Patent ID: 7034671
Filing Date: 2006-04-25
Classification: B60C

Abstract:
1. An alarm device for internal pressure of a tire, wherein a transmitting-side module is provided inside of said tire, said transmitting-side module comprising; a sensor unit having at least a pressure sensor for detecting said internal pressure of said tire and tire rotational-movement detecting means for detecting a rotational movement of said tire; a signal-processing unit for processing signals detected at said pressure sensor and said tire rotational-movement detecting means; a transmitting unit for transmitting a tire internal-pressure information signal with a first duration through a transmitting antenna, said tire internal-pressure information signal having a tire internal-pressure data generated in and output from said signal-processing unit based on a detection signal from said pressure sensor; and a power supply for supplying an electric power to said sensor unit, said signal-processing unit and said transmitting unit, and a receiving-side module is provided at a vehicle side, said receiving-side module comprising; a receiving unit for receiving said tire internal-pressure information signal wireless transmitted from said transmitting antenna of said transmitting unit; and a signal-processing unit for processing tire internal-pressure data supplied from said receiving unit and outputting an alarm signal; characterized in that said sensor unit is operated based on a first timing signal with a first interval: (a) if there is no second timing signal with a second interval longer than said first interval: (b) if there is said second timing signal: wherein when a main switch of said vehicle is on, said receiving-side module is always in an operating state, and when said main switch is off, said receiving-side module is operated intermittently at fourth intervals, each fourth interval is shorter than (N−1) times of said third interval, such that a second duration for operation of said receiving-side module is longer than said third interval.