DEVICE FOR MONITORING TIRE AIR PRESSURE

摘要

An air pressure sensor is mounted to a wheel of a vehicle to detect the air pressure of the tire. A wheel-side communication device transmits the detected air pressure of the tire to a vehicle body-side communication device (25) at predetermined intervals. An air pressure memory section (50) stores, as a post-travel air pressure, the air pressure of the tire after the vehicle starts traveling. A comparison section (52) compares the post-travel air pressure with a minimum reference pressure. The minimum reference pressure is the air pressure of the tire immediately after the start of the vehicle or is a predetermined recommended air pressure. When the post-travel air pressure is higher than the minimum reference pressure, a reference pressure setting section (54) sets the post-travel air pressure as a reference pressure for determining the air pressure of the tire. When the post-travel air pressure is equal to or lower than the minimum reference pressure, the reference pressure setting section sets the minimum reference pressure as a reference pressure for determining the air pressure of the tire. An alarm section (56) issues an alarm when the air pressure of the tire is lower than an alarm pressure threshold value determined from the reference pressure.