Wheel speed sensor (wheel speed sensor for short) Electromagnetic induction wheel speed sensor is installed in automobile anti-skid control system. It can be installed on the wheel, or in the main reducer or transmission.
The wheel speed sensor is usually located at the position of the front wheel brake disc. The wheel speed sensor is installed on the hub of each wheel, but some imported cars are not necessarily.
Some rear-wheel drive cars only have an electromagnetic induction speed sensor in the main reducer or transmission.
The sensor is installed on the main reducer housing or the transmission housing, and the gear ring is installed on the main reducer input shaft or the transmission output shaft. It provides signals to the ABS braking system to control the braking force.
Front wheel speed sensor installation position rear wheel speed sensor installation position wheel speed sensor type magnetoelectric wheel speed sensor: Magnetoelectric wheel speed sensor structure: It is mainly composed of permanent magnet, polar axis and induction coil, and also divided into chiseled, cylindrical and diamond forms.
Its advantages are simple manufacturing cost, simple manufacturing structure and no fear of oil sludge. Its disadvantage is that the frequency response is not very high. When the vehicle is driving at high speed, the response frequency can't keep up, which will also produce error signals. The anti-electromagnetic interference ability is very poor, and the output signal amplitude is relatively small.
Principle of magnetoelectric wheel speed sensor: It mainly consists of two parts: a permanent magnetic core and a coil. The magnetic field lines mainly come out through one pole of the magnetic core, pass through the gear ring and air, and then return to the other pole. Whenever the wheel is running, it will change its reluctance through the induced magnetic field in turn, which will lead to the corresponding change of potential. Each frequency and amplitude reflects the speed at which the wheel rotates.
Hall wheel speed sensor: The Hall wheel speed sensor consists of a sensing head and a gear ring, and the sensing head also consists of a permanent magnet, a Hall element and an electronic circuit.
This kind of sensor is mainly made by using the principle of Hall effect. Its advantages are that the amplitude of output signal voltage is not affected by rotating speed, high frequency response and strong anti-electromagnetic interference ability.
Principle of Hall wheel speed sensor: The current is mainly controlled by both ends of the semiconductor, and a magnetic field is applied in the vertical direction of the wafer. At this time, a potential will be generated at both ends of the wafer to control the current and magnetic induction intensity. The output of the signal mainly depends on the magnetic induction intensity, and the Hall potential pulse is generated by the change of the input intensity. It mainly performs amplification, shaping, power amplification and other functions, and reflects the speed of wheel rotation through pulse frequency.
(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)