초록 ▼

A tire pressure sensing system for on-board use in an automotive vehicle comprises a transmitter mounted to rotate with each tire and a receiver that is disposed in sensing relationship to each transmitter. Each receiver is a Hall Effect sensor. Each transmitter comprises three magnetic poles that a

A tire pressure sensing system for on-board use in an automotive vehicle comprises a transmitter mounted to rotate with each tire and a receiver that is disposed in sensing relationship to each transmitter. Each receiver is a Hall Effect sensor. Each transmitter comprises three magnetic poles that are effective to cause the Hall Effect sensor to develop a bi-directional pulse waveform during passage of the transmitter past the receiver. Electronic circuitry processes the signal waveform that is created by the Hall Effect sensor in response to passage of the magnetic poles. The circuitry develops one rectangular pulse waveform from one magnetic polarity and another rectangular pulse waveform from the other magnetic polarity. The pressure measurement is insensitive to rotational speed of the tire over a certain range of rotational speeds and the acutal pressure measurement is derived by developing a duty cycle waveform in which the duty cycle is a function of the time interval between the leading edge of one of the rectangular pulse waveforms and the leading edge of the other of the rectangular pulse waveforms. The duty cycle waveform is then integrated and filteted to develop the actual pressure measurement signal.

대표청구항 ▼

A system for providing inflation pressure information from a rotating pneumatic tire comprising three magnetic poles that rotate with the tire, the first of which poles is of one polarity and the second and third of which poles are of the other polarity, means for moving the first and second poles i

A system for providing inflation pressure information from a rotating pneumatic tire comprising three magnetic poles that rotate with the tire, the first of which poles is of one polarity and the second and third of which poles are of the other polarity, means for moving the first and second poles in unison with each other relative to the third pole in accordance with the inflation pressure existing within the pneumatic tire, and sensor means which does not rotate with the tire and which is disposed in sensing relationship to the three magnetic poles as they rotate past the sensor means, said sensor means comprising means to develop from said three magnetic poles a signal waveform that contains information about the inflation pressure of the pneumatic tire irrespective of the particular speed at which the tire is rotating over a given range of rotational speeds for the tire, said signal waveform comprising bi-directional pulses derived from each passage of said three magnetic poles past the sensor means, each bi-directional pulse containing the inflation pressure information.