Method for detecting the magnetic field of a tire

• US 6,404,182 B1
• Filed: 06/22/2000
• Issued: 06/11/2002
• Est. Priority Date: 09/27/1996
• Status: Expired due to Term

• Current Assignee: Canon Hi-Tech Limited (Canon Inc.)
• Original Assignee: Canon Hi-Tech Limited (Canon Inc.)
• Inventors: Kawase, Masahiro, Tazaki, Shinichi
• Primary Examiner(s): PATIDAR, JAY M
• Application Number:
  US09/599,418
• Time in Patent Office: 719 Days
• Field of Search: 324/160, 324/163-166, 324/173, 324/174, 324/207.13, 324/207-5-2, 324/207.25, 324/249, 324/260, 735/143.9, 180/170, 340/441, 340/448, 340/466, 340/671, 340/672, 702/142, 702/145, 702/149, 361/143
• US Class Current: 324/173
• CPC Class Codes: G01P 3/481 of pulse signals
• CPC Class Codes: G01P 3/487 delivered by rotating magnets

Abstract

A first portion of a perimeter of an outer circumferential portion of a tire is magnetized with a first polarity along the steel belt in one circumferential direction less than 360° and a second portion of the perimeter is magnetized with a second polarity in an opposite circumferential direction. The magnetic field generated by the magnetized steel belt is detected by two magnetic detection elements, which are set so that the magnetic field detection directions of the two magnetic detection elements are parallel to the side surface of the tire, and the two elements are juxtaposed in a direction perpendicular to the side surface of the tire.

Claims

1. A method for detecting magnetic fields produced by residual magnetization on a steel belt embedded in an outer circumferential portion of a tire, the method comprising:

magnetizing a first portion of said steel belt over a first predetermined angle extending less than 360°

along a first circumferential direction of the tire so that a first magnetic field having a first polarity extends in said first circumferential direction of the tire;

magnetizing a second portion of said steel belt over a second predetermined angle in a second circumferential direction of the tire opposite to said first circumferential direction so that a second magnetic field having a second polarity and opposite to said first polarity extends in said second circumferential direction of the tire;

positioning a first magnetic detection element so that a magnetic field detection direction of said first magnetic detection element is parallel to a side surface of the tire;

positioning a second magnetic detection element so that a magnetic field detection direction of the second magnetic detection element is parallel to the side surface of the tire, wherein said first magnetic detection element and said second magnetic detection element are juxtaposed in a direction perpendicular to the side surface of the tire during detection.

2. The method according to claim 1, wherein one of said first predetermined angle or said second predetermined angle is within a range of about 30°

to 180°

.

3. The method according to claim 1, wherein one of said first predetermined angle or said second predetermined angle is within a range of about 55°

to 105°

.

4. A method for detecting a magnetic field produced by residual magnetization on a steel belt embedded in an outer circumferential portion of a tire, the method comprising:

magnetizing a portion of said steel belt over a predetermined angle range extending less than 360°

along a circumferential direction of the tire,

positioning two magnetic detection elements such that a magnetic field detection direction of each of said two magnetic detection elements are parallel to a side surface of the tire and are juxtaposed in a direction perpendicular to the side surface of the tire during detection.