VEHICLE AIR TIRES

Description

[0001] The invention relates to a vehicle pneumatic tire with a tread having at least one circumferentially circumferential profile rib, bounded on at least one side by a circumferential groove, with an outer surface located at the periphery of the tread and, in particular, with transverse grooves running parallel to each other, which end at a distance in front of the circumferential groove, wherein a series of circumferentially extending, arcuately shaped incisions runs between the circumferential groove and the transverse grooves, the curvatures of which point towards the circumferential groove, wherein the arcuate incisions have a circumferentially projected extension length of 30.00 mm to 100.00 mm and an arc shape with a maximum deflection of 2.00 mm to 6.00 mm relative to the chord of the arc.

[0002] Such a pneumatic tire is known, for example, from EP 3 888 950 A1. This pneumatic tire has a tread with a shoulder-side profile rib bounded by a circumferential groove, which is provided with transverse grooves terminating before the circumferential groove. In the area between the circumferential groove and the transverse grooves, circumferentially extending, arcuate in plan view, incisions are formed with a circumferentially projected length of 25.00 mm to 65.00 mm and an arc shape with a maximum deflection of 0.80 mm to 2.00 mm relative to the chord. This tire is intended to provide good water drainage towards the outer shoulder area.

[0003] EP 3 888 949 A1 discloses a vehicle pneumatic tire with a tread featuring a shoulder-side profile rib, which is divided into block-like rib elements by transverse cuts, transverse grooves, and circumferentially arcuate cuts. The transverse cuts terminate on the inside of the tread within the profile rib and open into transverse grooves that extend beyond the width of the tread into the contact patch. The arcuate cuts connect the inner ends or end sections of the circumferentially successive transverse cuts 3, with the curvature of the arc pointing towards the circumferential groove that delimits the profile rib on the inside of the tread. Outside the contact patch, i.e., in the outer shoulder area, each transverse cut is followed by an elongated depression to ensure improved grip performance on soft surfaces, particularly when cornering.

[0004] From EP 3 181 378 A1 and DE 10 2009 044 361 A1, vehicle pneumatic tires with treads are known which have profile ribs on the shoulder side that are structured in a block-like manner by transverse grooves, wherein the transverse grooves end on the inside of the tread within the respective profile rib at a distance from the circumferential groove which limits the profile rib on the inside of the tread.

[0005] The pneumatic tire known from EP 3 230 086 B1 also features a tread with a shoulder-side profile rib in which a multitude of circumferentially spaced transverse grooves are formed. The inner ends of the transverse grooves open into drainage channels that run circumferentially and within the profile rib, with a width of 2.00 mm to 4.00 mm and a depth of 1.50 mm to 3.00 mm. Furthermore, the circumferential drainage channels are widest at their junctions with the transverse grooves to improve water drainage.

[0006] Furthermore, vehicle pneumatic tires with treads are known, for example from EP 2 080 643 B1, in which narrow grooves extending in a circumferential direction are present, which merge into circumferential grooves and into each other.

[0007] The invention is based on the objective of improving the wet performance of a tire of the type mentioned above, in particular the wet grip and traction on wet surfaces, taking into account the stability of the tread rib required for good handling characteristics and abrasion behavior.

[0008] The problem set out in the invention is solved by arranging the arc-shaped incisions with a circumferentially determined mutual distance of their ends of 1.50 mm to 3.00 mm, wherein the arc-shaped incisions have no connections to other grooves or incisions.

[0009] These arc-shaped cuts, with their balanced curvature, provide edges that act both circumferentially and laterally, resulting in improved wet traction in both straight-line driving and cornering. The close spacing of the adjacent cuts is also advantageous for good wet performance, ensuring balanced stability of the tread rib without softening it and promoting even wear. Furthermore, it is beneficial for the stability of the tread rib if the arc-shaped cuts do not connect to other grooves or cuts.

[0010] In a preferred embodiment, the arc-shaped cutouts have a symmetrical arc shape, such that the maximum deflection of the arc occurs at its center. Symmetrically designed cutouts have a particularly balanced influence on the stability of the profile rib.

[0011] In a pneumatic tire where the transverse grooves in the tread rib are arranged according to a pitch length variation, forming pitches of different circumferential lengths, it is particularly advantageous if the arcuate cuts each span at least one pitch length, such that their extent largely correlates with the respective pitch length(s). Specifically, the arcuate cuts each span exactly one pitch length. Such an arrangement of the arcuate cuts is also advantageous for reducing rolling noise.

[0012] For a balanced stiffness of the profile rib, it is advantageous if the arc-shaped incisions have an extension length of 30.00 mm to 60.00 mm.

[0013] Another measure that is advantageous for the stability of the profile rib is that the ends of the arc-shaped incisions have a distance of 5.00 mm to 7.00 mm from the adjacent edge of the circumferential groove, measured in the axial direction.

[0014] The design of the arc-shaped incisions is preferably such that they have a U-shaped cross-section with a rounded incision base, and furthermore have a depth of 1.20 mm to 2.00 mm that is constant along their course and a width of 0.60 mm to 1.20 mm that is constant along their course.

[0015] Profile ribs with arcuate incisions are particularly shoulder-side profile ribs to achieve high stability of the tread to support good handling characteristics.

[0016] Further features, advantages, and details of the invention will now be described in more detail with reference to the schematic drawing, which illustrates an exemplary embodiment. This drawing shows... Fig. 1 a top view of a circumferential section of a shoulder-side profile rib of a tread of a vehicle pneumatic tire and Fig. 2 an enlarged section along line II-II of the Fig. 1 .

[0017] Vehicle pneumatic tires designed according to the invention are in particular radial-type vehicle pneumatic tires for motor vehicles, preferably for passenger cars or light trucks.

[0018] Fig. 1Figure 1 shows an example of a circumferential section of a shoulder-side profile rib 1 extending around the circumference of a tread of a vehicle pneumatic tire, which has an outer surface 1a. The shoulder-side profile rib 1 is bounded on the inside of the tread by a circumferential groove 2, which runs in the circumferential direction and, in the example shown, is straight, with edge edges 2a on the outer surface 1a, the depth of which corresponds to the intended tread depth TP ( Fig. 2 , greatest depth of the deepest groove when the tire is new) which, for passenger car tires, is in the range of 6.00 mm to 8.50 mm. A further tread rib or a row of tread blocks, which is only indicated, connects to the circumferential groove 2. Alternatively, the tread rib 1 is a tread rib running in the central area of ​​the tread, which is bordered on both sides by a circumferential groove. The in Fig. 1The line marked L indicates the lateral edge of the tire's contact patch, determined as the lateral edge of the static footprint when the tire is inflated to its nominal pressure. The tread rib 1 is structured in a block-like manner by a multitude of transverse grooves 3, all of which terminate at an axially determined distance a 1 of 4.00 mm to 15.00 mm in front of the edge 2a of the circumferential groove 2 facing the lateral edge of the contact patch (line L).

[0019] In the illustrated embodiment, the transverse grooves 3 run in a straight or nearly straight line, parallel or largely parallel to each other, and extend axially beyond the lateral edge of the ground contact area (line L). The transverse grooves 3 can also extend at an angle of up to 45° to the axial direction. Furthermore, in the illustrated embodiment, the transverse grooves 3 have a largely constant width between their edge edges on the outer surface 1a of the profile rib 1, which is particularly between 2.00 mm and 4.00 mm. The depth of the transverse grooves 3 within the ground contact area is preferably at least 40% of the profile depth TP. Outside the ground contact area, the transverse grooves 3 taper off with a continuous decrease in depth.

[0020] The profile rib 1 is noise-optimized according to a pitch length variation method, so that, viewed in the circumferential direction, the mutual spacing of the transverse grooves 3 varies. Fig. 1 Three pitches P1, P2, P3 of different circumferences L1 (shortest circumference), L2, L3 (longest circumference), each determined along line L, are shown as examples, with their corresponding pitch boundaries, the lines labeled PG. In the example shown, each pitch P1, P2, P3 has two consecutive transverse grooves 3 in the circumferential direction, with one of these transverse grooves 3 being located in the middle region of the respective pitch.

[0021] Between the inner edge 2a of the circumferential groove 2, which delimits the profile rib 1 on the inside of the tread, and the transverse grooves 3, which terminate at corresponding intervals a 1 in front of this edge 2a, a circumferential series of incisions 4, each with a continuous arc, is formed. The incisions 4 have a circumferential projection length I e of 30.00 mm to 100.00 mm and can be arranged in a row with largely identical or varying projection lengths I e, independent of the position of the transverse grooves 3. In preferred embodiments, the projection lengths I e are adapted to the positions of the transverse grooves 3, such that, for example, and as in Fig. 1As shown, the arc-shaped incisions 4 each span a pitch P 1 , P 2 , P 3, such that the center of the arc is located at the transverse groove 3 running in the middle area of ​​the respective pitch P 1 , P 2 , P 3 and the incisions 4 each end in the immediate vicinity of the transverse grooves 3 immediately following this transverse groove 3.

[0022] The arc shape of the incisions 4 is preferably symmetrical with respect to the center of the arc and such that the in Fig. 1 The dashed lines of the bow chords point towards the transverse grooves 3 and the lateral edge of the ground contact surface (line L), respectively, and the curvatures of the circumferential groove 2. At the center of the bow, the point of greatest deflection is the distance a2 between the center line of the cut 4 and the bow chord, perpendicular to the bow chord, with a distance a2 ranging from 2.00 mm to 6.00 mm.

[0023] The ends of the circumferentially successive incisions 4 are located at intervals a 3 of 1.50 mm to 3.00 mm from each other. The ends of the arcuate incisions 4 have a distance a 4 of 5.00 mm to 7.00 mm from the adjacent edge 2a of the circumferential groove 2, measured in the axial direction.

[0024] How the section view in Fig. 2 As shown, the arcuate incisions 4 have a U-shaped cross-section with a rounded base. The incisions 4 have a depth t 1 that is constant along their length, ranging from 1.20 mm to 2.00 mm, and a width b 1, determined on the outer surface 1a of the profile rib 1, which is between 0.60 mm and 1.20 mm, particularly on the order of 1.00 mm. Reference symbol list

[0025] 1 Profile rib 1a Outer surface 2 Circumferential groove 2a Edge 3 Transverse groove 4 Cut a 1 , a 2 , a 3 , a 4 Spacing b 1 Width (cut) t 1 Depth (cut) L Line (lateral edge of the ground contact area) le Extension length L 1 , L 2 , L 3 Circumferential length of the pitches TP Profile depth P 1 , P 2 , P 3 Pitch PG Pitch limit

Claims

1. Pneumatic vehicle tyre comprising a tread with at least one profile rib (1), which runs around in the circumferential direction, is delimited on at least one side by a circumferential groove (2) and has an outer surface (1a) located on the tread periphery, and with transverse grooves (3), which in particular run parallel to one another and end at a distance before the circumferential groove (2), while between the circumferential groove (2) and the transverse grooves (3) there run a series of circumferentially extending sipes (4), which in plan view are altogether of arcuate form and the curvatures of which are directed towards the circumferential groove (2), the arcuate sipes (4) having a length of extent (le), projected in the circumferential direction, of 30.00 mm to 100.00 mm and an arc shape having a maximum deflection (a2) of 2.00 mm to 6.00 mm with respect to the chord of the arc, characterized in that the arcuate sipes (4) are lined up together at a circumferentially determined mutual distance (a3) of their ends of 1.50 mm to 3.00 mm, the arcuate sipes (4) not having any connections to other grooves or sipes.

2. Pneumatic vehicle tyre according to Claim 1, characterized in that the arcuate sipes (4) have a symmetrical arc shape such that the maximum deflection (a2) of the arc is present in the centre of the arc.

3. Pneumatic vehicle tyre, in which the transverse grooves (3) in the profile rib (1) are arranged according to a variation in pitch length by forming pitches (P1, P2, P3) of different pitch lengths (L1, L2, L3), according to Claim 1 or 2, characterized in that the arcuate sipes (4) each span at least one pitch (P1, P2, P3) in such a way that their lengths of extent (le) largely correlate with the respective pitch length(s) (L1, L2, L3).

4. Pneumatic vehicle tyre according to Claim 3, characterized in that the arcuate sipes (4) each span precisely one pitch (P1, P2, P3).

5. Pneumatic vehicle tyre according to one or more of Claims 1 to 4, characterized in that the arcuate sipes (4) have a length of extent (le) of 30.00 mm to 60.00 mm.

6. Pneumatic vehicle tyre according to one or more of Claims 1 to 5, characterized in that the ends of the arcuate sipes (4) are at a distance (a4) of 5.00 mm to 7.00 mm from the adjacent border edge (2a) of the circumferential groove (2), as determined in the axial direction.

7. Pneumatic vehicle tyre according to one or more of Claims 1 to 6, characterized in that the arcuate sipes (4) have a U-shaped cross section with a rounded sipe base.

8. Pneumatic vehicle tyre according to one or more of Claims 1 to 7, characterized in that the arcuate sipes (4) have a depth (t1), which is in particular constant over their course, of 1.20 mm to 2.00 mm.

9. Pneumatic vehicle tyre according to one or more of Claims 1 to 8, characterized in that the arcuate sipes (4) on the outer surface (1a) of the profile rib (1) have a width (b1), which is in particular constant over their course, of 0.60 mm to 1.20 mm.

10. Pneumatic vehicle tyre according to one or more of Claims 1 to 9, characterized in that the profile rib (1) is a shoulder-side profile rib (1).