Tire air-pressure alarming device, tire monitored thereby and control method for properties of tire

• US 20050081616A1
• Filed: 09/15/2004
• Published: 04/21/2005
• Est. Priority Date: 09/17/2003
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.), Sumitomo Rubber Industries Limited
• Original Assignee: Advics Company Limited (Aisin Corp.), Sumitomo Rubber Industries Limited
• Inventors: Kajino, Hidenori, Yanase, Minao, Suzuki, Motoshi
• Granted Patent: US 7,233,238 B2
• Time in Patent Office: Days
• US Class Current: 73/146
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00
• CPC Class Codes: Y10T 137/36 With pressure-responsive pressure-control means

Abstract

A tire air-pressure alarming device includes wheel speed sensors for detecting wheel speeds of wheels of a motor vehicle and also includes a microcomputer-base control device and an alarming unit. The control device is programmed to execute function steps of: deriving a decision value based on the wheel speeds detected by the wheel speed sensors; judging the occurrence of air-pressure drop of the tires constituting wheels, based on the decision value; and outputting a command when the occurrence of the air-pressure drop of the tires is judged. The alarming unit is responsive to the command from the control device thereby to raise an alarm indicating the occurrence of the air-pressure drop of the tire. The tires are monitored by the tire air-pressure alarming device, wherein the control device is also programmed to execute a function step of standardizing the speed dependency of a rolling radius of the tires thereby to standardize the performance in judging the air-pressure drop of the tires. Thus, the tire property can be controlled to improve the accuracy in detecting the tire air-pressure drop.

Claims

1. A tire monitored by a tire air-pressure alarming device comprising wheel speed detection means for detecting wheel speeds of wheels of a vehicle;

decision value deriving means for deriving a decision value based on the wheel speeds detected by the wheel speed detection means;

air-pressure drop judging means for judging the occurrence of air-pressure drop of the tires constituting the wheels, based on the decision value derived by the decision value deriving means; and

alarming means for raising an alarm when the occurrence of the air-pressure drop of the tires is judged by the air-pressure drop judging means;

wherein the performance in judging the air-pressure drop of the tires by the air-pressure drop judging means is standardized by standardizing a property value of the tires.

2. The tire as set forth in claim 1, wherein the judging performance is standardized so that the decision value falls within a first predetermined range where the tire air-pressure is a normal pressure, but falls within a second predetermined range where the tire air-pressure is a judgment pressure.

3. The tire as set forth in claim 1, wherein at least one of a rolling radius and a grip property of the tires is utilized as the property value of the tires.

4. The tire as set forth in claim 3, wherein at least one of a friction coefficient to slip rate property, a drive power to slip rate property and a driving stiffness is utilized as the grip property.

5. The tire as set forth in claim 3, wherein the rolling radius of the tire is utilized as the property value of the tires, in which case standardization is set up so that the property value of the tires which is detected in a predetermined state that at least one of vehicle speed, wheel load and air pressure is varied from a reference state falls within a predetermined range.

6. The tire as set forth in claim 3, wherein the grip property of the tire is utilized as the property value of the tires, in which case standardization is set up so that the property value of the tires which is detected in a predetermined state that at least one of vehicle speed, wheel load and air pressure is varied from a reference state, falls within a predetermined range.

7. A control method for a property value of a tire monitored by a tire air-pressure alarming device comprising wheel speed detection means for detecting wheel speeds of wheels of a vehicle;

decision value deriving means for deriving a decision value based on the wheel speeds detected by the wheel speed detection means;

air-pressure drop judging means for judging the occurrence of air-pressure drop of the tires constituting the wheels, based on the decision value derived by the decision value deriving means; and

alarming means for raising an alarm when the occurrence of the air-pressure drop of the tires is judged by the air-pressure drop judging means;

wherein the performance in judging the air-pressure drop of the tires by the air-pressure drop judging means is standardized by standardizing a property value of the tires.

8. The control method as set forth in claim 7, wherein the judging performance is standardized so that the decision value falls within a first predetermined range where the tire air-pressure is a normal pressure, but falls within a second predetermined range where the tire air-pressure is a judgment pressure.

9. The control method as set forth in claim 7, wherein at least one of a rolling radius and a grip property of the tires is utilized as the property value of the tires.

10. The control method as set forth in claim 9, wherein at least one of a friction coefficient to slip rate property, a drive power to slip rate property and a driving stiffness is utilized as the grip property.

11. The control method as set forth in claim 9, wherein the rolling radius of the tires is utilized as the property value of the tires, in which case standardization is set up so that the property value of the tires which is detected in a predetermined state that at least one of vehicle speed, wheel load and air pressure is varied from a reference state of the tires falls within a predetermined range.

12. The control method as set forth in claim 9, wherein the grip property of the tires is utilized as the property value of the tires, in which case standardization is set up so that the property value of the tires which is detected in a predetermined state that at least one of vehicle speed, wheel load and air pressure is varied from a reference state falls within a predetermined range.

13. A tire air-pressure alarming device comprising:

wheel speed detection means for detecting wheel speeds of wheels of a vehicle;

decision value deriving means for deriving a decision value based on the wheel speeds detected by the wheel speed detection means;

air-pressure drop judging means for judging the occurrence of air-pressure drop of the tires constituting the wheels, based on the decision value derived by the decision value deriving means; and

alarming means for raising an alarm when the occurrence of the air-pressure drop of the tires is judged by the air-pressure drop judging means;

wherein the performance in judging the air-pressure drop of the tires by the air-pressure drop judging means is standardized by standardizing a property value of the tires.

14. The tire air-pressure alarming device as set forth in claim 13, wherein the judging performance is standardized so that the decision value falls within a first predetermined range where the air-pressure of the tires is a normal pressure, but falls within a second predetermined range where the air-pressure of the tires is a judgment pressure.

15. The tire air-pressure alarming device as set forth in claim 13, wherein at least one of a rolling radius and a grip property of the tires is utilized as the property value of the tires.