Method and device for detecting decompression of tires, and program for judging decompression of tires

A device for detecting decompression of tires based on rotational speed of wheels mounted on a vehicle, comprising:

• a rotational speed-detecting means for determining rotational speeds of said wheels;
• a memory means for memorizing the rotational speeds of said wheels;
• a sensitivity-calculating means for determining loading sensitivity of dynamic load radii of said tires caused by movement of a load during turning of said vehicle;
• a sensitivity-comparing means for comparing the loading sensitivity of dynamic load radii of said tires caused by movement of a load during said turning with predetermined loading sensitivity of dynamic load radii of said tires during normal air pressure;
• and
• a judgment means for judging reduction of air pressure of tires based on a result of said comparison.

A program for judging decompression of tires based on rotational speed of wheels mounted on a vehicle, comprising:

• means for memorizing rotational speeds of said wheels;
• means for determining loading sensitivity of dynamic load radii of said tires caused by movement of a load during turning of said vehicle;
• means for comparing the loading sensitivity of dynamic load radii of said tires caused by movement of a load during said turning with loading sensitivity of dynamic load radii of said tires during normal air pressure;
• and
• means for judging decompression of said tires based on a result of said comparison.

A loading sensitivity-calculating method for determining loading sensitivity of dynamic load radii by loading fluctuation of tires, comprising the steps of:

• determining lateral acceleration of a vehicle during turning of said vehicle;
• determining a shift rate of a judgment value calculated by relative comparison between sums of said wheel rotational speeds on a pair of diagonals of said vehicle during turning of the vehicle;
• and
• determining loading sensitivity obtained by dividing said shift rate by lateral acceleration at every vehicle speed region.

A loading sensitivity-calculating device for determining the loading sensitivity of dynamic load radii by loading fluctuation of tires, comprising:

• a lateral acceleration-calculation means for determining lateral acceleration of a vehicle during turning of said vehicle;
• a shift rate-calculating means for determining a shift rate of a judgment value calculated by relative comparison of sums of said wheel rotational speeds on a pair of diagonals of said vehicle;
• and
• a loading sensitivity-calculating means for determining loading sensitivity obtained by dividing said shift rate by said lateral acceleration at every vehicle speed region.

A program for calculating loading sensitivity of tires comprising:

• means for determining lateral acceleration of a vehicle during turning of said vehicle;
• means for determining a shift rate of a judgment value calculated by relative comparison of sums of said wheel rotational speeds on a pair of diagonals of said vehicle;
• and
• means of determining loading sensitivity obtained by dividing said shift rate by said lateral acceleration at every vehicle speed region.