GB1531967A - Method and system for measuring and correcting vibrations generated in vehicular tyres - Google Patents

Abstract

1531967 Correcting false variations in tyres ONGARO DYNAMICS Ltd 15 March 1977 10863/77 Heading B7C [Also in Division B3] A method of correcting a rubber tyre for vibration producing forces generated in the tyre when operated under load and at cruising speed comprises revolving the tyre at a cruising speed equal to from 50 to 90 m.p.h. under a load simulating the weight load in normal use, measuring the magnitudes and locations of centrifugally generated forces developed in the tyre and comprising (a) forces generated by peripheral non-uniformities and (b) forces developed by lack of tyre symmetry, and correcting the tyre in two stages, the first comprising correction for the (a) forces by removing rubber from the periphery of the tyre in accordance with the magnitude and location of non-uniformities while the tyre is rotating at cruising speed, and the second comprising correction for the (b) forces by selectively adding to or removing rubber from the tyre in the area at or adjacent the tyre beads. In apparatus for carrying out the method, the tyre 17 is mounted on a test wheel and engaged by a road-simulating drum 23 which is urged against the tyre by hydraulic or pneumatic jacks 24, 25 and driven by a drive 21 at the cruising speed. Sensors 26, 27 between the jacks and bearings for the drum detect the forces (a) generated by peripheral non-uniformities, the output from the sensors being fed to a computer 28 which is connected to a controller 30 and drive 31 for a honing device 29 which removes material from the tyre at precise locations to remove the forces generated by the peripheral non-uniformities. At the same time, sensors 34, 35 acting on the bearings for the wheel sense the forces (b) caused by lack of symmetry in the tyre, the output from the sensors being fed to the computer where the signals are recorded and stored. After correction of the tyre for the (a) forces, the tyre is marked and removed from the wheel 16 and is then mounted in the same relative position in a cradle 40 which is oscillated as material is removed from ribs 36, 37 adjacent the beads 38, 39 of the tyre by a honing device 41, 42 controlled by a controller according to the stored signals in the computer whereby the forces (b) caused by lack of tyre symmetry are corrected. Alternatively, strips of rubber may be added to the ribs to correct for the (b) forces.