E-bike speed sensor measures wheel speed for safe braking
Just as the anti-lock braking system (ABS) has become indispensable in passenger and commercial vehicles, so it is becoming increasingly popular for e-bikes where they are used to avoid accidents by uncontrolled braking, especially during emergency stops or braking on gravel and wet roads. The ABS ensures a safe slowdown by evenly de-accelerating the front and rear wheels. To do this, the speed on both wheels must be measured constantly and precisely. A Hall-based speed sensor from ZF, the GS82-AA02 e-bike speed sensor was especially developed for use in pedelecs and S-pedelecs.
Based on Hall technology, the sensor in combination with an external, ferromagnetic speed disc achieves a high-resolution speed measurement. The sensor targets the slot structure of the speed disc and, depending on the number of slots, transmits up to 50 or more speed signals per wheel revolution. This leads to a quicker response from the e-bike drive, said ZF. The ABS system also benefits from the high resolution in speed. With the precise speed values of both wheels, the ABS control unit can adjust the wheels to each other and brake them in a controlled manner.
The compact sensor design measures 21.75mm long and 9.35mm in diameter, for use in e-bikes. The Hall-effect speed sensor is contactless and wear-free. The differential measurement of the magnetic flux also increases the robustness of the sensor against vibrations. Depending on the customer’s requirements the contact via connector, as well as the cable length, can be pre-selected individually. The sensor requires a constant voltage supply of 6.5 to 20V DC and measures frequencies between 1.0 and 2,500Hz. They are designed for a temperature range from -25 to + 85 degrees C, as dictated by the e-bike industry.
ZF is a global technology company suppling systems for passenger cars, commercial vehicles and industrial technology, enabling the next generation of mobility. In the four technology domains of Vehicle Motion Control, Integrated Safety, Automated Driving, and Electric Mobility, ZF offers comprehensive product and software ranges for established vehicle manufacturers and newly emerging transport and mobility service providers. ZF electrifies a wide range of vehicle types, contributes to reducing emissions, protects the climate and enhances safe mobility.