Method of correcting variations in radial force between a tire and the ground
First Claim
1. A method of correcting defects in uniformity of a tire mounted on a rim the rim flanges of which have a portion perpendicular to the axis of rotation, which includes rolling the tire mounted , inflated and under load on the drum of a uniformity machine, graphically recording the variation in radial force of the rolling assembly consisting of tire and rim, and removing the tire from its rim, characterized by the fact that:
- the variation in radial force (FR) is broken down into its harmonics of the 1st to 16th order;
the variations in the harmonics are checked with respect to control limits which are not to be exceeded;
a variation of radial force (FRn) which takes into account the harmonic of the highest order which it is necessary to correct and all harmonics of lower order is recomposed;
the amplitude of the variation (FRn) thus obtained is determined as well as the circumferential positions of the optimums (maximum FM and minimum Fm) of this variation (FRn); and
by placing, between the vertical walls (23) of the rim flanges (20) and the corresponding walls of the beads (12) on each side of the tire (1), a compensation wedge (30) in the form of a circular ring, the outside radius (R1) of which is at least equal to the radius (RT) of the point of tangency (T) between the upper rounded portion (24) and the vertical wall (23) of the flange of the rim (20), the inner radius (R2) of which is at most equal to the radius (RS) of the point of tangency (S) between the vertical wall (23) and the lower rounded portion (22) of the flange of the rim and the thickness (e) of which is constant radially over the height (H), and variable circumferentially between a maximum value (eM) at the level of the maximum value (FM) of the variation in radial force (FRn) and substantially proportional to the amplitude (A) of the variation (FRn) and a minimum value (em) of 0.3 mm at the level of the minimum value (Fm) of the variation (FRn), the value of the thickness (e) between these two extremes (eM) and (em) for the point of the wedge (30) corresponding to the value (F) of the radial force measured being such that the quantity e-0.3 in mm is proportional to the quantity F-Fm, the compensation wedge being made of a plastic or elastomeric simple or composite material of a density of at most 1.2.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of correcting the variations of radial force between a tire and the ground, including measuring on a uniformity machine the variation in radial force of the tire/mounting-rim rolling assembly, reconstituting a radial variation on basis of the harmonic variations to be corrected, and effecting said correction by means of wedges in the form of circular rings placed between the mounting rim and the beads of the tire.
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Citations
10 Claims
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1. A method of correcting defects in uniformity of a tire mounted on a rim the rim flanges of which have a portion perpendicular to the axis of rotation, which includes rolling the tire mounted , inflated and under load on the drum of a uniformity machine, graphically recording the variation in radial force of the rolling assembly consisting of tire and rim, and removing the tire from its rim, characterized by the fact that:
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the variation in radial force (FR) is broken down into its harmonics of the 1st to 16th order; the variations in the harmonics are checked with respect to control limits which are not to be exceeded; a variation of radial force (FRn) which takes into account the harmonic of the highest order which it is necessary to correct and all harmonics of lower order is recomposed; the amplitude of the variation (FRn) thus obtained is determined as well as the circumferential positions of the optimums (maximum FM and minimum Fm) of this variation (FRn); and by placing, between the vertical walls (23) of the rim flanges (20) and the corresponding walls of the beads (12) on each side of the tire (1), a compensation wedge (30) in the form of a circular ring, the outside radius (R1) of which is at least equal to the radius (RT) of the point of tangency (T) between the upper rounded portion (24) and the vertical wall (23) of the flange of the rim (20), the inner radius (R2) of which is at most equal to the radius (RS) of the point of tangency (S) between the vertical wall (23) and the lower rounded portion (22) of the flange of the rim and the thickness (e) of which is constant radially over the height (H), and variable circumferentially between a maximum value (eM) at the level of the maximum value (FM) of the variation in radial force (FRn) and substantially proportional to the amplitude (A) of the variation (FRn) and a minimum value (em) of 0.3 mm at the level of the minimum value (Fm) of the variation (FRn), the value of the thickness (e) between these two extremes (eM) and (em) for the point of the wedge (30) corresponding to the value (F) of the radial force measured being such that the quantity e-0.3 in mm is proportional to the quantity F-Fm, the compensation wedge being made of a plastic or elastomeric simple or composite material of a density of at most 1.2. - View Dependent Claims (2, 3, 4, 6, 7)
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5. A method of correcting defects in uniformity of a tire mounted on a rim, the seats of which form an angle of 15°
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1°
with the axis of rotation of the tire, including measuring the amplitude and the circumferential positions of the optimums of the variation in radial force of the first harmonic by rolling on a uniformity machine, characterized by the fact that after measurements and demounting of the tire, there is placed between the seats (21) of the rim (20) and the seats of beads (12) of the tire (1) on each side of the tire (1), a compensation wedge (30) having a cross section in the shape of a parallelogram, the width (1c) of which is at least equal to 80% of the width (1) of the bead (12), the thickness (e) of which, measured perpendicular to the seats (21) of the rim (20), is constant over a cross section but variable circumferentially between a value (eM) which is maximum at the level of the minimum value (Fm) of the radial force FR1) and a minimum value (em) of 0.3 mm at the level of the maximum value (FM), the value (eM) being proportional to the amplitude (A1) of the variation (FR1), the value of the thickness (e) at a point of the wedge corresponding to the radial force (F) being such that e-0.3 mm is proportional to F-Fm, the compensation wedge being made of a plastic or elastomeric simple or composite material of a density of at most 1.2.
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- 8. A method of making an annular compensation wedge ring for correcting the defects in the uniformity of a tire by being placed between vertical portions of the mounting rim and the beads of the tire comprising the steps of determining the variation in radial force of the inflated tire under load over a complete revolution and forming the annular compensation wedge ring of a plastic or elastomeric material having a density of at most 1.2 and a thickness which is at least 0.3 mm, the wedge being of constant thickness radially over its height and of variable thickness circumferentially, the circumferential variation in thickness varying from a minimum thickness value at the location of minimum radial force to a maximum thickness at the location of maximum radial force, the variation in thickness having the same direction as the variation in radial force.
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10. A method of making an annular compensation wedge ring for correcting defects in uniformity of a tire by being placed between the beads of a tire and the seats of a rim which form an angle of 15°
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1°
with the axis of rotation of the tire comprising determining the amplitude and the circumferential positions of the optimums of the variation in radial force of the first harmonic of the inflated tire under load over a complete revolution and forming the annular compensation wedge ring of plastic or elastomeric material having a density of at most 1.2 and a thickness which is at least 0.3 mm, the thickness of the wedge ring, measured perpendicular to the seat of the rim, being constant axially over its length but variable circumferentially between a maximum value at the location of the minimum value of the radial force and a minimum value at the location of the maximum value of the radial force, the variation in thickness varying inversely as the variation in radial force between minimum and maximum.
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Specification