TG Tire Geometry measurements

All of the TG analyses are based on clearance measurements. These are effeceted by means of capacitive or laser sensors. The RFP-5 Positioning System positions the sensors with respect to the tire. An inspection plan determines the optimal measuring tracks for each tire type. With 3 sensors, as many as 3 tracks can be measured at the same time. All told, up to 9 measuring tracks are managed. During a tire rotation up to 2048 values are recorded per track.

Measuring principle with capacitive measuring sensors

An electrical field - measurable in its intensity and dependent on the clearance between the sensor surface and the tire - forms between the capacitive measur-ing sensor and the tire surface. The sensor's measuring surface is optimized specifically for tire measurements and has an integrating effect. This means that the measurements are affected by all irregularities directly under the measuring surface to the extent of their volume shares. A bulge reduces the distance under the measured surface across the entire surface. The negligible rubber volume of a logo, on the other hand, has only a very minor effect as its volume, distributed over the entire measured surface (= integrated into the overall surface), reduces the clearance only to a very minor extent. This explains why these capacitive distance sensors can also detect bulges under a logo labeling and why, as a con-sequence, no special measuring track is required on the tire. This no longer holds true, however, for large-surface lettering.

Measuring principle of laser measuring sensors

The laser light source creates a light spot at the measuring object. This will be projected onto an opto electronical detector with a defined angle. The position of the projected light spot on the detector changes through the measuring distance between light source and measuring object. An electronical evaluation of the positioning change produces the distance information (triangle procedure). The measurement at tires requires the use of a measuring track that is free of lettering, pins and other contours.

Measuring principle of Sheet-Of-Light sensor

A Sheet-Of-Light sensor consists of a laser and a camera system.

The laser projects a line on the item under test. The camera seizes the deformation of the line with application of the triangulation procedure. Thus an elevator profile can be seized and evaluated.

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