System and method for determining tire force

• US 7,506,539 B2
• Filed: 06/29/2007
• Issued: 03/24/2009
• Est. Priority Date: 10/27/2003
• Status: Expired due to Fees

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Tsurita, Tamio, Kunii, Miwa, Miyoshi, Akihiro
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US11/771,714
• Publication Number:
  US 20080011092A1
• Time in Patent Office: 634 Days
• Field of Search: 73146-1468
• US Class Current: 73/146
• CPC Class Codes: G01L 5/164 using variations in inductance

Abstract

A system and method for determining the magnitude of a force acting on a tire are disclosed. Further, a sensor and a tire suitable for use in the system and method are also disclosed. The system comprises: a tire strain sensor mounted on the tire, for detecting a tire strain at the mounted position, and generating data representing tire strain; a sensor locator for locating the sensor on the tire; a memory in which data on the relationship between the tire strain and force acting on the tire at each of measuring points are stored; and a processor computing the magnitude of the force, using the data representing tire strain obtained from the tire strain sensor and the data on the relationship acquired from the memory based on the data on the sensor location obtained from the sensor locator. The method comprises: obtaining data on tire strain from a tire strain sensor mounted on the tire; locating the tire strain sensor, to obtain data on the position of the tire strain sensor; obtaining data on a relationship between the tire strain and the force at the located position of the tire strain sensor, from previously stored data on relationships between the tire strain and force at a plurality of sensor positions; and computing the force using the obtained data on the tire strain and the obtained data on the relationship between the tire strain and the force.

Claims

1. A pneumatic tire comprising

a tread portion,

a pair of sidewall portions,

a pair of bead portions, and

least one strain sensor unit disposed in one of the sidewall portions, each said strain sensor unit is composed of a unitary assembly of at least one magnet and at least one magnetometric sensor element embedded in resilient material so that the magnetometric sensor element is disposed in the magnetic flux of the magnet, and the geometrical arrangement of the magnet and the sensor element is changeable in response to a tire strain so as to cause the sensor element to generate data on the strain at the position in which the strain sensor unit is disposed.

2. The pneumatic tire according to claim 1, wherein said at least one sensor unit is at least three sensor units disposed circumferentially around the tire rotation axis.

3. The pneumatic tire according to claim 1 or 2, wherein the strain sensor unit is composed of a single magnet and a single magnetometric sensor element.

4. The pneumatic tire according to claim 1 or 2, wherein the strain sensor unit is composed of a single magnet and a plurality of magnetometric sensor elements.

5. The pneumatic tire according to claim 1 or 2, wherein the strain sensor is composed of a plurality of magnets and a single magnetometric sensor element.

6. The pneumatic tire according to claim 1 or 2, wherein the strain sensor unit has the most sensitive direction, and the most sensitive direction is inclined at an angle of from 10 to 80 degrees with respect to the tire radial direction.

9. The pneumatic tire according to claim 1, wherein said at least one strain sensor unit is disposed on the inner surface of the sidewall portion.

10. The pneumatic tire according to claim 1, wherein said at least one strain sensor unit is disposed on the outer surface of the sidewall portion.

11. The pneumatic tire according to claim 1, wherein said at least one strain sensor unit is embedded in the sidewall portion.

12. The pneumatic tire according to claim 1, wherein said resilient material is not harder than a tire sidewall rubber to which the strain sensor unit is attached.

13. The pneumatic tire according to claim 1, wherein said resilient material is a sidewall rubber of the tire, whereby said magnet and said magnetometric sensor element are embedded in the sidewall portion, leaving a distance therebetween, and is a hall element.

14. The pneumatic tire according to claim 1, wherein said at least one strain sensor unit is a plurality of strain sensor units disposed within a range between 25% and 75% of the tire sectional height and equiangularly around the tire rotational axis.

15. The pneumatic tire according to claim 1 or 14, wherein lead wires connecting to the strain sensor units are embedded in the tire.

7. A tire strain sensor comprising

at least one magnet, and at least one magnetometric sensor element, which are embedded in a resilient material in one unit so that the magnetometric sensor element is disposed in the magnetic flux of the magnet, and the geometrical arrangement of the magnet and the sensor element is changeable in response to a strain so as to cause the sensor element to generate data on the strain, and wherein

said resilient material is a thermoplastic elastomer.

8. The tire strain sensor according to claim 7, wherein the magnetometric sensor element is a hall element.