Method and apparatus for determining the tread depth of a vehicle tire

• US 8,621,919 B2
• Filed: 03/11/2010
• Issued: 01/07/2014
• Est. Priority Date: 04/08/2009
• Status: Active Grant

• Current Assignee: Goodyear Tire & Rubber Company
• Original Assignee: VENTECH GmbH (Goodyear Tire & Rubber Company)
• Inventors: Pingel, Ulrich
• Primary Examiner(s): ALLEN, ANDRE J
• Application Number:
  US13/138,833
• Publication Number:
  US 20120067115A1
• Time in Patent Office: 1,398 Days
• Field of Search: None
• US Class Current: 73/146
• CPC Class Codes: B60C 11/246 Tread wear monitoring systems
• CPC Class Codes: G01B 11/22 for measuring depth

Abstract

A method for determining the tread depth of a vehicle tire, with the tire being mounted on a vehicle, the tire being rolled over or placed on a measuring station, the tread of the tire being optically sensed transversely to the rolling direction of the tire on at least one measuring line, a ray fan extending from a light source being reflected at the tire surface and a signal of the reflected ray fan being recorded by a sensor, and the signal of the reflected ray fan being evaluated by way of a triangulation method, is characterized in that the signal is recorded in a non-orthogonal manner to the tire surface.

Claims

1. A method for determining the tread depth of a vehicle tire, with the tire being mounted on a vehicle, comprising the steps wherein:

while the tire is rolling over a stationary measuring station in a rolling direction, the tread of the tire is optically sensed transversely to the rolling direction of the tire on at least one measuring line, wherein a ray fan extending from a light source being reflected at the tire surface and a signal of the reflected ray fan is recorded by a sensor in a non-orthogonal manner to the tire surface, and wherein measuring is carried out outside a foot print of the tire on the measuring station; and

the signal of the reflected ray fan is evaluated by way of a triangulation method;

wherein a surface angle of the tire is determined as an angle between a normal to the tire surface and the direction towards the light source or the direction towards the sensor.

2. The method of claim 1, wherein the surface angle of the tire is determined by

detecting at two vertically offset positions on the tire surface;

or

by performing several measurements on the tire surface in different distances to the tire;

or

using the diameter of the tire for calculation.

3. The method of claim 1, wherein the ray fan is produced in a light section process.

4. The method of claim 1, wherein the ray fan is produced in a light section process using a laser.

5. The method of claim 1, wherein the ray fan is produced by a line shaped shadowing of at least one spot light source.

6. The method of claim 5, wherein signals of both edges of the line shaped shadowing are evaluated to determine the surface angle of the tire.

11. The method of claim 1, wherein the surface angle of the tire is determined by

detecting at two vertically offset positions on the tire surface;

or

by performing several measurements on the tire surface in different distances to the tire.

7. An apparatus for determining the tread depth of a vehicle tire, with the tire mounted on a vehicle, comprising

a measuring station including a light source and a sensor, wherein the light source produces a ray fan extending along at least one measuring line transversely to the rolling direction of the tire and outside a foot print of the tire wherein the sensor records signals of the ray fan reflected from the tire surface in a non-orthogonal manner with respect to the tire surface;

and

an evaluation unit for the signals of the ray fan reflected from the tire surface which runs through a triangulation method;

wherein the measuring station is further configured to determine a surface angle of the tire as an angle between a normal to the tire surface and the direction towards the light source or the direction towards the sensor by detecting at two vertically offset positions on the tire surface or by performing several measurements on the tire surface in different distances to the tire.

8. The apparatus of claim 7, wherein the light source is comprised of a laser or at least one light emitting diode.

9. The apparatus of claim 7, wherein the sensor is a two dimensionally resolving camera.

10. The apparatus of claim 7, wherein the light source is a light emitting diode and ambient light is eliminated by spectral filters.