Magnetic suspension type ultra-low-frequency vibration sensor

Abstract

The invention provides a magnetic suspension type ultra-low-frequency vibration sensor. The magnetic suspension type ultra-low-frequency vibration sensor comprises a housing, a cylindrical permanent magnet, an annular permanent magnet, electromagnetic coils and a photoelectric displacement detector. The conventional spring structure is replaced with a mixed structure of permanent magnetic and electromagnetic, and equivalent support stiffness and equivalent damp of a suspension system are reduced, so that mechanical inherent frequency of the system is effectively reduced, lower limit of ultra-low-frequency band measurement is greatly extended, and the size and the weight of the sensor are reduced. Multiple pairs of symmetric electromagnetic coils are mounted at the bottom of the sensor so as to support a mass block in a suspension way, and the photoelectric displacement detector is adopted to detect displacements in all directions to measure multi-directional torsional vibration parameters so as to further expand application range of the magnetic suspension type ultra-low-frequency vibration sensor. The magnetic suspension type ultra-low-frequency vibration sensor can satisfactorily meet requirements of the fields of national defense industry, aerospace, engineering measurement and the like on ultra-low-frequency vibration measurement, and effectively extends lower limit of ultra-low-frequency vibration measurement.

Description

technical field [0001] The invention belongs to the field of testing and measuring instruments, and specifically relates to a magnetic levitation ultra-low frequency vibration sensor, which is used in the fields of aero-engine monitoring, seismic wave detection, and vibration analysis of large-scale low-frequency structures, and uses a hybrid structure of electromagnetic and permanent magnets to replace the traditional spring structure. As a support guide. Background technique [0002] Ultra-low frequency vibration refers to vibration with a frequency between 0.01 and 20 Hz. This type of vibration has the characteristics of low vibration frequency, large vibration amplitude, and strong destructive power. The testing and research of ultra-low frequency vibration has always been highly valued in the fields of aerospace, defense industry, engineering measurement and biomedicine. The traditional ultra-low frequency vibration sensor uses a spring element as a supporting and guid...

AI Technical Summary

Problems solved by technology

The traditional ultra-low frequency vibration sensor uses a spring element as a supporting and guiding mechanism, but due to the limitation of the natural frequency of the spring itself, the natural frequency of the entire sensor is between 5 and 30 Hz, that is, it cannot distinguish signals below its natural frequency. range of its use

At present, the most common improvement method of this type of sensor at home and abroad is to widen its frequency response by connecting a compensation network in series behind the sensor, but the lowest can only reach about 0.1Hz. There are also ultra-low frequency sensors made of oblique springs and other structures, but Because the spring is too soft and the mass is too large, in addition to the bulky size of the sensor, the stability and reliability are also poor, so it cannot be widely used in the industrial field

For example, the 941B vibration pickup developed by the Institute of Engineering Mechanics of the China Earthquake Administration uses a series compensation network to broaden its frequency response. The lower limit frequency of its measurement is 0.1Hz, but its size is Φ70*80mm and its weight is 1.5kg. The weight is relatively large, which also limits its application to a certain extent.

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