Tachometer based on AMR magnetic resistance switch chip and production method thereof

Abstract

The invention discloses a tachometer based on an AMR magnetic resistance switch chip and a production method thereof. The production method thereof comprises steps that a permanent magnet is fixedly disposed next to the AMR chip, and magnetic flux passing through the MAR chip can reach a saturated state by adjusting angles, and at the same time, the chip is used to output a low level signal; when the cam shaft of the motor rotates along with rotation of a motor rotor, and passes by the chip, the magnetic flux passing through the AMR chip is in an unsaturated state, because the gear on the cam shaft adopts magnetic conductive materials, and at that time, the chip is used to output a high level signal; under the rotation of the motor rotor, a series of pulse signals are output by the chip, and the rotating speed of the motor can be calculated according to the signals. The tachometer has advantages of simple structure, small size, low requirement on installation environment, and wide application environment.

Description

technical field [0001] The invention relates to a tachometer based on an AMR reluctance switch chip and a manufacturing method thereof, belonging to the technical field of vehicle equipment preparation. Background technique [0002] The application of automobiles in today's society has become very common. With the development of the automobile industry, some supporting equipment for automobiles has gradually developed and expanded. Among them, tachometers and speedometers are an indispensable part of automobiles, which shows that the design It is very necessary to develop a new and practical tachometer and speedometer. Currently, the automotive tachometer and speedometer sensors used in the market are mainly divided into two types: contact type and non-contact type. The main working principle of the contact type speed sensor is The sensor is in direct contact with the moving object. When the moving object is in contact with the rotary speed sensor, the friction force drives ...

AI Technical Summary

Problems solved by technology

[0003] Although the above method has been widely used in practical applications, there are still certain problems in use. For the contact tachometer, it is easy to wear and tear during use, resulting in inaccurate measurement or even damage. This type of sensor It is generally used in low-end electric car toys; for photoelectric vehicle speed sensors, due to the complex supporting circuits and large volume, the space requirements for installation are high, which greatly limits the photoelectric speed sensor. The use of the vehicle speed sensor; for the magnetoelectric vehicle speed sensor, since its working principle is to measure the voltage change caused by the change of the magnetic flux, when the rotor speed is low, the signal voltage generated is small, which may lead to no detection signal, and when the rotor speed is too fast, the generated voltage signal is large, which may reach the maximum value of subsequent circuit processing, resulting in signal distortion and inaccurate measurement; and for the most widely used Hall sensor at present, due to The driving magnetic field of the Hall sensor is relatively large (generally above 40 Oe), the hysteresis is relatively large (generally above 8 Oe), and the quiescent current is relatively large (generally 10mA), which makes this type of sensor be applied at a higher speed In the environment, there is a response delay or even no response, which is more difficult to apply to some models that require a higher speed

Moreover, the Hall sensor requires more additional devices and a larger driving magnetic field, which requires a permanent magnet with a larger magnetic field, which increases the volume of the magnet and makes it inconvenient to install.

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