Inductive wheel-speed sensor for an improved output signal indicative of a rotational speed of a motor vehicle wheel

摘要

The inductive wheel-speed sensor registers the rotational speed of a motor vehicle wheel. The wheel is mounted on a hub, which is rotatably mounted on an axle journal. The sensor has a transmitter wheel that rotates with the wheel and that is formed by a sequence of regions of magnetizable material separated from one another by regions of non- magnetizable or barely magnetizable material. Two magnets are stationarily mounted such that their magnetic flux varies as the magnetized and non-magnetized portions of the transmitter wheel pass by, as the wheel rotates. The variation depends on the rotational speed. The magnetic flux change in the two (or more) magnets is registered coils which are disposed in the vicinity of the magnets. The output signal of the coils is fed to an evaluation device. Mounting is facilitated, an improved signal is provided, and temperature influences due to braking are reduced in that the transmitter wheel is disposed outside of the hub, remote from the wheel, and the magnet and coil pairs are mounted on the axle journal immediately adjacent to the transmitter wheel but separated from the latter by a narrow gap. The magnets are spaced from one another such that one magnet faces a magnetizable region while the other magnet faces a non-magnetizable region of the transmitter wheel.