Tire information transmitter and tire information acquisition system using the transmitter

Abstract

A tire information transmitter measures ambient information in a tire cavity region including at least pressure to wirelessly transmit to outside the tire cavity region. The tire transmitter comprises: a sensor unit having a pressure sensor for measuring a pressure in the tire cavity region; a control unit for comparing a level of a pressure signal representing pressure measured by the sensor unit with a threshold value and for generating an operation signal indicating that the tire information transmitter is operating; and a transmitting unit for wirelessly transmitting the pressure signal or the operation signal. The control unit controls the transmitting of the transmitting unit and compares the level of the pressure signal with the threshold value continually after a supply of driving power is started, and has a comparing mode in which the transmitting unit transmits the operation signal at a first time interval, and a transmitting mode in which the transmitting unit transmits the pressure signal at a second time interval which is shorter than the first time interval. Further, the control unit irreversibly shifts from the comparing mode to the transmitting mode, once the level of the pressure signal exceeds the threshold value, as a result of the comparing.