External Signal supply unit, vehicle state acquisition system and external signal supply method

Abstract

If a trigger signal transmitted from another trigger unit in a set range is received after a transmission command switch has been turned on, an annunciation portion is advised of a likelihood of radio interference. In this case, no trigger signal is supplied. If identifier information that has been received corresponds to the identifier information stored in a memory after the transmission of a trigger signal, a count value remains untouched (YES in S 55 ). It is apparent that identifier information was transmitted before from one of wheel-side units that has supplied a trigger signal, and that the trigger signal has not been received by a desired one of the wheel-side units. An operator can supply a trigger signal again through a change in relative position or the like.

1 . A vehicle state acquisition system comprising:
 a vehicle-body-side unit provided in a vehicle body of a vehicle;   a wheel-side unit that is provided in each of a plurality of wheels of the vehicle and that transmits at least one of wheel state information indicating a state of each of the wheels and identifier information indicating itself; and   an external signal supply unit that supplies a transmission command signal as a signal commanding transmission of the identifier information to the wheel-side unit if at least one of an operation relating to registration of identifier information and an inspection of communication is carried out in the vehicle-body-side unit,   wherein the vehicle-body-side unit acquires a state of each of the wheels by receiving wheel information transmitted from the wheel-side unit, characterized in that the external signal supply unit includes an operation control portion that controls an operation state thereof in accordance with at least one of a state of transmission of identifier information from the at least one wheel-side unit in the set range determined in advance and a state of reception of identifier information by the vehicle-body-side unit.   
     
     
         2 . An external signal supply method that supplies an external signal through radio communication to an on-vehicle unit that is mounted in a vehicle, comprising the step of:
 transmitting the external signal in accordance with a state in a set range that is determined in advance.   
     
     
         3 . The external signal supply method according to  claim 2 , wherein transmission of an external signal is suspended if the existence of an additional external signal supply unit other than an external signal supply unit is detected in the set range. 
     
     
         4 . The external signal supply method according to  claim 2 , wherein an external signal is supplied again to an on-vehicle unit if the external signal was thereby received previously and wherein an external signal is supplied to an additional on-vehicle unit if the external signal was not received by the on-vehicle unit.