ABS RING Magnetic encoders are generally evenly arranged with a number of staggered N-poles and S-poles on the outer surface. In automobile ABS system, magnetic encoders are generally installed on bearings. With the synchronous rotation of wheels and bearings, the N-pole and S-pole magnetic fields convert back and forth, and the magnetic field direction alternates to generate alternating pulse magnetic field. The change information of the magnetic field is transmitted to automobile ABS system, and the ABS system transmits the change information to automobile ABS system The change of wheel speed controls the brake system to prevent lock when braking.