Front ABS sensor line
The abs sensor is used in the ABS (Anti-lock Braking System) of a motor vehicle. Most of the ABS system is monitored by an inductive sensor to monitor the vehicle speed. The abs sensor outputs a set of accurate The frequency and amplitude of the sinusoidal alternating current signal are related to the wheel speed. The output signal is transmitted to the ABS electronic control unit (ECU) to realize real-time monitoring of the wheel speed.
main species
1. Linear wheel speed sensor
The linear wheel speed sensor is mainly composed of a permanent magnet, a pole shaft, an induction coil and a ring gear. When the ring gear rotates, the tooth tops and backlashes face the polar axis alternately. During the rotation of the ring gear, the magnetic flux inside the induction coil changes alternately to generate an induced electromotive force, and this signal is input to the ABS electronic control unit through the cable at the end of the induction coil. When the speed of the ring gear changes, the frequency of the induced electromotive force also changes.
2. Ring wheel speed sensor
The annular wheel speed sensor is mainly composed of a permanent magnet, an induction coil and a ring gear. The permanent magnet is composed of several pairs of magnetic poles. During the rotation of the ring gear, the magnetic flux inside the induction coil changes alternately to generate an induced electromotive force. This signal is input to the ABS electronic control unit through the cable at the end of the induction coil. When the speed of the ring gear changes, the frequency of the induced electromotive force also changes.
3. Hall wheel speed sensor
When the gear is at the position shown in (a), the magnetic force lines passing through the Hall element are dispersed, and the magnetic field is relatively weak; while when the gear is at the position shown in (b), the magnetic force lines passing through the Hall element are concentrated, and the magnetic field is relatively strong . When the gear rotates, the density of the magnetic flux passing through the Hall element changes, thus causing a change in the Hall voltage, and the Hall element will output a quasi-sine wave voltage of millivolt (mV) level. This signal also needs to be converted into a standard pulse voltage by an electronic circuit.
Install Edit Broadcast
(1) Stamping ring gear
The ring gear and the inner ring or the mandrel of the hub unit adopt an interference fit. During the assembly process of the hub unit, the ring gear and the inner ring or the mandrel are combined together by a hydraulic press;
(2) Install the sensor
There are two forms of cooperation between the sensor and the outer ring of the hub unit: interference fit and nut locking. The linear wheel speed sensor is mainly in the form of nut locking, and the annular wheel speed sensor adopts interference fit;
The distance between the inner surface of the permanent magnet and the tooth surface of the ring gear: 0.5±0.15mm (mainly ensured by controlling the outer diameter of the ring gear, the inner diameter of the sensor and the concentricity)
(3) Test voltage Use the self-made professional output voltage and waveform at a certain speed, and test whether there is a short circuit for the linear sensor;
Speed: 900rpm
Voltage requirement: 5. 3～7. 9v
Waveform requirements: stable sine wave
voltage detection
Output voltage detection
Test items:
1. Output voltage: 650～850mv(1 20rpm)
2. Output waveform: stable sine wave
Second, abs sensor low temperature durability test
Keep the sensor at 40°C for 24 hours to check whether the abs sensor can still meet the electrical and sealing performance requirements for normal use
