tread and pneumatic tires with such a tread

Abstract

Tread area for a tire (1) comprising: a first tread zone (11) extending continuously and completely around the tire (1) in the circumferential direction when the tread (10) is applied to the tire (1), wherein the first tread zone (11) is formed from a first composition; a second tread zone (12) extending continuously and completely around the tire (1) in the circumferential direction when the tread (10) is applied to the tire (1), wherein the second tread zone (12) is formed from a second composition that differs from the first composition; and a boundary groove (13) that axially separates the first tread zone (11) from the second tread zone (12); wherein the first tread zone (11), the second tread zone (12) and the boundary groove (13) completely form the tread (10) or at least completely form the part or layer of the tread (10) that comes into contact with a road when the tread (10) is applied to the tire (1) and the tire (1) is mounted on a vehicle, inflated to normal tire pressure and under standard load; wherein the limiting groove (13) has an axial centerline which is spaced an axial distance (D) from a longitudinal centerline plane (EP) of the tire (1) or the tread (10); and wherein the first tread zone (11) has a first circumferential groove (112) and a sidewall section that defines an intermediate circumferential rib (113) of the first tread zone (11) and a shoulder circumferential rib (114) of the first tread zone (11); characterized in that the intermediate circumferential rib (113) includes curved blind lamellae (1132) which extend axially away from the limiting groove (13).

Description

Field of the invention

[0001] The present invention relates to pneumatic tires, treads for pneumatic tires, and more particularly to a tire tread and a pneumatic tire having a tread, which is preferably designed as an all-season tire and which provides improved driving performance in snow-covered road conditions and, on the other hand, steering stability in dry road conditions. State of the art

[0002] Conventional pneumatic tires such as the Goodyear Vector 4Season Gen3 (see EU Design No. 005684537-0007) sometimes include a first tread pattern formed between a tire longitudinal centerline and one of the tread edges, and a second tread pattern formed between the tire longitudinal centerline and the other of the tread edges, wherein the first tread pattern and the second tread pattern are formed as a substantially line-symmetric shape with respect to the tire longitudinal centerline and are offset with respect to each other in a tire circumferential direction.The first and second tread patterns may each be provided with lateral inclined grooves, inner and outer connecting grooves, and central connecting grooves, each extending across the tire longitudinal centerline to connect one of the lateral inclined grooves arranged on the first tread pattern with one of the lateral inclined grooves arranged on the second tread pattern.

[0003] Thus, the tread portion may include a series of central blocks divided by the lateral inclined grooves, the inner connecting grooves, and the central connecting grooves, a series of center blocks divided by the lateral inclined grooves, the inner connecting grooves, and the outer connecting grooves, and a series of shoulder blocks divided by the lateral inclined grooves and the outer connecting grooves and one of the tread edges. In order to improve traction and braking performance when operating in snow-covered road conditions, a configuration of sipes may be arranged on the central blocks because the central tread region tends to have a longer ground contact length in the circumferential direction. If the sipes are arranged on the central blocks such that the sipes extend along the axial direction of the tire (i.e.perpendicular to the tire's longitudinal centerline), the sipes can scratch the snow road to effectively increase traction.

[0004] From JP-H11-321 237 A a tread for a tire according to the preamble of claim 1 is known. Definitions

[0005] As used herein and in the claims: “Asymmetric tread” means a tread whose tread pattern is not symmetrical about the centre plane or longitudinal centre line (LE) plane of the tyre. “Axial” refers to lines or directions that are parallel to the tire’s axis of rotation. “Circumferential” and “circumferential” mean lines or directions extending along the circumference of the surface of the annular tire parallel to the longitudinal centerline (LE) plane and perpendicular to the axial direction. ‘Longitudinal centreline plane (LE)’ means the plane perpendicular to the tyre’s axis of rotation passing through the centre of the tyre’s tread; or the plane containing the circumferential centreline of the tread. ‘Evolving tread pattern’ means a tread pattern in which the tread intended to come into contact with the road evolves or changes with tread wear, where the evolution or change is predetermined at the time of design of the tyre in order to achieve grip and handling performances that are predetermined throughout the tyre’s service life / wear life or remain substantially unchanged throughout the tyre’s service life / wear life, regardless of the degree of tread wear. “Contact patch” means the contact area of ​​the tread pattern with a flat surface at zero speed and under normal load and pressure. "Groove" means an elongated hollow area in a tread that may extend circumferentially or laterally in a straight, curved, or zigzag pattern around the tread. Circumferential and laterally extending grooves sometimes have sections in common. "Groove width" is the tread surface occupied by a groove or groove section divided by the length of such a groove or groove section; thus, the groove width may be its average width along its length. Grooves may vary in depth within a tire. The depth of a groove may vary around the circumference of the tread, or the depth of an individual groove may be constant but different from the depth of any other groove in the tire.When such narrow or wide grooves are significantly shallower than the wide circumferential grooves they connect, they can be considered "connecting struts," tending to maintain a rib-like character within the respective tread area. As used herein, a groove is intended to have a width large enough to remain open at the contact patch or in the tire's footprint. “Radial” refers to directions radial to or away from the tire’s axis of rotation. "Sipe" or "notch" means small slits molded into the tread elements of the tire that divide the tread surface and improve traction; sipes are preferably designed to close within the contact patch or footprint. “Tread” means a molded-in rubber component which, when bonded to a tire carcass, comprises the part of the tire that comes into contact with the road when the tire is normally inflated and under a normal load. Brief summary of the invention

[0006] The invention relates to a tire tread according to claim 1 and a tire according to claim 11.

[0007] Dependent claims relate to preferred embodiments of the invention.

[0008] The present disclosure has been made in view of the above circumstances and has an object to provide a tire tread and a pneumatic or non-pneumatic tire having such a tread, which have good performance under snow-covered road conditions while maintaining steering stability under dry road conditions.

[0009] A tread for a tire according to a preferred aspect of the present invention includes: a first tread zone extending circumferentially continuously and completely around the tire, the first tread zone being formed of a first composition; a second tread zone extending circumferentially continuously and completely around the tire, the second tread zone being formed of a second composition different from the first composition; and a boundary groove axially separating the first tread zone from the second tread zone, the first tread zone, the second tread zone, and the boundary groove completely forming the tread, the boundary groove having an axial centerline arranged at an axial distance from a longitudinal centerline plane of the tire.The first tread zone has a first circumferential groove and a sidewall portion defining a first tread zone intermediate circumferential rib and a first tread zone shoulder circumferential rib.

[0010] According to a preferred aspect of the tread, the axial distance is between 10 mm and 30 mm, preferably 15 and 25 mm. It is, for example, 20 mm.

[0011] According to another preferred aspect of the tread, the axial distance defines a first tread zone having an axial width that is smaller than an axial width of the second tread zone.

[0012] According to a further preferred aspect of the tread, the second tread zone does not have circumferential grooves extending completely around the tire.

[0013] According to yet another preferred aspect of the tread, the intermediate circumferential rib includes curved grooves extending laterally from the limiting circumferential groove over an entire axial width of the intermediate circumferential rib to the first circumferential groove.

[0014] In the tread according to the invention, the intermediate circumferential rib includes curved blind sipes that extend axially away from the limiting groove.

[0015] According to yet another preferred aspect of the tread, the shoulder circumferential rib includes curved dummy sipes extending axially away from the first circumferential groove.

[0016] According to yet another preferred aspect of the tread, the second tread zone includes first lateral inclined and curved grooves spaced apart from each other in the tire circumferential direction.

[0017] According to yet another preferred aspect of the tread, the second tread zone includes second lateral inclined and curved grooves intersecting the first lateral inclined and curved grooves.

[0018] According to yet another preferred aspect of the tread, the second tread zone includes first lateral inclined and curved sipes that are generally or substantially or largely parallel to the first lateral inclined and curved grooves.

[0019] According to yet another preferred aspect of the tread, the second tread zone includes second lateral inclined and curved sipes extending generally or substantially or largely parallel to the second lateral inclined and curved grooves.

[0020] According to yet another preferred aspect of the tread, the second tread zone includes a circumferential sipe extending circumferentially around the entire second tread zone.

[0021] According to yet another preferred aspect of the tread, the circumferential sipe has an axial width in a range of 1.0 mm to 2.0 mm, such as 1.5 mm.

[0022] According to yet another preferred aspect of the tread, the circumferential sipe has a radial depth in a range of 5 mm to 7 mm.

[0023] According to yet another preferred aspect of the tread, the second tread zone includes "microgrooves" to increase traction during acceleration / braking of the tire.

[0024] Further disclosed is a method for providing a tread for a tire. The method includes the steps of: forming a first tread zone from a first composition; extending the first tread zone circumferentially continuously and completely around the tire; forming a second tread zone from a second composition that differs from the first composition; extending the second tread zone circumferentially continuously and completely around the tire; separating the first tread zone from the second tread zone by a boundary groove; completely forming the tread from the first tread zone, the second tread zone, and the boundary groove; offsetting the boundary groove axially from a longitudinal centerline plane of the tire by a predetermined distance; angling first curved grooves laterally across the second tread zone;Angling second curved grooves laterally across the second tread zone; intersecting the first curved grooves with the second curved grooves; angling first curved sipes generally or substantially or substantially parallel to the first curved grooves; and angling second curved sipes generally or substantially or substantially parallel to the second curved grooves.

[0025] According to a preferred aspect of the method, the second tread zone includes a circumferential sipe extending circumferentially around the entire second tread zone. Short description of the drawings Fig. 1 is a schematic view of a tread pattern of a pneumatic tire according to the present invention. Fig. Figure 2 is an enlarged schematic view of the tread pattern of Fig. 1. Fig. Figure 3 is a schematic cross-sectional view taken along line 3-3 of Fig. 2. Fig. Figure 4 is a detailed schematic perspective view of a portion of the tread pattern of Fig. 1 and Fig. 2. Fig. Figure 5 is a detailed schematic perspective view of another part of the tread pattern of Fig. 1 and Fig. 2. Description of preferred embodiments of the present invention

[0026] As in the Fig. 1 to 3, an exemplary tire 1 according to the present invention includes a first tread zone 11 extending circumferentially continuously and completely around the tire 1 and a second tread zone 12 extending circumferentially continuously and completely around the tire 1.

[0027] In this exemplary tire 1, the first tread zone 11 is axially adjacent to the second tread zone 12, and the first and second tread zones together form a complete tread 10 for the tire 1, or at least form the complete part or all of the layer of the tread 10 that comes into contact with the road when the tire is mounted on a vehicle, inflated to normal tire pressure, and under standard load.

[0028] The first tread zone 11 is preferably formed from a first composition suitable for summer driving conditions. Such a first composition resists deformation and provides excellent grip under dynamic driving conditions.

[0029] The second tread zone 12 is preferably formed from a second, different composition suitable for winter driving conditions. Such a second composition improves performance in snow / ice / wet conditions and effectively sheds water and slush.

[0030] As in the Fig. 1 to 3, the first tread zone 11 preferably has an axial width that is less than half the total axial width of the tread 10. The first tread zone 11 preferably has one circumferential groove 112. The second tread zone 12 preferably has no main circumferential grooves ( Fig. 1 to 2).

[0031] The first tread zone 11 is axially separated from the second tread zone 12 by a circumferential boundary groove 13.

[0032] The first tread zone 11 preferably includes an intermediate circumferential rib 113 and a shoulder circumferential rib 114 defined by a sidewall 3 of the tire 1, the circumferential groove 112 of the first tread zone 11 and the boundary circumferential groove 13.

[0033] An axial centerline of the circumferential boundary groove 13 is arranged at an axial distance D from the longitudinal centerline plane LE of the tire 1, whereby the first tread zone 11 has an axial width which is smaller than that of the second tread zone 12.

[0034] The axial distance D is preferably in a range from 10.0 mm to 30.0 mm or from 15.0 to 25.0 mm, such as 20.0 mm.

[0035] The intermediate circumferential rib 113 preferably includes curved grooves 131 extending laterally from the limiting circumferential groove 13 across an entire axial width of the intermediate circumferential rib to the circumferential groove 112. The intermediate circumferential rib 113 further includes curved dummy ribs 1132 extending axially away from the limiting circumferential groove 13.

[0036] The shoulder circumferential rib 114 preferably includes curved grooves 1141 extending laterally from the circumferential groove 112 across an entire axial width of the shoulder circumferential rib to the sidewall 3. The shoulder circumferential rib 113 may further include curved dummy ribs 1142 extending axially away from the circumferential groove 112.

[0037] The second tread zone 12 preferably includes first lateral inclined and curved grooves 121 spaced apart from each other in the tire circumferential direction and second lateral inclined and curved grooves 122 intersecting the first lateral inclined grooves.

[0038] As in Fig. 2, both the first lateral inclined and curved grooves 121 and the second lateral inclined and curved grooves 122 preferably originate from the same lateral groove adjacent to an opposite sidewall 3 of the tire 1.

[0039] The second tread zone 12 preferably further includes first lateral inclined and curved sipes 123 generally parallel to the first lateral inclined and curved grooves 121 and second lateral inclined and curved sipes 124 generally parallel to the second lateral inclined and curved grooves 122.

[0040] The second tread zone 12 preferably further includes a circumferential sipe 125 extending circumferentially around the entire second tread zone. The sipe 15 helps dissipate heat, thereby helping to improve rolling resistance and fuel consumption from the second tread zone 12 to the overall tread pattern 10.

[0041] The circumferential lamella 125 preferably has an axial width between 1.0 mm and 2.0 mm or 1.3 mm and a radial depth between 5 mm and 7 mm or 6 mm.

[0042] The second tread zone 12 may also include "microgrooves" 127 to increase traction during acceleration / braking. Such "microgrooves" preferably have a width in a range of 0.1 to 0.8 mm, preferably 0.1 to 0.5 mm or 0.1 mm to 0.3 mm, and / or a radial depth in a range of 2 to 8 mm, preferably 2 to 6 mm or 2 to 4 mm.

[0043] As in the Fig. 4 to 5, the grooves 1131, 1141 and the sipes 1132 (not shown), 1142 of the first tread zone 11 preferably terminate at the grooves 13, 112 with notches 1133, 1143 that develop during tread wear and form additional and developing traction edges 1137, 1147 for improved wet / snow traction.

[0044] Preferably, the notches 1133, 1143 widen as they project radially inward and axially inward ( Fig. 4 to 5).

[0045] The use of the notches 1133, 1143 at endpoints of the grooves 1131, 1132, 1141, 1142 while the grooves intersect with the main circumferential grooves 13, 112 creates additional cavities in the tire 1 in which snow can be captured and maintained to generate additional snow-on-snow shear force.

[0046] The notches 1133, 1143 must not compromise the circumferential groove volume so that there is no negative impact on wet or hydroplaning performance (e.g., notches advantageously add additional wet cavity to the circumferential grooves), and may eliminate sharp block corners (90 degrees or less) for better wear performance and handling (e.g., similar to block edge / corner chamfering (not shown)). Further, adjacent to the notches 1133, 1143, substantially L-shaped teeth 1135 may be arranged at the base of the grooves 13, 112 to further reinforce the grooves and ridges 113, 114 for improved dry / wet handling. Such teeth 1135 may also enhance snow capture and thereby improve the shear traction of the first tread zone 11. The L-shaped teeth 1135 can extend axially further into the grooves 13, 112, while the teeth protrude radially inwards ( Fig. 4 to 5).

Claims

[1] Tread for a tire (1) comprising: a first tread zone (11) extending circumferentially continuously and completely around the tire (1) when the tread (10) is applied to the tire (1), the first tread zone (11) being formed from a first composition; a second tread zone (12) extending circumferentially continuously and completely around the tire (1) when the tread (10) is applied to the tire (1), the second tread zone (12) being formed from a second composition different from the first composition; and a boundary groove (13) axially separating the first tread zone (11) from the second tread zone (12); wherein the first tread zone (11), the second tread zone (12) and the boundary groove (13) completely form the tread (10) or at least completely form the part or layer of the tread (10) that comes into contact with a road when the tread (10) is applied to the tire (1) and the tire (1) is mounted on a vehicle, inflated to normal tire pressure and under standard load; wherein the limiting groove (13) has an axial center line which is spaced by an axial distance (D) from a longitudinal center line plane (EP) of the tire (1) or the tread (10); and wherein the first tread zone (11) has a first circumferential groove (112) and a sidewall portion defining an intermediate circumferential rib (113) of the first tread zone (11) and a shoulder circumferential rib (114) of the first tread zone (11); characterized bythat the intermediate circumferential rib (113) includes curved dummy lamellae (1132) extending axially away from the limiting groove (13). [2] Tread according to claim 1, wherein the axial distance (D) is in a range of 10 mm to 30 mm and / or wherein the axial distance (D) defines the first tread zone (1) with an axial width which is smaller than an axial width of the second tread zone (12). [3] Tread according to claim 1 or 2, wherein the second tread zone (12) does not have circumferential grooves extending completely around the tire (1) or the tread (10). [4] A tread according to at least one of the preceding claims, wherein the intermediate circumferential rib (113) includes curved grooves (1131) extending laterally from the limiting circumferential groove over an entire axial width of the intermediate circumferential rib (113) to the first circumferential groove (112). [5] A tread according to at least one of the preceding claims, wherein the shoulder circumferential rib (114) includes curved dummy sipes (1142) extending axially away from the first circumferential groove (112). [6] A tread according to at least one of the preceding claims, wherein the second tread zone (12) includes first lateral inclined and curved grooves (121) spaced circumferentially from each other, and optionally wherein the second tread zone (12) includes second lateral inclined and curved grooves (124) intersecting the first lateral inclined and curved grooves (121). [7] A tread according to at least one of the preceding claims, wherein the second tread zone (12) includes first lateral inclined and curved sipes (123) generally parallel to the first lateral inclined and curved grooves (121), and / or wherein the second tread zone (12) includes second lateral inclined and curved sipes generally parallel to the second lateral inclined and curved grooves (124). [8] A tread according to at least one of the preceding claims, wherein the second tread zone (12) includes a circumferential sipe (125) extending circumferentially along or around the entire second tread zone (12). [9] Tread according to claim 8, wherein the circumferential sipe (125) has an axial width in a range of 1.0 mm to 2.0 mm and / or a radial depth in a range of 5 mm to 7 mm. [10] Tread according to at least one of the preceding claims, wherein the second tread zone (12) includes microgrooves (127) for increasing traction during acceleration / braking of the tire (1). [11] A tire having a tread (10) according to at least one of the preceding claims.

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