CN86200400U - Pocket-size dynamic balance instrument - Google Patents

Abstract

The utility model discloses a pocket-size dynamic balance instrument which belongs to the field of the dynamic unbalance signal analyzer. The filter circuit of the utility model is composed of a switch resistance tracking filter whose two stages Q value is 3-5 and a narrowband N branching filter whose two stages are connected in parallel, and the narrowband N branching filter is provided with a 0.5-2Hz band-width. The parallelly connected narrowband N branching filter can effectively filter all even harmonic interferences and the near-by frequency noise in the vicinity of a centre frequency. Therefore, the requirements of the switch resistance and the tracking filter Q value can be degraded to repress the influence of the an output phase from the environment temperature change. The utility model can be used for the spectrum analysis of the vibration signal and the dynamic balance on site of the rotary mechanism rotor.

Description

Pocket-size dynamic balance instrument

The utility model belongs to unbalance dynamic analysis of vibration signal instrument field.

The pick-up sensor is in the rotary machine rotor vibration detection process, not only detect since amount of unbalance cause with rotor speed with signal frequently, but also can detect various interference noises.Sometimes, the signal that these interference-to-noise ratio amount of unbalances cause is much bigger, even floods the unbalance information that will extract.Therefore, in the dynamic balancing technics process, needing a kind of the device can be under the noise background of complexity, accurately extracts vibration amplitude and phase place that the imbalance of rotor causes, as the reference information of eliminating the caused vibration of amount of unbalance.

At present, the most correlation filtering principles that adopt of this quasi-instrument.The DEp-E dynamic balance instrument that Japan alum company produces adopts the square wave relative theory.It carries out cross correlation process with the reference square wave and the vibration signal of photoelectric sensor output, and the result has kept both common frequency contents, filtering other interference.Because of containing each time odd harmonic of fundamental frequency (with rotor speed frequency together) composition and fundamental frequency in the reference square wave, so when comprising the odd frequency multiplication interfering components of fundamental frequency in the measured signal of pick-up sensor, will be detected with the signal that amount of unbalance causes.Therefore can influence balance efficiency.The DEp-E dynamic balance instrument can be used for spot dynamic balance.Operating frequency range be 3Hz-1000Hz phase angular accuracy be ull-scale value ± 10%.This instrument filtering odd frequency multiplication interference performance is poor, and the phase angular accuracy is lower.The general vibration analyzer of ZDF-1 that China produces adopts the switch resistance tracking filter as main filtering link, and it has filtering odd and even-order harmonic interference capability, but near the nearly frequency the filtering centre frequency disturbs, the Q value need be done than higher.Therefore, its phase-frequency characteristic changes violent at the centre frequency place, make signal phase be subjected to the influence of environment temperature easily.

The utility model provides a kind of portable dynamic balance instrument.It has following function and performance:

1, when using as dynamic balance instrument, can be from the rotating speed of motion tracking rotary machine rotor, realize tracking filter, suppress various interference effectively, suppress the influence of temperature to phase place, operating frequency range is 3Hz-1000Hz, and phase accuracy is less than ± 3 °, low price only is about 1/3rd of a DEp-E dynamic balance instrument.Having amplitude, phase angle, rotating speed output and numeral shows.

2, manual frequency sweep knob is set on the panel, can changes reference signal frequency, vibration signal is carried out analysis of spectrum.When making analysis of spectrum, can provide output of amplitude and rotating speed and demonstration.

The utility model is composed in series by the switch resistance tracking filter of one-level Q value 3-5, the N branching filter of two-stage parallel connection.Two-stage N branching filter bandwidth is 0.5～2Hz, because near the nearly frequency interfering components the fine filtering centre frequency of the very narrow energy of passband.The N branching filter that comprises 16 branch roads, the conducting successively of its every branch road is by the f of phaselocked loop output ₀, 2f ₀, 4f ₀, 8f ₀Coding decision.It only exports the signal of fundamental frequency and all integer frequencies.Another N branching filter is made up of 8 branch roads, and the conducting successively of each branch road is by 2f ₀, 4f ₀, 8f ₀The coding decision.It only exports all even number frequency-doubled signals of fundamental frequency.The output of two N branching filters is subtracted each other can eliminate all even-order harmonics interference.The first order and second level switch resistance wave filter, because the Q value is 3～5, its phase-frequency characteristic curve changes slowly in centre frequency, so the phase place of output signal is not subject to the influence of variation of ambient temperature.This two-stage switch resistance tracking filter parameter is identical, and when the Q value was 3, its amplitude versus frequency characte was shown below:

$\left|K\left(\mathrm{j\ω}\right)\right|=\frac{1.71\frac{\mathrm{\ω}}{{\mathrm{\ω}}_0}}{\sqrt{{[1-{\left(\frac{\mathrm{\ω}}{{\mathrm{\ω}}_0}\right)}^2]}^2+{\left[0.286\frac{\mathrm{\ω}}{{\mathrm{\ω}}_0}\right]}^2}}$

In the formula: | K(j ω) |---amplitude versus frequency characte

ω ₀---the centre frequency of wave filter

Because two-stage switch resistance tracking filter series connection, its transport function is the relation of multiplying each other, can calculate two-stage Q value by following formula is that 3 switch resistance tracking filter can make the frequency tripling amplitude attenuation about 70%, makes five frequency multiplication amplitude attenuations 90%, and other strange frequency multiplication will decay manyly.

Fig. 1 has provided the utility model schematic circuit.

First order switch resistance tracking filter (1) among Fig. 1 is identical with second level switch resistance tracking filter (6) circuit and parameter.They all form the logical circuit of basic band by three CD3140 high input impedance operational amplifiers.One of element of decision bandpass filter centre frequency is the input current potential of integral unit, and it is realized by switch CD4052 and a resistance in series R.The pass resistance break of CD4052 is very big, and conducting resistance is very little, is a comparatively desirable switch, owing on its integrated chip of four switches, have good symmetry, is convenient to the circuit debugging again.Again because it has V _EEEnd can connect-the 12v power supply, so it has ± the 12v dynamic range.128 frequencys multiplication of phaselocked loop (7) output reference signal after monostable 4098, to the coding side of CD4052, have realized the variation of integral unit input resistance, reach and follow the tracks of the purpose that extraneous frequency input signal changes.(2) are the N branching filters that contains 16 branch roads among Fig. 1, and it is by two CD4051 switches, and external 16 electric capacity and a resistance are formed.Same CD4051 closes that resistance break is very big, and conducting resistance is very little, also is a comparatively ideal switch, and it has the VEE power end, can connect-12v, and its dynamic range can be between ± 12, the conducting successively of N each branch road along separate routes, the 2f that is drawn by phaselocked loop (7) ₀, 4f ₀, 8f ₀Coding and f ₀And f ₀Through phase inverter (8) output decision.(3) among Fig. 1 are the N branching filters that contains 8 branch roads, are made up of a slice CD4051,8 electric capacity and a resistance.Phase inverter (4) is given in the N branching filter output that contains 8 branch roads, sends into summer (5) simultaneously with the output of the N branching filter (2) with 16 branch roads then, disturbs to eliminate even-order harmonic.

Therefore, the utility model first order switch resistance tracking filter (1) and second level switch resistance tracking filter (6) can fine inhibition high frequency and odd harmonic disturb, and the even-order harmonic interference is eliminated in the combination that has the N branching filter (2) of 16 branch roads and have a N branching filter (3) of 8 branch roads. Each N branching filter can also suppress near frequency interference simultaneously. These two kinds of wave filters interosculate and replenish, and have both improved filter capacity, suppress again environment temperature to the impact of phase place. In addition, because switch resistance wave filter (6) sample frequency is 128f₀, can play the along separate routes smoothing effect of output waveform to N, be conducive to improve the phase angular resolution.

Claims (1)

1, a kind of portable dynamic balance instrument, its main circuit be by secondary switch resistance tracking filter [1,6], two-stage arrowband N branching filter [2,3] and phaselocked loop [7], and phase inverter [4,8], summer [5] is formed, it is characterized in that,

A, first order switch resistance tracking filter [1] (Q=3～5) are connected to the N branching filter [2] with 16 branch roads that two-stage is in parallel, (bandwidth is 0.5～2Hz) to the N branching filter [3] of 8 branch roads, through phase inverter [4], summer [5] is in series with second level switch resistance tracking filter [6] (Q=3～5)

B, the N branching filter [2] that contains 16 branch roads are in parallel with the N branching filter [3] that contains 8 branch roads, disturb f., 2f., 4f., the 8f of phaselocked loop [7] output to eliminate even-order harmonic through phase inverter [4] and summer [5].Signal is delivered to switch CD4051 and is encoded, and makes N each branch road conducting successively along separate routes,

C, in two switch resistance tracking filters [1,6], select for use CD4052 as switch because CD4052 makes four switches on chip piece, have good symmetry, CD4052 has V _DD, V _EEPower end can connect+12V and-12V power supply, has bigger dynamic duty scope.

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