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

• US 20050113992A1
• Filed: 11/01/2004
• Published: 05/26/2005
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Kitano, Masashi
• Granted Patent: US 7,551,992 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00
• CPC Class Codes: Y10T 137/3584 Inflatable article [e.g., tire filling chuck and/or stem]
• CPC Class Codes: Y10T 137/36 With pressure-responsive pressure-control means

Abstract

A method for detecting decompression of tires based on the rotational speed of wheels mounted on a vehicle, comprising the steps of: detecting the rotational speed of each of the above-mentioned wheels, determining the speed against ground of the vehicle, calculating the speed information of a fixed wheel from the rotational speeds of said wheels, calculating the judgment value of the wheel position by comparing the speed information of the wheels with the speed against ground of the vehicle, comparing the judgment value of the wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of the wheels at prescribed inner pressure, and judging decompression of tires based on relation between the comparison value of the basis value with the judgment value and a fixed threshold. A region of judging decompression of tires can be broadened and the accuracy of reduced pressure judgment can be improved.

Claims

1. A method for detecting decompression of tires based on the rotational speeds of wheels mounted on a vehicle, comprising the steps of:

detecting the rotational speed of each of said wheels;

determining the speed against ground of said vehicle;

calculating the speed information of a fixed wheel from the rotational speeds of said wheels;

memorizing the rotational speed of each of the wheels and the speed information of said wheels;

calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle;

comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of said vehicle with the speed information of said wheels at prescribed inner pressure; and

judging decompression of tires based on relation between the comparison value of said basis value with the judgment value and a fixed threshold.

2. The method for detecting decompression of tires of claim 1, wherein the speed against ground of said vehicle is determined by signals demodulated from received radio wave of GPS and time.

6. The method for detecting decompression of tires of claim 1, said step of calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle, including the steps of:

determining a relational value between the wheel speeds calculated from the rotational speeds of said wheels and the speed against ground of said vehicle; and

determining a correlation between said relational value and information value related to the vehicle, and said step of comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of said wheels at prescribed inner pressure, including a step of comparing said correlation with said correlation at prescribed inner pressure.

7. The method for detecting decompression of tires of claim 6, wherein the information value related to said vehicle is the sine of gradient of running road surface, the speed against ground of the vehicle, back-and-forth acceleration, lateral acceleration or a turning radius.

8. The method for detecting decompression of tires of claim 6 or 7, wherein the speed against ground of said vehicle is determined by signals demodulated from received radio wave of GPS and time.

9. The method for detecting decompression of tires of claim 1, said step of calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle, including the steps of:

determining the relational value of the wheel speeds calculated from the rotational speeds of the fore-mentioned wheels; and

determining a correlation between said relational value and information value related to the vehicle, and

said step of comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of said wheels at prescribed inner pressure, including a step of comparing said correlation with said correlation at prescribed inner pressure.

10. The method for detecting decompression of tires of claim 9, wherein the relational value of the speeds of said wheels is the correlative value of the speeds of wheels on a pair of diagonals of a vehicle, the ratio of the speed of wheels at a front axle to that at a rear axle, or difference between them, or the ratio of the speed of left front and rear wheels to that of right front and rear wheels, or difference between them.

3. A detection device for detecting decompression of tires based on the rotational speeds of wheels mounted on a vehicle, comprising:

a wheel rotational speed-detecting means for detecting rotational speed of each of said wheels;

a speed against ground of the vehicle-calculating means for determining the speed against ground of the vehicle;

a speed information-calculating means for calculating the speed information of a fixed wheel from the rotational speeds of said wheels;

a memory means for memorizing the rotational speed of each of the wheels and the speed information of said wheels;

a judgment value-calculating means for calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle;

a comparison means for comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of said wheels at prescribed inner pressure; and

a reduced pressure-judging means for judging decompression of tires based on relation between the comparison value of said basis value with the judgment value and a fixed threshold.

4. The method for detecting decompression of tires of claim 3, wherein the speed against ground of said vehicle is determined by signals demodulated from received radio wave of GPS and time.

11. The detection device for detecting decompression of tires of claim 3, said judgment value-calculating means for calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle, including:

a relational value-calculating means for determining a relational value between the speeds of wheels calculated from the rotational speeds of said wheels and the speed against ground of said vehicle; and

a correlation-calculating means for determining a correlation between said relational value and information value related to the vehicle, and

said comparison means for comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of said wheels at prescribed inner pressure, including a comparison means for comparing said correlation with said correlation at prescribed inner pressure.

12. The detection device for detecting decompression of tires of claim 11, wherein the information value related to said vehicle is the sine of gradient of running road surface, the speed against ground of the vehicle, back-and-forth acceleration, lateral acceleration or a turning radius.

13. The detection device for detecting decompression of tires of claim 11 or 12, wherein the speed against ground of said vehicle is determined by signals demodulated from received radio wave of GPS and time.

14. The detection device for detecting decompression of tires of claim 3, said judgment value-calculating means for calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle, including:

a relational value-calculating means for determining the relational value of the speeds of wheels calculated from the rotational speeds of said wheels; and

a correlation-calculating means for determining a correlation between said relational value and information value related to the vehicle, and

said comparison means for comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of said wheels at prescribed inner pressure, including a comparison means for comparing said correlation with said correlation at prescribed inner pressure.

15. The detection device for detecting decompression of tires of claim 14, wherein the relational value of the speeds of said wheels is the correlative value of the speeds of wheels on a pair of diagonals of a vehicle, the ratio of the speed of wheels at a front axle to that at a rear axle, or difference between them, or the ratio of the speed of left front and rear wheels to that of right front and rear wheels, or difference between them.

5. A program for judging decompression of tires based on the rotational speeds of wheels mounted on a vehicle, comprising:

a speed information-calculating means for calculating the speed information of a fixed wheel from the rotational speeds of said wheel;

a memory means for memorizing the rotational speed of each of the wheels and the speed information of said wheels;

a judgment value-calculating means for calculating the judgment value of said wheel position by comparing the speed information of said wheels with the speed against ground of the vehicle;

a comparison means for comparing the judgment value of said wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of said wheels at prescribed inner pressure; and

a reduced pressure-judging means for judging decompression of tires based on relation between the comparison value of said basis value with the judgment value and a fixed threshold.

16. The program for judging decompression of tires of claim 5, further comprising:

said judgment value-calculating means including;

a relational value-calculating means for determining the relational value of the speeds of wheels calculated from the rotational speeds of said wheels and the speed against ground of the vehicle determined; and

a correlation-calculating means for determining a correlation between said relational value and information value related to the vehicle, and

said comparison means including a comparison means for comparing said correlation with said correlation at prescribed inner pressure.

17. The program for judging decompression of tires of claim 16, wherein the information value related to said vehicle is the sine of gradient of running road surface, the speed against ground of the vehicle, back-and-forth acceleration, lateral acceleration or a turning radius.

18. The program for judging decompression of tires of claim 5, further comprising:

said judgment value-calculating means including;

,

a relational value-calculating means for determining the relational value of the speeds of wheels calculated from the rotational speeds of said wheels; and

a correlation-calculating means for determining a correlation between said relational value and the information value related to the vehicle, and

said comparison means including a comparison means for comparing said correlation with said correlation at prescribed inner pressure.

19. The program for judging decompression of tires of claim 18, wherein the relational value of the speeds of said wheels is the correlative value of the speeds of wheels on a pair of diagonals of a vehicle, the ratio of the speed of wheels at a front axle to that at a rear axle, or difference between them, or the ratio of the speed of left front and rear wheels to that of right front and rear wheels, or difference between them.