# US 2014/0196823 A1 · Tire tread for a farm tractor

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- Number: US 2014/0196823 A1
- Document ID: US20140196823A1
- Status: Published application
- Kind: A1
- Application number: 14/119,465
- Filed: 2012-05-22
- Published: 2014-07-17
- Earliest claimed: 2011-05-25
- Assignees: Michelin Recherche et Tecnique S.A.; Compagnie General Des Establissments Michelin
- Applicants: Michelin Recherche et Technique S.A.; Compagnie Generale Des Etablissements Michelin
- Inventors: Patrick Vervaet; Benoit Buffetaud; Arnaud Larregain
- Web page: https://patentgrep.com/patent/US20140196823A1

## CPC

- B60C 11/0311: {Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation}
- B60C 11/0302: {directional pattern, i.e. with main rolling direction}
- B60C 2011/0313: {directional type}
- B60C 2011/0374: {Slant grooves, i.e. having an angle of about 5 to 35 degrees to the equatorial plane}
- B60C 2200/08: for agricultural vehicles
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES

## Abstract

Tire and tread for a vehicle for agricultural use having reduced attack to leading faces of tread bars, at axially outer ends thereof, by stubble remaining after harvest, thereby reducing risk of chunking of axially outer ends of the bars. The tire and tread has a plurality of bars, a bar having, in any axial plane (Pxy) parallel to the axis of rotation, a leading profile and a trailing profile. The angle (A) of the straight line (T) tangential to the leading profile at a point (M) on the leading profile, with respect to an equatorial plane (P), increases continuously, from an axially outermost point (E) of the leading profile, when the axial distance (L) between the point (M) and the point (E) increases, the angle (A) reaches a maximum value (Am) at a point of inflection (I) of the leading profile, and the radius of curvature (R) at any point (M) , positioned axially between the axially outermost point (E) and the point of inflection (I), is at least equal to 0.4 times the height of the bar.

## Claims

### Claim 1

A tire for a vehicle for agricultural use, comprising:
a tread comprising a plurality of bars,
at least one of said plurality of bars extending radially outwards from a base surface of the tread over a bar height (H), axially towards the inside from an axial end of the tread and circumferentially, in a preferred direction of rotation of the tire, between a leading face and a trailing face,
a bar comprising, in any axial plane (Pxy) parallel to the axis of rotation of the tire, a leading profile, the intersection of the leading face and of the axial plane (Pxy), and a trailing profile, the intersection of the trailing face and of the axial plane (Pxy),
wherein the angle (A) of the straight line (T) tangential to the leading profile at a point (M) on the leading profile, with respect to an equatorial plane (P) of the tire passing through the middle of the tread, increases continuously from an axially outermost point (E) of the leading profile, when the axial distance (L) between the point (M) of the leading profile and the axially outermost point (E) of the leading profile increases, in that the angle (A) reaches a maximum value (Am) at a point of inflection (I) of the leading profile, and in that the radius of curvature (R) at any point (M) on the leading profile, positioned axially between the axially outermost point (E) and the point of inflection (I), is at least equal to 0.4 times the height (H) of the bar.

### Claim 2 (depends on 1)

A tire according to claim 1, wherein the axial distance (L1) between the point of inflection (I) of the leading profile and the equatorial plane (P) of the tire is at least equal to 0.8 times the axial distance (L2) between the axially outermost point (E) of the leading profile and the equatorial plane (P) of the tire.

### Claim 3 (depends on 1)

A tire according to claim 1, wherein the axial distance (L1) between the point of inflection (I) of the leading profile and the equatorial plane (P) of the tire is at most equal to 0.95 times the axial distance (L2) between the axially outermost point (E) of the leading profile and the equatorial plane (P) of the tire.

### Claim 4 (depends on 1)

A tire according to claim 1, wherein the circumferential distance (D1) between the axially outermost point (E) of the leading profile and the trailing profile is at most equal to 0.5 times the distance (D2) between the point of inflection (I) of the leading profile and the trailing profile, measured perpendicular to the trailing profile.

### Claim 5 (depends on 1)

A tire according to claim 1, wherein the angle (A) of the straight line (T) tangential to the leading profile at the axially outermost point (E) of the leading profile, with respect to the equatorial plane (P) of the tire, is at most equal to 5°.

### Claim 6 (depends on 1)

A tire according to claim 1, wherein the angle (A) of the straight line (T) tangential to the leading profile at the point of inflection (I) of the leading profile, with respect to the equatorial plane (P) of the tire, is at least equal to 40°, preferably at least equal to 45°.

### Claim 7 (depends on 1, 2, 3, 4, 5, 6)

A tire according to any one of claims 1 to 6, claim 1, wherein the angle (A) of the straight line (T) tangential to the leading profile at the point of inflection (I) of the leading profile, with respect to the equatorial plane (P) of the tire, is at most equal to 75°, preferably at most equal to 55°.

### Claim 8 (depends on 1)

A tire according to claim 1, wherein the leading face is connected to the base surface by a connection that is continuous and tangential to the base surface.

### Claim 9 (depends on 1)

A tire according to claim 1, wherein the plurality of bars is made up of a first and of a second row of bars which are arranged in a chevron pattern with respect to the equatorial plane (P) of the tire.