Tire information transmitter and tire information acquisiton system using the transmitter

A tire information acquisition system comprising:

• a tire information transmitter which is mounted to a tire cavity region surrounded by an inner peripheral surface of a tire and a wall surface of a wheel, and measures ambient information in the tire cavity region including at least pressure to wirelessly transmit to outside the tire cavity region, and a receiver which is mounted outside of the tire cavity region surrounded by the inner peripheral surface of the tire and the wall surface of the wheel, and receives a pressure signal from the tire information transmitter,
• the tire information transmitter comprising:
• 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;
• wherein,
• 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, and once the level of the pressure signal exceeds the threshold value, as a result of the comparing, the control unit irreversibly shifts from the comparing mode to the transmitting mode.