Working Principle: In non-contact throttle position sensors, samarium-cobalt magnets work in conjunction with Hall elements. When the throttle shaft rotates, it drives the samarium-cobalt magnet to rotate along with it. The rotation of the magnet causes changes in the magnetic field. The magnetic field collector converts the horizontal magnetic field into a magnetic field perpendicular to the Hall element. The current in the Hall element is deflected due to the magnetic force, resulting in a potential difference across the Hall element and finally generating an analog signal of the output voltage.
Advantages: Samarium-cobalt magnets have relatively high magnetic field strength and stability, which can provide accurate magnetic field signals, ensuring precise measurement of the throttle position by the sensor and enabling accurate control of the engine’s intake air volume. Their high-temperature resistance enables them to work stably in the high-temperature environment of the engine compartment, and they are not prone to demagnetization, guaranteeing the reliability and durability of the sensor.
Wheel Speed Sensors
Working Principle: Wheel speed sensors usually operate based on the principle of electromagnetic induction. Samarium-cobalt magnets, as the magnetic field source, are installed opposite the induction coils in the sensor. When the wheel rotates, it drives the magnetic field generated by the magnet to change, thereby generating an induced electromotive force in the induction coil. The frequency of this electromotive force is proportional to the wheel speed, and the wheel speed can be obtained by measuring the frequency of the electromotive force.
Advantages: The high magnetic energy product of samarium-cobalt magnets enables them to generate a relatively strong magnetic field, improving the sensitivity of the sensor. It can accurately measure even when the wheel speed is low. Meanwhile, their good corrosion resistance and temperature stability allow them to adapt to various harsh road conditions and environmental conditions, ensuring the long-term stable operation of the sensor.
Vehicle Body Height Sensors
Working Principle: Linear Hall-type vehicle body height sensors utilize the characteristic that the output of Hall elements is proportional to the magnetic field. Through the design of a special magnetic circuit, the magnetic field passing through the Hall element is proportional to the angle of the rotating shaft. Samarium-cobalt magnets provide a stable magnetic field for the Hall element. When the vehicle body height changes, the internal mechanical structure of the sensor drives the relative position between the magnet and the Hall element to change, causing the Hall element to output different voltage signals, based on which the vehicle body height can be measured.
Advantages: Within the automotive working temperature range, samarium-cobalt magnets have a small temperature coefficient, which can ensure the stability of the magnetic field strength and improve the measurement accuracy of the sensor. Moreover, their stable and reliable performance enables them to provide a stable magnetic field for the sensor for a long time, reducing measurement errors caused by magnetic field fluctuations.
Steering Angle Sensors
Working Principle: Steering angle sensors are used to measure the rotation angle of a vehicle’s steering wheel. Samarium-cobalt magnets are used in conjunction with the angle measurement elements in the sensor. When the steering wheel rotates, the direction of the magnetic field of the magnet changes relative to the measurement element. The measurement element calculates the rotation angle of the steering wheel based on the changes in the magnetic field and converts it into an electrical signal that is transmitted to the vehicle’s electronic control unit.
Advantages: The high magnetic field strength and stability of samarium-cobalt magnets can ensure that the sensor can accurately measure under different steering angles, providing accurate angle information for the vehicle’s steering system. In addition, their strong anti-interference ability can effectively resist external electromagnetic interference, ensuring the accuracy and reliability of the sensor signals.
