CN85102388B - Eddy current mode displacement transducer with high precision and high sensitivity - Google Patents
Eddy current mode displacement transducer with high precision and high sensitivityInfo
- Publication number
- CN85102388B CN85102388B CN 85102388 CN85102388A CN85102388B CN 85102388 B CN85102388 B CN 85102388B CN 85102388 CN85102388 CN 85102388 CN 85102388 A CN85102388 A CN 85102388A CN 85102388 B CN85102388 B CN 85102388B
- Authority
- CN
- China
- Prior art keywords
- coil
- sensor
- magnetic test
- magnetizing coil
- test coil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
The present invention relates to a sensor with high precision and high sensitivity, which adopts the structure of double coils with stronger variable exciting currents and weak coupling. An L-(1) L-(2) C-(1) C-(2) series parallel network is formed, the amplitude of the voltage of a used high frequency oscillator is stable, and an amplitude limiting method with high precision is adopted. Thus, each index of instruments is improved greatly. The sensor with high precision and high sensitivity can be used for the analysis of the revolving precision of various mechanical main shafts, the measurement of vibration, the measurement of axial position displacement, the on-line measurement of the thickness of metal plates, etc.
Description
The present invention is the surveying instrument that belongs to a kind of non-contact measurement relative displacement, amplitude.It can be for various mechanical spindle rotaring precision analyses, the measurement of various variation of axial positions, the measurement of steel plate thickness, the main shaft monitoring of the on-line measurement of stock removal and chemical industry, oil, power station main equipment etc.
Before the present patent application, Japanese application for a patent for invention (the clear 57-200803 of JP-) discloses a kind of employing high frequency oscillator provides high-frequency excitation, and the eddy current mode displacement measuring instrument of magnetizing coil and magnetic test coil is housed.Inside, outside, and not in a plane, magnetizing coil is that steady current is excitatory to magnetic test coil to this instrument magnetizing coil.Cell winding is during away from tested metal material, and magnetic test coil induced voltage is little; On the contrary, during near tested metal material, destroy magnetic circuit balance, magnetic test coil induced voltage is high.Because sensor output voltage is little and there have to be non-linear, therefore, to add radio-frequency amplifier after sensor and amplify, and electronics linearizer.
This measuring instrument is in order further to improve sensitivity, resolution and the linearity, adopt the twin coil (being magnetizing coil and magnetic test coil) of special construction, the method that exciting curent is variable, oscillator has adopted the quartz oscillator of high stability, and utilize accurate stabilivolt double limiting, make oscillator there is higher frequency and the stability of amplitude, and there is stronger load capacity.Before detector stage, do not need to add high frequency amplified signal level and amplify, and whole instrument do not need to add linearizer, just can make the item indexs such as the sensitivity, resolution, the linearity, temperature coefficient of whole instrument improve widely.
Eddy current mode displacement measuring instrument of the present invention, is that to utilize strong high-frequency current to carry out excitatory, and exciting curent size increases and automatically increases with displacement.In order to improve sensitivity and resolution, the coil of sensor comprises magnetizing coil L
1with magnetic test coil L
2, and make L
1l
2for weak coupling, L on circuit
1with resonant capacitance C
1coupled in series, L
2with resonant capacitance C
zparallel connection, forms a network jointly.In measurement, when sensor is during away from tested metal, make magnetizing coil approach series resonance state, magnetic test coil approaches parallel resonance state.Crystal oscillator has adopted accurate amplitude limit structure to come stabilized frequency and amplitude, and therefore the taking-up signal of sensor is very high, and the linearity is good, and the indices of sensor has improved widely.Distinguish that with the eddy current mode displacement measuring instrument best result of this sensor manufacture power reaches 0.01 μ (dynamically), when range is 1000 μ, resolution reaches 2 × 10
-5, the linearity is 0.5%, and when range is 200 μ, the linearity is 0.2%, and when range is 20 μ, the linearity is 0.5%, and the temperature drift of transducer is 0.01%/℃.
Fig. 1 is eddy current mode displacement measuring instrument block scheme;
Fig. 2 is high precision fixed ampllitude and power circuit;
Fig. 3 is twin coil principle of work;
Fig. 4 is twin coil installation site diagram.
Describe the embodiment of the present invention in detail below in conjunction with each accompanying drawing:
In Fig. 1, the power stage of oscillator is supplied with sensor magnetizing coil one high-frequency excitation electric current, at the anterior high frequency magnetic field that produces of cell winding, when sensor and tested metal material near time, due to high-frequency vortex effect, according to the law of electromagnetic induction, affect conversely the variation of cell winding parameter, cause that sensor magnetic test coil two ends output voltage changes, displacement amplitude signal is converted to the variable signal of HF voltage amplitude, amplify through detection and voltage power, give digital display circuit and carry out numeral demonstration.
In Fig. 2,17,18 is amplitude limit voltage stabilizing diode, the negative reference voltage source of 2,3,4,5,6,7 composition, and the positive reference voltage source of 9,10,11,12,13,14 composition, 27 is current-limiting resistance, 19,20,21,22,23,24,25 is power output circuit.In Fig. 2,15 ends are input high-frequency signals, by voltage stabilizing diode 17,18 double limitings, because voltage stabilizing diode selects its voltage breakdown (voltage stabilizing) value higher, for 6V left and right, for obtaining more suitable voltage amplitude, adopt accurate reference voltage and voltage stabilizing diode to form accurate amplitude limit.
In Fig. 3, L
1magnetizing coil, L
2magnetic test coil, C
1, C
2it is resonant capacitance.L
1with C
1coupled in series, L
2with C
2parallel connection.While measurement, when sensor is during away from tested metal material, L
1l
2c
2be perception, C
1for capacitive, from L
1l
2c
1c
2the entirety of structure is seen, approaches series resonance state, L
2c
2approach parallel resonance state, at this moment L
1in high-frequency excitation electric current large, and more much bigger than imbalance state exciting curent, L
1both end voltage is higher, due to L
1l
2be the connection form of boosting, and turn ratio is 1: 5, L
1l
2for weak coupling, just make C
2both end voltage is quite high; On the contrary, when sensor is during near tested metallics, because eddy effect makes L
1l
2equivalent electric sensibility reciprocal reduces, and loss resistance increases, and network is in imbalance state, and exciting curent reduces, and therefore sharply destroys L
1l
2coupling coefficient M, make C
2both end voltage drops to very low value, and when sensor is near tested metal object, output voltage is low; Sensor is during away from tested metal, and output voltage is high.Therefore the exciting curent size of sensor increases and automatically increases with the distance of sensor and tested metal.So that sensor has high sensitivity and resolution, and the linearity that had of sensor itself, instrument does not need to add electronics linearizer.
Referring to Fig. 4, in the time manufacturing sensor, twin coil L
1l
2on high-frequency ceramic skeleton 31, additional protective seam 32.In order to improve the sensitivity of sensor, adopt plane magnetic test coil, coil groove is very narrow, and in this groove, magnetizing coil is around outside, and magnetic test coil is around the inside.Because the remolding sensitivity of sensor itself is higher, require the temperature stability of coil itself to get well, therefore coil is cemented on the smaller high-frequency ceramic of expansion coefficient.This pickup wire loop diameter is 8 millimeters of φ.
Claims (4)
1. a current vortex displacement amplitude measurement instrument utilizes high-frequency vortex effect, amplitude modulation method that displacement is converted to corresponding electric weight to carry out displacement amplitude non-contact measurement, it comprises high frequency oscillator, the sensor being formed by magnetizing coil and magnetic test coil and amplification output circuit, high frequency oscillator is supplied with high-frequency current of sensor magnetizing coil, on magnetic test coil, take out signal, after detection, carry out voltage and power amplification, and send digital demonstration, the invention is characterized in:
A) above-mentioned high frequency oscillator adopts quartz oscillator and exports to sensor magnetizing coil through double limiting circuit and power amplification circuit;
B) magnetizing coil (L of the sensor
1) and resonant capacitance (C
1) coupled in series, magnetic test coil (L
2) and resonant capacitance (C
2) parallel connection, jointly form a network, when this sensor is during away from tested metal material, L
1c
1approach series resonance state, L
2c
2approach parallel resonance state, exciting curent strengthens, and makes L
1l
2for the form of boosting, C
2two ends output voltage increases; And when sensor is during near tested metal object, due to eddy current effect, network imbalance, exciting curent reduces, and sharply destroys magnetizing coil (L
1) and magnetic test coil (L
2) coupling coefficient, resonant capacitance (C
2) both end voltage drops to very low value.
2. measuring instrument according to claim 1, is characterized in that, magnetizing coil becomes planar coil form with magnetic test coil in the narrow groove of high-frequency ceramic skeleton, magnetizing coil (L in this groove
1) around outside, magnetic test coil (L
2) around the inside.
3. according to the measuring instrument described in claim 1 and 2, it is characterized in that magnetizing coil (L
1) and magnetic test coil (L
2) adopt weak coupling, and turn ratio is 1: 5.
4. measuring instrument according to claim 1, is characterized in that, above-mentioned crystal oscillator has adopted the amplitude limiter circuit of accurate reference voltage circuit and limiter diode (17), (18) and current-limiting resistance (27) composition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85102388 CN85102388B (en) | 1985-04-10 | 1985-04-10 | Eddy current mode displacement transducer with high precision and high sensitivity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85102388 CN85102388B (en) | 1985-04-10 | 1985-04-10 | Eddy current mode displacement transducer with high precision and high sensitivity |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85102388A CN85102388A (en) | 1986-04-10 |
| CN85102388B true CN85102388B (en) | 1987-10-07 |
Family
ID=4792471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 85102388 Expired CN85102388B (en) | 1985-04-10 | 1985-04-10 | Eddy current mode displacement transducer with high precision and high sensitivity |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN85102388B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004047116A1 (en) * | 2004-03-08 | 2005-10-06 | Micro-Epsilon Messtechnik Gmbh & Co Kg | Method and device for non-contact speed measurement |
| CN105277109B (en) * | 2015-09-02 | 2017-01-25 | 西南交通大学 | Displacement sensor outputting digital frequencies |
| CN105403232B (en) * | 2015-11-30 | 2018-11-02 | 国家电网公司 | Novel eddy-current sensor combines the unit |
| CN105783692B (en) * | 2016-05-17 | 2018-08-24 | 广东省智能制造研究所 | A kind of eddy current displacement sensor and implementation method |
-
1985
- 1985-04-10 CN CN 85102388 patent/CN85102388B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN85102388A (en) | 1986-04-10 |
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Legal Events
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| SE01 | Entry into force of request for substantive examination | ||
| C06 | Publication | ||
| PB01 | Publication | ||
| C13 | Decision | ||
| GR02 | Examined patent application | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |