Tread for the tire of a farm tractor

Patent metadata

Field	Value
Publication number	US-10239357-B2
Application number	US-201213978079-A
Country	US
Kind code	B2
Filing date	Jan 4, 2012
Priority date	Jan 6, 2011
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A tread and tire for a multipurpose agricultural machine, that improves field traction while ensuring a satisfactory compromise with wear under engine torque and vibratory comfort on the road having a tread having a plurality of lugs distributed in a first row extending axially from a first axial end of the tread and in a second row extending axially from a second axial end of the tread, the second row differing from the first row by a symmetry relative to the equatorial plane of the tire followed by a rotation about the rotation axis of the tire, each row having an alternation of long lugs and of short lugs. The axially inner end face of a first long lug of a row of lugs is separated from the trailing lateral face of the second long lug of the symmetrical row of lugs, closest to the axially inner end face of the first long lug, by an end groove with a width at least equal to 10% and at most equal to 100% of the lug height.

First claim

The invention claimed is:

1. A tire for a multipurpose agricultural machine, comprising:
a tread designed to come into contact with the ground via a tread surface having two axial ends, the axial distance between the axial ends being the width of the tread (L),
the tread comprising a plurality of lugs extending radially between an inner surface of revolution about the rotation axis of the tire and the tread surface, the radial distance between the said surfaces being the lug height (H),
each lug comprising a leading lateral face, a trailing lateral face, an axially outer end face, an axially inner end face and a contact face,
the plurality of lugs being distributed in a first row of lugs extending axially from a first axial end of the tread and a second row of lugs extending axially from a second axial end of the tread, the second row of lugs being identical to the first row of lugs and placed as a mirror image of the first row of lugs that is offset in the circumferential direction of the tire,
each row of lugs consisting of an alternation of long lugs, of which an axial distance (L 1 ) between the respectively axially outer and inner end faces is at least equal to half the width of the tread (L), and of short lugs, of which an axial distance (L 2 ) between the respectively axially outer and inner end faces is at most equal to half the width of the tread (L),
wherein the axially inner end faces of a plurality of first long lugs of the first row of lugs are separated from the trailing lateral faces of a plurality of second long lugs of the second row of lugs, closest to the axially inner end faces of the plurality of first long lugs, by an end groove with a width (e) at least equal to 10% and at most equal to 100% of the lug height (H), and
wherein the end groove between the axially inner end face of at least one first long lug of the plurality of first long lugs and the trailing lateral face of at least one second long lug of the plurality of second long lugs, closest to the axially inner end face of the at least one first long lug, includes an elastomeric linking element extending radially outwards from the inner surface of the tread between the axially inner end face of the at least one first long lug and the trailing lateral face of the at least one second long lug having a radial height (h),
wherein the entire elastomeric linking element is spaced from the equatorial plane,
wherein each of the first and second long lugs connecting to an elastomeric linking element comprises at least one inner groove between its respectively axially outer end face and inner end face.

2. The tire according to claim 1 , wherein the end groove between the axially inner end face of at least one first long lug and the trailing lateral face of at least one second long lug, closest to the axially inner end face of the at least one first long lug, extends radially between the inner surface of revolution about the rotation axis of the tire and the tread surface of the tread.

3. The tire according to claim 1 , wherein the radial height (h) of the elastomeric linking element is at most equal to 75% of the lug height (H).

4. The tire according to claim 1 , wherein the axial distance (L 1 ) between the respectively axially outer end face and inner end face of each long lug is at most equal to 70% of the tread width (L).

5. The tire according to claim 1 , wherein the axial distance (L 2 ) between the respectively axially outer end face and inner end face of each short lug is at least equal to 20% of the tread width (L).

6. The tire according to claim 1 , wherein the axial distance (L 2 ) between the respectively axially outer end face and inner end face of each short lug is at most equal to 40% of the tread width (L).

7. The tire according to claim 1 , wherein an angle of inclination (a) of a tangent (t e ) to a centre line (m) of the contact face of each lug at an axially outer end point (E) of the said centre line, relative to the circumferential direction (X), is at least equal to 45° and at most equal to 90°.

8. The tire according to claim 7 , wherein the angle of inclination (a) is at least equal to 50° and at most equal to 75°.

9. The tire according to claim 1 , wherein an angle of inclination (b) of a tangent (t 1 ) to a centre line (m) of the contact face of each long lug at an axially inner end point (I) of the said centre line, relative to the circumferential direction (X), is at least equal to 15° and at most equal to 45°.

10. The tire according to claim 9 , wherein the angle of inclination (b) is at least equal to 25° and at most equal to 35°.

11. The tire according to claim 1 , wherein an average angle of inclination (c) of a straight line (D) passing through the respectively axially outer end point (E) and inner end point (I) of a centre line (m) of the contact face of each long lug, relative to the circumferential direction (X), is at least equal to 40° and at most equal to 60°.

12. The tire according to claim 1 , wherein the at least one inner groove has a width (e 1 ) at most equal to 100% of the lug height (H).

13. The tire according to claim 1 , wherein a radial depth (p) of the at least one inner groove is at least equal to 25% of the lug height (H).

14. The tire according to claim 1 , wherein each long lug comprises only one inner groove between its respectively axially outer end face and inner end face.

15. The tire according to claim 14 , wherein the inner groove of each long lug is disposed at an equal axial distance to the equatorial plane as the axially inner end face of a short lug of the same row of lugs.

16. The tire according to claim 1 , wherein a distance in the contact face of each lug measured between the leading lateral face and the trailing lateral face is constant along the entire length of each respective lug.

17. The tire according to claim 16 , wherein each elastomeric linking element extends at a distance from the leading lateral face to the trailing lateral face of the at least one first long lug in the plurality of first long lugs that remains constant along the entire width (e) of each respective end groove.

Assignees

• Vervaet Patrick
• Royer Thierry
• Michelin & Cie
• Michelin Rech Tech

Inventors

• Vervaet Patrick
• Royer Thierry

Classifications

• B60C2011/0313

  directional type · CPC title

• B60C11/0311 Primary

  Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation · CPC title

• B60C11/033 Primary

  by the void or net-to-gross ratios of the patterns · CPC title

• B60C2200/08

  for agricultural vehicles · CPC title

• B60C11/1369

  Tie bars for linking block elements and bridging the groove · CPC title