Patent ID: 6879149

Claim:
An anti-skid braking device for, by detecting a rotational speed of a wheel rotatably supported by an automotive body structure using a wheel support bearing assembly rotatably supporting a wheel relative to an automotive body structure and comprising an outer member having an inner peripheral surface formed with plural rows of raceways, an inner member having raceways defined therein in face-to-face relation with the raceways in the outer member, plural rows of rolling elements accommodated between the raceways in the outer and inner members, an electric generator generating an electric power as one of the outer and inner members rotates relative to the other of the outer and inner members, and a wireless transmitter transmitting wireless a signal indicative of a number of revolutions of the wheel that is outputted from the electric generator, controlling a braking force in response to a detection signal indicative of the rotational speed of the wheel, said anti-skid braking device comprising: a pulsar ring mounted on a rotary member of a wheel, which serves as the inner member, making up a part of the electric generator; a sensor mounted on a wheel support member in face-to-face relation with the pulsar ring and forming another part of the electric generator; the wireless transmitter including a transmitter installed on the wheel support member, and a receiver installed on the automotive body structure, the transmitter transmitting the signal from the sensor by way of a feeble radio wave, the receiver including a demodulating circuit that provides the transmitted signal and a radio field strength signal indicative of the field strength of the transmitted radio wave; and a controller installed on the automotive body structure determining a control of a braking force in dependence on the sensor output signal and the radio field strength signal.