TIRE WITH ONE OR MORE RECESSES IN THE LATERAL GROOVES OF AT LEAST ONE SHOULDER PORTION

Abstract

This invention relates to a tire, such as a pneumatic all-seasons tire, comprising a tread portion extending in a tire width direction and that is divided between an outer shoulder portion, a central portion and an inner shoulder portion; each of the outer shoulder portion and the inner shoulder portion comprises lateral grooves having an internal end and an external end; wherein at least one of the outer shoulder portion and the inner shoulder portion has at least one lateral groove comprising one or more recesses, wherein the cumulated length of the recesses in the lateral groove ranges from 20% to 60% of the total lateral groove length in the footprint, and wherein one or more recesses are placed at a distance from the internal end of the lateral groove.

Claims

1. A tire comprising a tread portion which is divided in the tire width direction between an outer shoulder portion, a central portion and an inner shoulder portion; wherein an outside main circumferential groove extending in the circumferential direction of the tire is disposed between the outer shoulder portion and the central portion, and an inside main circumferential groove extending in the circumferential direction of the tire is disposed between the central portion and the inner shoulder portion; each of the outer shoulder portion and the inner shoulder portion comprises lateral grooves having two ends in the footprint said ends including an internal end and an external end; wherein at least one of the outer shoulder portion and the inner shoulder portion has at least one lateral groove comprising one or more recesses, wherein the cumulated length of the one or more recesses in the lateral groove ranges from 20% to 60% of the total lateral groove length in the footprint; and further wherein one or more recesses are placed at a distance from the internal end of the lateral groove; the footprint of the tire being obtained according to ASTM F870-94: 2016.

2. The tire according to claim 1, wherein the depth of the one or more recesses ranges from 120% to 180% of the depth of the lateral groove.

3. The tire according to claim 1, wherein the one or more recesses are placed at a distance from the internal end of the lateral groove which is within the range of 10% to 35% of the total lateral groove length in the footprint.

4. The tire according to claim 1, wherein at least one lateral groove of the outer shoulder portion has an extension extending from its internal end to the outside main circumferential groove and/or at least one lateral groove of the inner shoulder portion has an extension extending from its internal end to the inside main circumferential groove.

5. The tire according to claim 4, wherein the extension of the lateral groove of the outer shoulder portion and/or of the lateral groove of the inner shoulder portion has a depth similar or superior to the depth of the lateral groove from which it extends.

6. The tire according to claim 1, wherein the outer shoulder portion and/or the inner shoulder portion comprises a narrow groove extending in the circumferential direction of the tire that is crossing the lateral grooves in a part that is extending from the internal end of the lateral groove to a recess.

7. The tire according to claim 6, wherein the narrow circumferential groove has the same depth than the lateral groove.

8. The tire according to claim 1, wherein the depth of the lateral grooves comprising one or more recesses of the outer shoulder portion is ranging from 60% to 85% of the depth of the outside main circumferential groove and/or the depth of the lateral grooves comprising one or more recesses of the inner shoulder portion range from 60% to 85% of the depth of the inside main circumferential groove.

9. The tire according to claim 1, wherein at least one of the outer shoulder portion and the inner shoulder portion has at least one lateral groove comprising a single recess.

10. A tire comprising a tread portion which is divided in the tire width direction between an outer shoulder portion, a central portion and an inner shoulder portion; wherein an outside main circumferential groove extending in the circumferential direction of the tire is disposed between the outer shoulder portion and the central portion, and an inside main circumferential groove extending in the circumferential direction of the tire is disposed between the central portion and the inner shoulder portion; each of the outer shoulder portion and the inner shoulder portion comprises lateral grooves having two ends in the footprint said ends including an internal end and an external end; wherein at least one of the outer shoulder portion and the inner shoulder portion has at least one lateral groove comprising one or more recesses, wherein the depth of the one or more recesses ranges from 120% to 180% of the depth of the lateral groove; wherein the cumulated length of the one or more recesses in the lateral groove is at least 20% of the total lateral groove length in the footprint; and further wherein the one or more recesses are placed at a distance from the internal end of the lateral groove; wherein the footprint of the tire is obtained according to ASTM F870-94: 2016.

11. The tire according to claim 10, wherein the one or more recesses are placed at a distance from the internal end of the lateral groove that is at least 10% of the total lateral groove length in the footprint.

12. The tire according to claim 10, wherein the one or more recesses have a constant depth along their length.

13. The tire according to claim 10, wherein at least one lateral groove of the outer shoulder portion shows an extension extending from its internal end to the outside main circumferential groove and/or in at least one lateral groove of the inner shoulder portion shows an extension extending from its internal end to the inside main circumferential groove wherein the extension has a width smaller than the width of the lateral groove.

14. The tire according to claim 13, wherein the extension of the lateral groove of the outer shoulder portion and/or of the lateral groove of the inner shoulder portion has a depth similar or superior to the depth of the lateral groove from which it extends.

15. The tire according to claim 10, wherein apart from the one or more recesses, the lateral grooves have a constant depth along their length.

16. The tire according to claim 10, wherein both the outer shoulder portion and the inner shoulder portion have at least one lateral groove comprising one or more recesses.

17. A tire comprising a tread portion which is divided in the tire width direction between an outer shoulder portion, a central portion and an inner shoulder portion; wherein an outside main circumferential groove extending in the circumferential direction of the tire is disposed between the outer shoulder portion and the central portion, and an inside main circumferential groove extending in the circumferential direction of the tire is disposed between the central portion and the inner shoulder portion; each of the outer shoulder portion and the inner shoulder portion comprises lateral grooves having two ends in the footprint said ends including an internal end and an external end; wherein at least one of the outer shoulder portion and the inner shoulder portion has at least one lateral groove comprising one or more recesses, wherein the one or more recesses are placed at a distance from the internal end of the lateral groove that is at least 10% of the total lateral groove length in the footprint and further wherein the cumulated length of the one or more recesses in the lateral groove is at least 20% of the total lateral groove length in the footprint; the footprint of the tire being obtained according to ASTM F870-94: 2016.

18. The tire according to claim 17, wherein the one or more recesses are placed at a distance from both the internal end and the external end of the lateral groove so that the one or more recesses are closed in the footprint, wherein the depth of the one or more recesses ranges from 130% to 170% of the depth of the lateral groove.

19. The tire according to claim 6, wherein the narrow circumferential groove has a depth of at least 110% of the depth of the lateral groove.

20. The tire according to claim 10, wherein the one or more recesses are placed at a distance from the internal end of the lateral groove that is at least 20% of the total lateral groove length in the footprint.

Description

DESCRIPTION OF THE DRAWINGS

[0059] FIG. 1 is a plan view of a tire with a tread according to the disclosure.

[0060] FIG. 2 is an enlarged partial view of a tread portion of the tire of FIG. 1.

[0061] FIG. 3 is an enlarged elevated view of a portion of the outer shoulder portion of the tire of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0062] In the below description the footprint is obtained according to ASTM F870-94: 2016. Reference is made to FIG. 1 that illustrates a tire 1 according to the present disclosure, and FIG. 2 that is a partial view of the tread portion of the tire 1. Indeed, the tire 1 includes a tread portion extending in a tire width direction, a pair of sidewall portions (not shown) extending inward in a tire radial direction from both ends of the tread portion and a pair of bead portions (not shown) each provided at an inner end of a corresponding one of the pair of sidewall portions in the tire radial direction. In the tread portion, a plurality of ribs is formed by a plurality of main circumferential grooves (i.e. extending in the tire circumferential direction). The tire can be a pneumatic tire or a non-pneumatic tire; with preference, the tire is a pneumatic tire.

[0063] For example, the tire is an all-season tire or a winter tire; with preference an all-season tire. For example, the tire is an all-season pneumatic tire or a winter pneumatic tire; with preference an all-season pneumatic tire. For example, the tire is an all-season tire or a winter tire and shows a “three-peak mountain snowflake” symbol (i.e. “3PMSF” symbol).

[0064] The tread pattern of the tire can be symmetric or asymmetric. For example, the tire has an asymmetric tread.

[0065] The tire includes from 2 to 4 main grooves extending in the tire circumferential direction arranged from an outside (i.e. the right side in FIG. 1) to an outside (i.e. the left side in FIG. 1). The distinction between outside and inside side of the tire is relevant in the embodiment wherein the tire has an asymmetric tread pattern. In such a case, the tires show marks to differentiate the two sides so that the side marked “outside” is towards the outside of the vehicle and the “inside” side towards the inside when the tire is mounted on the vehicle. Persons skilled in the art will adapt the below description without any difficulty to the embodiment wherein the tread pattern of the tire is symmetric, with the outer shoulder portion being symmetrical to the inner shoulder portion the equatorial plane of the tire. Tire with symmetric tread pattern are devoid of marks to differentiate the two sides. On FIGS. 1 and 2, the tire comprises 4 main grooves (3, 5, 7, 9) extending in the tire circumferential direction. The main circumferential grooves are depressed inward in the tire radial direction.

[0066] An outside main circumferential groove 3 is provided on the outside. The outermost region in the tire tread width direction defined by the outside main circumferential groove 3 and the outside lateral edge is the outer shoulder portion 11 (or outside rib). The outside main circumferential groove 3 can be straight (as illustrated in FIG. 1) or can extend in a zig-zag shape in the tire circumferential direction (not shown). In the latter configuration, when the outside main circumferential groove is extending in a zig-zag shape in the tire circumferential direction; the outside main circumferential groove includes a first inclined portion extending in the tire circumferential direction and obliquely outward from the tire tread width direction, and a second inclined portion extending in the tire tread width direction.

[0067] An inside main circumferential groove 9 is provided on the inside. The innermost region in the tire tread width direction defined by the inside main circumferential groove and the inside lateral edge is the inner shoulder portion 15 (or inside rib). The inside main circumferential groove 9 extends on the same circumference in the tire circumferential direction. The inside circumferential main groove 9 can be straight or in a zig-zag shape. In an embodiment, the inside main circumferential groove 9 is a straight groove extending in the circumferential direction.

[0068] The portion disposed between the outside main circumferential groove 3 and the inside main circumferential groove 9 forms the central portion 13 of the tire 1. The central portion 13 may be devoid of a main circumferential groove; however, it is preferred that one or two main central circumferential grooves (5, 7) are placed in the central portion 13 of the tire. In an embodiment (not shown) a single main groove is extending in the circumferential direction, the single main circumferential groove can be straight or can extend in a zig-zag shape. The single main circumferential groove is preferably disposed at the centre in the width direction of the tire. I n the embodiment illustrated in FIGS. 1 and 2, the central portion 13 comprises two main grooves (5, 7) extending in the circumferential direction and defining 3 central ribs with the outside main circumferential groove and the inside main circumferential groove. The central main circumferential grooves (5, 7) can be straight or in a zig-zag shape. In an embodiment, the central main circumferential grooves (5, 7) are straight.

[0069] The outer shoulder portion 11, the central portion 13 and the inner shoulder portion 15 comprise each a plurality of lateral grooves (17, 19, 21) that extends in the width direction of the tire 1. The first lateral grooves 17 are formed in the outer shoulder portion 11. The second lateral grooves 19 are formed in the central portion 13. The third lateral grooves 21 are formed in the inner shoulder portion 15. The lateral grooves (17, 19, 21) are all depressed inward in the tire radial direction and all extend obliquely in the tire tread width direction. In an embodiment not shown the lateral grooves of the outer shoulder portion and/or of the inner shoulder portion extend in an axial direction. Each lateral groove (17, 19, 21) is showing two ends in the footprint. In particular, each of the outer shoulder portion 11 and the inner shoulder portion 15 comprises lateral grooves (17, 21) having two ends in the footprint. With regard to the lateral grooves (17, 21) of the outer and inner shoulder portion (11, 15), the end that is closer to the central portion 13 of the tire 1 is the internal end and the end further from the central portion 13 of the tire 1 is the external end. The lateral grooves (17, 21) of the outer and inner shoulder portion (11, 15) remain open in the footprint by their external end on their respective lateral edge. The lateral grooves (17, 21) of the outer and inner shoulder portion (11, 15) can be straight or curved, they are preferably straight.

[0070] The outer shoulder portion 11 is described with reference to FIG. 3. The description of the outer shoulder portion 11 can be adapted by the person skilled in the art by analogy to the inner shoulder portion 15. The outer shoulder portion 11 (or the inner shoulder portion 15) shows a plurality of lateral grooves 17 (referenced 21 in the inner shoulder portion 15) that extend obliquely outward in the tire tread width direction and the same tire circumferential direction. The plurality of lateral grooves 17 defines with the outside main circumferential groove 3 a plurality of blocks 23 (referenced 25 in the inner shoulder portion 15).

[0071] According to the disclosure, at least one of the lateral grooves 17 of the outer shoulder portion 11 and/or the lateral grooves 21 of the inner shoulder portion 15 show one or more recesses 27 extending along the length of the lateral grooves (17, 21). The one or more recesses 27 are formed in the bottom of the lateral grooves (17, 21).

[0072] For example, at least 30% of the lateral grooves 17 of the outer shoulder portion 11 and/or the lateral grooves 21 of the inner shoulder portion 15 show one or more recesses 27; preferably at least 50%, preferably at least 80%, the remaining lateral grooves being devoid of a recess. In an embodiment, all the lateral grooves 17 of the outer shoulder portion 11 and/or the lateral grooves 21 of the inner shoulder portion 15 show one or more recesses 27.

[0073] It is preferred that the lateral grooves comprising one or more recesses of the outer shoulder portion and/or of the inner shoulder portion have a depth that is reduced by comparison to lateral grooves devoid of a recess when present in the tire. Thus, in an embodiment wherein the outer shoulder portion and/or the inner shoulder portion comprise lateral grooves devoid of a recess; the depth of the lateral grooves devoid of a recess is ranging from 120% to 180% of the depth of the lateral groove comprising one or more recesses; preferably, from 130% to 170%; more preferably, from 140% to 160%; even more preferably, from 145% to 155%. For example, the depth of the one or more recesses in the lateral groove of the outer shoulder portion and/or of the inner shoulder portion is the same than the depth of the lateral grooves devoid of a recess.

[0074] In one embodiment of this invention, both the outer shoulder portion 11 and the inner shoulder portion 15 have at least one lateral groove (17, 21) comprising one or more recesses 27. In an embodiment, both the outer shoulder portion 11 and the inner shoulder portion 15 have all the lateral grooves (17, 21) comprising one or more recesses 27. In an embodiment, both the outer shoulder portion 11 and the inner shoulder portion 15 have all lateral grooves (17, 21) comprising one single recess 27. In an embodiment, apart from the one or more recesses 27, the lateral grooves (17, 21) have a constant depth along their length.

[0075] Each recess 27 extends onto a part of the total length the lateral groove (17, 21) with the depth of the recess 27 being superior to the depth of the lateral groove (17, 21).

[0076] In an embodiment not illustrated, one or more of the lateral grooves comprise a plurality of recesses. For example, one or more lateral grooves may comprise 2 to 4 recesses distributed along the length of the lateral grooves. In the embodiment depicted in FIGS. 1 and 2, the lateral grooves (17, 21) comprise a single recess 27. It is possible to mix lateral grooves having a plurality of recesses with lateral grooves having a single recess on the same tire. For example, the inner shoulder portion may show lateral grooves having a plurality of recesses whereas the outer shoulder portion shows lateral grooves having a single recess or vice-versa. It is also possible to mix, on the same shoulder portion, lateral grooves having a plurality of recesses and lateral grooves having a single recess in an alternate mode.

[0077] In one embodiment of this invention, the lateral grooves (17, 21) comprising one or more recesses 27 of the outer shoulder portion 11 and/or of the inner shoulder portion 15 have a depth that is reduced by comparison to lateral grooves devoid of a recess when present in the tire. For example, the depth of the lateral grooves devoid of a recess is ranging from 120% to 180% of the depth of the lateral groove (17, 21) comprising one or more recesses 27; preferably, from 130% to 170%; more preferably, from 140% to 160%; even more preferably, from 145 to 155%.

[0078] According to a preferred embodiment of this invention, the outside main circumferential groove 3 and/or the inside main circumferential groove 9 have a constant depth which ranges from 5.8 mm to 7.7 mm; for example from 6.0 mm to 7.5 mm; for example, from 6.2 mm to 7.3 mm; for example, from 6.5 mm to 7.0 mm; or for example from 6.7 mm to 7.0 mm.

[0079] For example, the depth of the lateral grooves 17 comprising one or more recesses 27 of the outer shoulder portion ranges from 50% to 85% of the depth of the outside main circumferential groove 3; for example, from 55% to 85%, or from 60% to 85%, or from 60% to 80%, or from 60% to 75%, or from 60% to 70%, or from 65% to 75%. Additionally or alternatively, the depth of the lateral grooves 21 comprising one or more recesses 27 of the inner shoulder portion is ranging from 50% to 85% of the depth of the inside main circumferential groove 9; for example, 55% to 85%, or from 60% to 85%, or from 60% to 80%, or from 60% to 75%, or from 60% to 70%, or from 65% to 75%.

[0080] In an embodiment, the cumulated length of the plurality of recesses in the lateral grooves or the length of the single recess 27 of the lateral grooves (17, 21) is ranging from 20% to 60% of the total lateral groove length in the footprint; preferably from 20% to 45%; more preferably from 25 to 40%; and even more preferably from 28% to 35%.

[0081] The one or more recesses 27 may have the same or different length. For example, all the recesses 27 have the same length. For example, at least one of the lateral grooves comprises at least two recesses, and two of said recesses have different length. For example, the cumulated length of the one or more recesses 27 present in the lateral grooves 17 of the outer shoulder portion 11 is different from the cumulated length of the one or more recesses 27 present in the lateral grooves 21 of the inner shoulder portion 15. For example, the recesses of two lateral grooves of the outer shoulder portion (or of the inner shoulder portion) that are consecutive in the circumferential direction of the tire have different length; so lateral grooves with recesses of different length can be distributed in an alternate mode along the circumferential direction of the tire.

[0082] In an embodiment, the depth of the one or more recesses 27 is ranging from 120% to 180% of the depth of the lateral groove (17, 21); preferably, from 130% to 170%; more preferably, from 140 to 160%; even more preferably, from 145% to 155%. For example, all the recesses 27 have the same depth. For example, wherein the lateral grooves comprise at least two recesses, the recesses have a different depth. For example, the recesses of two consecutive lateral grooves in the circumferential direction one shoulder portion of the tire have different depth so lateral grooves with recesses of different depth can be distributed in an alternate mode along the circumferential direction of the tire.

[0083] According to the disclosure, one or more recesses 27 are placed at a distance of the internal ends of the lateral grooves (17, 21); and/or at a distance of the external ends of the lateral grooves (17, 21). For example, one or more recesses 27 are placed at a distance of the ends of the lateral grooves (17, 21). For example, one or more recesses are placed in a central position on the total lateral groove length in the footprint.

[0084] In an embodiment, the one or more recesses 27 (i.e. the single recess or, in case of a plurality of recesses, the recess 27 that is closer to the internal end of the lateral groove) are placed at a distance from the internal end of the lateral grooves (17, 21) of at least 10% of the total lateral groove length in the footprint; preferably at least 15%, more preferably, at least 20%, even more preferably at least 25% and most preferably at least 30%. For example, the one or more recesses 27 are placed at a distance from the internal end of the lateral grooves (17, 21) that is within the range of 10% to 35% of the total lateral groove length in the footprint; preferably from 20% to 30%.

[0085] In an embodiment, the one or more recesses 27 (i.e. the single recess or, in case of a plurality of recesses, the recess 27 that is closer to the external end of the lateral groove) are placed at a distance from the external end of the lateral grooves (17, 21) of at least 10% of the total lateral groove length in the footprint; preferably at least 15%, more preferably, at least 20%, even more preferably at least 25% and most preferably at least 30%. For example, the one or more recesses 27 are placed at a distance from the external end of the lateral grooves (17, 21) which is within the range of 10% to 35% of the total lateral groove length in the footprint; preferably which is within the range of 20% to 30% of the total lateral groove length in the footprint.

[0086] It should be understood that in accordance with this invention the lateral grooves (17, 21) of the outer shoulder portion 11 and/or of the inner shoulder portion 15 comprises at least 2 parts and preferably 3 parts distributed along their length. The first part extends from the internal end to a recess 27 (i.e. the single recess or a first recess), a second part that includes one or more recesses and an optional third part that extends from a recess to the external end. The first part and the optional third part are devoid of a recess.

[0087] In an embodiment, at least one of the lateral grooves 17 of the outer shoulder portion 11 and/or the lateral grooves 21 of the inner shoulder portion 15 shows an extension 29 extending from its internal end to the outside main circumferential groove 3 (or inside main circumferential groove 9, respectively). This allows for improving the noise properties of the tire. The extension 29 has a width smaller than the width of the lateral groove (17, 21) to which it is connected. For example, the extension has a width that is at most 50% the width of the lateral groove; for example, at most 40%; or for example, at most 30%.

[0088] For example, on each shoulder portion, the lateral grooves and the circumferential grooves form blocks each block is comprising one or more sipes (35, 37) extending in the width direction of the tire 1 and the extension 29 and the sipes (35, 37) have the same width.

[0089] For example, the extension 29 of the lateral groove 17 of the outer shoulder portion 11 and/or of the lateral groove 21 of the inner shoulder portion 15 has a depth similar or inferior to the depth of the lateral groove from which it extends. In a preferred embodiment not shown, the extension of the lateral groove of the outer shoulder portion and/or of the lateral groove of the inner shoulder portion has a depth superior to the depth of the lateral groove from which it extends.

[0090] In an embodiment, the outer shoulder portion 11 and/or the inner shoulder portion 15 comprises at least one narrow groove (31, 33) extending in the circumferential direction of the tire that is crossing the lateral grooves (17, 21). For example, the outer shoulder portion 11 and/or the inner shoulder portion 15 comprises a narrow groove (31, 33) extending in the circumferential direction of the tire that is crossing the lateral grooves (17, 21) in the first part of the lateral grooves (17, 21), i.e. in the part that is extending from the internal end of the lateral groove to a recess 27. Thus, the outer shoulder portion 11 may comprise a narrow circumferential groove 31 that divides the outer shoulder portion into two sub-portions namely a central outer shoulder portion and an outside outer shoulder portion wherein the one or more recesses of the lateral grooves are placed in the outside outer shoulder portion. Similarly, the inner shoulder portion 15 may comprise a narrow circumferential groove 33 that divides the inner shoulder portion into two sub-portions namely a central inner shoulder portion and an inside inner shoulder portion wherein the one or more recesses of the lateral grooves are placed in the inside inner shoulder portion. For example, at least one narrow circumferential groove (31, 33) has a width similar to the sipes (35, 37).

[0091] In an embodiment, in the shoulder portions, blocks (23, 25) are formed by the lateral grooves (17, 21), the lateral edges and the circumferential grooves (3, 9). The blocks (23, 25) of the shoulder portions (11, 15) can be interrupted by the narrow circumferential groove (31, 33) that divides them is sub-blocks. Each block (23, 25) may comprise one or more sipes (35, 37) and the sipes (35, 37) connect the narrow circumferential groove (31, 33). In an embodiment, the sipes (35, 37) are distributed asymmetrically from one side to the other of said narrow circumferential groove (31, 33). For example, two sub-blocks of the same block have a different number of sipes; for example, the sub-block that is defined by a lateral edge has a number of sipes 35 that is superior to the number of sipes 37 present in the sub-block that is defined by a main circumferential groove. In an embodiment, the sipes 35 of the sub-block that is defined by a lateral edge and the sipes 37 the sub-block that is defined by a main circumferential groove are not aligned along the axial direction of the tire.

[0092] The subject invention has been described with reference to preferred embodiments. Potential modifications and alterations will occur to others upon a reading and understanding of this description. It is to be understood that all such modifications and alterations are included in the scope of the disclosure as set forth in the appended claims, or the equivalents thereof.