Abstract: A travelling state determination unit of a tire pressure detector determines a travelling state of a vehicle based on a gravitational component force detected by an acceleration sensor. An operation mode switching unit of the tire pressure detector switches the operation mode of the tire pressure detector from a pressure determination mode to an automatic locating mode when the vehicle speed become lower than a threshold value. An interval of period transmission of radio waves in the automatic locating mode is set to be shorter than an interval of the periodic radio wave transmission in the pressure determination mode.

Abstract: Each tire pressure detector detects a characteristic point in a detection signal of an acceleration sensor indicating that the tire pressure detector is located at a certain rotation position. When detecting the characteristic point, the tire pressure detector transmits a notification signal including the detector ID. Whenever a receiver receives a notification signal, the receiver acquires an axle rotation amount of a representative wheel and stores the axle rotation amount in a memory in association with the detector ID in the notification signal. After acquiring axle rotation amounts associated with the detector IDs of all of the tire pressure detectors, the receiver determines mounting positions of tires from the angle each tire pressure detector rotated and the angle each axle rotated between a first determination timing and a second determination timing.

Abstract: Each tire pressure detector detects a characteristic point in a detection signal of an acceleration sensor indicating that the tire pressure detector is located at a certain rotation position. When detecting the characteristic point, the tire pressure detector transmits a notification signal including the detector ID. Whenever a receiver receives a notification signal, the receiver acquires an axle rotation amount of a representative wheel and stores the axle rotation amount in a memory in association with the detector ID in the notification signal. After acquiring axle rotation amounts associated with the detector IDs of all of the tire pressure detectors, the receiver determines mounting positions of tires from the angle each tire pressure detector rotated and the angle each axle rotated between a first determination timing and a second determination timing.

Abstract: A travelling state determination unit of a tire pressure detector determines a travelling state of a vehicle based on a gravitational component force detected by an acceleration sensor. An operation mode switching unit of the tire pressure detector switches the operation mode of the tire pressure detector from a pressure determination mode to an automatic locating mode when the vehicle speed become lower than a threshold value. An interval of period transmission of radio waves in the automatic locating mode is set to be shorter than an interval of the periodic radio wave transmission in the pressure determination mode.

Abstract: A coupling structure for an antenna device including a housing, which retains an antenna element for transmitting or receiving a communication signal, and a wire harness, which extends out of the housing. The coupling structure includes a coupling member that couples the wire harness to a conductor when coupling the housing to a coupling location.

Abstract: A coupling structure for an antenna device including a housing, which retains an antenna element for transmitting or receiving a communication signal, and a wire harness, which extends out of the housing. The coupling structure includes a coupling member that couples the wire harness to a conductor when coupling the housing to a coupling location.