Abstract: A tire abnormality detecting device has a first unit to be provided on a vehicle body side and a second unit to be provided on a tire side. The first unit includes an electrical signal generating source for generating a specific electrical signal, a first coil device for generating an induction voltage in receipt of the electrical signal, and a device for detecting a change in the induction voltage of the first coil device. The second unit includes a second coil device adapted to be magnetically connected to the first coil device, a third coil device having a magnetic core formed of a temperature sensing magnetic material to form a resonance circuit in cooperation with the second coil device, and a switch mechanism for changing a time constant of the resonance circuit in response to a change in air pressure in a tire. With this construction, the abnormal reduction in air pressure in the tire and/or the abnormal increase in temperature of the tire can be detected.

Abstract: An apparatus for detecting information indicative of the rotation of an engine is disclosed in which a multiplicity of magnetic poles are formed on a track along the circumferential periphery of a rotating member driven by an engine, thus detecting a rotational reference position and a rotational angle from the rotational reference position of the engine. A rotational reference sensor and an angle sensor for generating a signal representing a change in magnetic fluxes by detection of the magnetic fluxes from the track are arranged in opposition to the track in spaced relation from each other along the axis of the rotating member. Some of the magnetic poles on the track which are opposed to the rotational reference sensor are omitted, so that a signal representing the rotational reference position is generated in the case where the angle sensor detects magnetic fluxes but the rotational reference sensor fails to detect the same.