Giant magnetic sensor and velocity measurement mechanisms

Abstract

4 or 6 groups of giant magnetoresistances are fixed on the substrate of this giant magnetic sensor, and each group has 4 to 24 giant magnetoresistances. The other ends of the giant magnetoresistances in each group are connected to be output ends. The giant magnetic sensor speed measuring mechanism comprises the above-mentioned giant magnetic sensor, a magnetic drum, and a microprocessor circuit module. The rotating shaft of the magnetic drum is drivingly connected with the object to be measured. The giant magnetic sensor is fixed 0.05-0.15mm away from one side of the magnetic drum, and the giant magnetic sensor is connected to the microprocessor circuit module through the amplifying circuit. The magnetic drum rotates synchronously with the object to be measured, the magnetic field around it changes, and the resistance value of the giant magnetic sensor changes accordingly, and the signal is sent to the microprocessor to obtain the speed of the rotating moving object. The microprocessor automatically selects the subdivision magnification according to the signal frequency, which can adapt to the detection of different speeds from 1 to 5000 rpm, and the resolution is higher than 3.6×10-5 radians, with strong anti-interference ability and high impact resistance. environment to work normally.

Description

(1) Technical field [0001] The invention relates to the technical field of speed measurement, in particular to a giant magnetic sensor and a non-contact rotational motion speed measurement mechanism made by using the giant magnetic sensor. (2) Technical background [0002] Giant Magneto Resistive (GMR) for short, is a high-tech product integrating magnetic thin film, semiconductor integration and nanotechnology. GMR has a large resistance effect under the action of a magnetic field. The magnetoresistance value of alloy materials is about ten times higher. Therefore, compared with photoelectric sensors, sensors made by GMR have the advantages of high resolution, strong reliability, low-speed static detection, fast response, long detection distance, wide frequency bandwidth, small power consumption, small size, and can work in harsh environments. In recent years, it has attracted attention, and GMR current sensors, GMR displacement sensors, etc. have been introduced. If the ...

AI Technical Summary

Problems solved by technology

As far as the most commonly used tachogenerators, grating encoders, and AMR magnetic encoders are compared, the low-speed and high-speed characteristics of the tachogenerator are not good.

The grating encoder overcomes the shortcomings of the tachogenerator, but it has poor weather resistance and is susceptible to moisture and mildew, thus affecting the accuracy

Anisotropic MagnetoResistive AMR (Anisotropic MagnetoResistive) magnetic encoders can work in harsh environments, but the fly in the ointment is that the resolution of AMR magnetic encoders is not high. At present, the magnetic sensors made of traditional AMR materials in the world have a magnetic field resolution index It is 40 microgauss, so the magnetic poles of the magnetic drum should not be too narrow, that is, under limited conditions, the number of magnetic pole pairs should not be too much

In this way, under the same scale conditions, the AMR magnetic encoder does not output as many pulses as the grating encoder, that is, the accuracy is lower

Images