The side of vibration signal of hydraulic pump shell is briefly described

Overview of vibration monitoring for 1. hydraulic pumps

The vibration signals generated by the hydraulic components during movement are transmitted to the surface of the shell. The state of the various components will cause the difference of the vibration signal by the sensor and the vibration signal measured vibration meter, and recorder recorded by spectrum analyzer spectrum transform, the frequency distribution of the image of hydraulic components of vibration energy (spectrum). The frequency spectrum of the vibration signal on the spot is compared with the standard spectrum (the spectrum in the normal state and the typical spectrum of fault spectrum), and the spectrum of the spectrum is closest to that of the spectrum so that the state of the component can be judged.

The frequency spectrum analysis can also judge whether the component is faulty according to the peak value of the characteristic spectrum.

Vibration analysis example of 2.ZB40 axial piston pump

(L) the detection method test system is shown in figure 3-11. The vibration signal of the pump housing, the acceleration sensor and converted into electric signals, the impedance converter discovery into vibrometer, and converted to voltage signal by amplifying the input to the tape recorder to record, and then use the HP3582A spectrum analyzer for analysis and processing, draw the spectrum.

The main fault of ZB40 pump is the valve plate and the swash plate copper copper. The experiment concluded that the oil pan side casing of the measuring points of vibration signals is the best measuring point here, sensors can reflect both the oil pan with copper and copper swash plate two faults, and the signal-to-noise ratio.

(2) according to the test results of two Liuhe copper parts of ZB40 pump, the experiments were performed according to 4 modes, including normal pump, oil pan copper copper fault fault, swash plate and the inclined plate at the same time, with the copper fault. After testing and spectrum conversion, the power spectrum of the 4 states of the pump is obtained, as shown in figure 3-12. The abscissa in the figure represents the frequency value 0~1000Hz, and the ordinate represents the power spectrum value, in terms of energy.

From these 4 power spectra, it can be seen that the normal pump energy is concentrated in the fundamental frequency, the 2 octave and the 3 octave, and there is little difference in energy between the 3 frequency points. With oil pump fault energy concentrated in the fundamental frequency and the 4 frequency, the other frequency points relatively little energy. The energy of the swashplate fault pump is concentrated on the fundamental frequency and the 2 octave, but the fundamental energy is much larger than the 2 octave energy, and the energy at the high frequency is very small. The oil pan and the swash plate synchronizebreakdown pump, energy concentrated in 4 times, 5 times, less low-frequency energy.

The analysis of these spectra shows that there is an inevitable connection between the power spectrum and the fault. The vibration of the normal pump is related to the plunger, and the vibration frequency is based on the base. Besides the frequency division, there is harmonic component, so the energy is concentrated on the fundamental frequency and the low frequency. With oil pump fault energy concentrated in the fundamental frequency and the 4 frequency, because copper faults with oil pan is in the end face of the cylinder and valve plate, and the surface contact, the vibration signal for broadband signal, for harmonics, so in addition to the inherent frequency of pump, the 4 octave has focused a lot of energy. Swash plate pump fault energy on the pitch, because the swash plate failure is a bit sticky copper (plunger oil to the transition point from the row of oil on the 7), the slipper sliding on the swash plate through the fault point frequency is just equal to the fundamental frequency, and strengthen the fundamental points of energy, other frequency the energy decreases. With oil pan and the swash plate and the miasma of pump, energy concentrated in the high frequency, low frequency energy is small, because the two are in trouble at the same time, the vibration of the shell as a result of integrated effect, the comprehensive effect can be used to explain the vibration state of the cylinder, the cylinder is in contact with the oil pan, the other end of the plunger contact with the swash plate and the inclined plate, when faults occur at the same time, the vibration state of both ends of the cylinder are changed, the comprehensive effect, the fundamental vibration original damage, energy concentrated in high frequency.