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1. WO2000026631 - METHOD FOR TIRE UNIFORMITY CORRECTION

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[ EN ]

What is claimed is:
1. An improved method for reducing tangential force variation exerted by a pneumatic tire rotating against a load, the improvement comprising:
(a) mounting said tire on a on a known tire uniformity machine having at least two grinding wheels; and
(b) employing said uniformity machine to grind the tire whereby at least one of the grinding wheels is engaging the tire in an up-grinding manner and at least one of the grinding wheels is engaging the tire in a down-grinding manner.
2. The improved invention of Claim 1, wherein:
(a) there are two grinding wheels; and
(b) said grinding wheels are positioned to grind the shoulders of the tread surface of the tire, or opposing intermediate ribs.
3. The improved invention of Claim 2 , wherein unequal grinding pressure is applied to the tire, so that the pressure applied by the grinding wheel engaging the tire in a down-grinding manner is greater than the pressure applied by the grinding wheel engaging the tire in an up-grinding manner.
4. The improved invention of Claim 2, wherein the pressure applied by the grinding wheel engaging the tire in a up-grinding manner corresponds to a load on the grinding wheel motor of about 60 to 80% of the load applied to the motor of the down-grinding wheel. 5. The improved invention of Claim 1, wherein:
(a) there are three grinding wheels; and
(b) two of said grinding wheels are positioned to grind the shoulders of the tread surface of the tire, both of said grinding wheels being driven in the same rotational direction relative to each other; and
(c) the third of said grinding wheels is positioned to grind the center of the tread surface of the tire, said grinding wheel being driven in the opposite rotational direction relative to the grinding wheels positioned on the shoulder of the tire.
6. The improved invention of Claim 5 , wherein unequal grinding pressure is applied to the tire, so that the pressure applied by the center grinding wheel is greater than the pressure applied by the grinding wheels engaging the tire on the shoulders.
7. The improved invention of Claim 5, wherein the pressure applied by the shoulder grinding wheels corresponds to a load on the grinding wheel motors of about 30 to 70% of the load applied to the motor of the center grinding wheels .
8. The improved invention of Claim 1, wherein unequal grinding pressure is applied to the tire, so that the pressure applied by the grinding wheel (s) engaging the tire in a down-grinding manner is greater than the pressure applied by the grinding wheel (s) engaging the tire in an up-grinding manner.
9. The improved invention of Claim 1, wherein the pressure applied by the grinding wheel (s) engaging the tire in a up-grinding manner corresponds to a load on the grinding wheel motor of about 30 to 80% of the load on the grinding wheel motor of the down-grinding wheel (s) .
10. An improved method for simultaneously correcting radial and tangential force variation exerted by a pneumatic tire rotating against a load, regardless of the tire's rotational direction, including the reduction of the tangential force variation component that is resultant from the uniformly sloped tread-blocks of conventional radial force correction, the improvement comprising:
(a) mounting said tire on a tire uniformity machine having two grinding wheels, wherein one grinding wheel is positioned on each shoulder of the tire;
(b) employing said uniformity machine to grind the tire whereby one of the grinding wheels is engaging the tire in an up-grinding manner and the other grinding wheel is engaging the tire in a down-grinding manner; and
(c) applying unequal grinding pressure to the tire, wherein the pressure applied by the grinding wheel engaging the tire in a down-grinding manner is greater that the pressure applied by the grinding wheel engaging the tire in an up-grinding manner.
11. The improved invention of Claim 10, wherein the pressure applied by the grinding wheel engaging the tire in a up-grinding manner corresponds to a load on the grinding wheel motor of about 60 to 80% of the load on the grinding wheel motor of the down-grinding wheel .
12. An improved method for simultaneously correcting radial and tangential force variation exerted by a pneumatic tire rotating against a load, regardless of the tire's rotational direction, including the reduction of the tangential force variation component that is resultant from the uniformly sloped tread-blocks of conventional radial force correction, the improvement comprising:
(a) mounting said tire on a tire uniformity machine having three grinding wheels, wherein a grinding wheel is positioned on each shoulder of the tire, and the remaining grinding wheel is positioned in the center of the tread surface;

(b) employing said uniformity machine to grind the tire whereby at least one of the grinding wheels is engaging the tire in an up-grinding manner and at least one of the grinding wheels is engaging the tire in a down-grinding manner;
(c) driving the grinding wheels positioned on the shoulders of the tire in the same rotational direction relative to each other, and driving the grinding wheel positioned in the center of the tread surface in the opposite rotational direction relative to that of the other grinding wheels; and
(d) applying unequal grinding pressure to the tire, wherein the pressure applied by the center grinding wheels is greater that the pressure applied by the shoulder grinding wheels.
13. The improved invention of Claim 12, wherein the pressure applied by the shoulder grinding wheels corresponds to a load on the grinding wheel motor (s) of about 30 to 70% of the load on the motor of the center grinding wheel .
14. An improved method for reducing tangential force variation exerted by a pneumatic tire rotating against a load, the improvement comprising:
(a) mounting said tire on a on a known tire uniformity machine having two grinding wheels;
(b) grinding the shoulder ribs of said tire whereby the grinding wheels are rotating in the same direction relative to each other, creating a similarly sloped heel-to-toe profile across the tread surface of the tire;
(c) determining the rotational direction of the tire which corresponds to the tread blocks rotating heel-to-toe;
(d) determining on which side of a vehicle said tire should be mounted so that it rotates heel-to-toe when the vehicle moves in the forward direction; and
(e) identifying the tire so that it is to be mounted the specific side of the vehicle, as determined above.
15. A pneumatic tire wherein at least some of the tread blocks on the shoulders of said tire have opposingly sloped heel-to-toe profiles .
16. A pneumatic tire wherein at least some of the tread blocks on the shoulders of said tire have similarly sloped heel-to-toe profiles, and the tread-blocks in the center of the tread surface have a heel-to-toe profile which is of opposite slope relative to that of the shoulder tread blocks .