration, compare the values of the information components of the spectrum obtained with the base data and determine the magnitude and condition of the belt tension when the component of one of the system excitation frequencies increases by 15% or more. For example, in the present case of belt transmission, the vibrational measurement of the spectral component at 60 Hz determines from the nomogram (Fig. 2) that the current tension force of the belt is 230 N, and accordingly decides on the suitability of the belt for further use.

DEFINITION OF INVENTION

Claims (2)

DEFINITION OF INVENTION 1. A method of diagnosing a condition of a belt transfer belt, consisting of measuring the tension force of the belt and evaluating the condition of the belt, characterized by identifying by calculation and measurement the fundamental and repetitive frequencies of the new or post-repaired belt transmission. velocity relationship nomograms, measure belt transfer bearing vibration, perform spectral analysis of the signal, and record informative values of the resulting spectrum at values less than 0.3 * // ^υ and are considered basic, where f _d ^V} is the first eigenvalue of the belt transverse oscillations frequency. 2. A method as claimed in claim 1, comprising periodically measuring bearing vibrations during operation, comparing the values of the information components of the spectrum obtained with the base data and determining the magnitude and condition of the belt tension force. k = 9 k = 8 k = 7 k = 6 k = 5 k = 4