Wheel speed detection system

申请公布号：

US2006052928(A1)

申请号：

US20050542054

申请日期：

2005.07.12

申请公布日期：

2006.03.09

申请人：

KAWASAKI NORIFUMI;KITA HIDEO

发明人：

KAWASAKI NORIFUMI;KITA HIDEO

分类号：

B60T8/32;G01P3/481;G01P3/49

主分类号：

B60T8/32

摘要：

In a wheel speed detection system wherein an eddy current displacement sensor is used, even when a distance between the eddy current displacement sensor and a convex portion of a rotator changes due to a change in load on a wheel, an error in a wheel assembly during a maintenance or other reasons, wheel speed can be detected accurately. Sensor detection voltage corresponding to an impedance change of a detection coil ( 11 ) generated in association with wheel rotation is inputted into a signal processing device ( 20 ). In a signal level determination unit ( 22 ), threshold voltages (V<SUB>TH </SUB>and V<SUB>TL</SUB>) are calculated based on sensor detection voltage after A/D conversion. Specifically, the difference between the average of sensor detection voltage, when the facing distance between a sensor head ( 10 a) and a convex portion ( 7 a) is a preset default facing distance (d<SUB>0</SUB>), and the average of actual sensor detection voltage is obtained, and preset threshold voltages are shifted for the difference. Thereby, irrelevant to a change in the above-mentioned facing distance, sensor detection voltage can be converted into pulse signals by the constantly appropriate threshold voltages.