VEHICLE AIR TIRES

Description

[0001] The invention relates to a pneumatic vehicle tire with a directional tread with diagonal grooves extending in a V-shape relative to one another across the tread width and merging into one another, wherein in each tread half, between circumferentially adjacent diagonal grooves, at least two grooves are arranged which are inclined in the opposite direction to the diagonal grooves in plan view and each have two groove flanks and a groove base, wherein the diagonal grooves and the grooves delimit shoulder-side profile blocks belonging to two shoulder-side profile block rows and middle profile blocks located in a central tread area, wherein grooves are provided which are inclined in the opposite direction to the diagonal grooves and each have a number of projections on their groove flanks,wherein - viewed over the extent of the associated groove - a projection located on one groove flank alternately follows a projection located on the other groove flank and wherein a groove base path running along the projections remains at the groove base.

[0002] Such a pneumatic vehicle tire is known, for example, from DE 10 2017 211 130 A1. The tire has a directional tread with diagonal grooves extending in a V-shape across the tread width, merging into one another, and grooves extending between these grooves. Grooves are provided, on the groove flanks of which at least one wedge-shaped projection is formed, wherein the projections overlap one another, viewed in the direction of extension of the groove. A groove base path with a width of 0.5 mm to 1.5 mm runs between the projections extending from opposite groove flanks and between each projection and the opposite groove flank. The tread blocks are supported on the projections under load, thereby stabilizing them and thus improving traction and braking properties on snow.The protrusions cause snow to accumulate in the grooves when driving on snow-covered roads, ensuring good snow-on-snow friction. The tire is thus well-balanced in terms of its handling characteristics under winter driving conditions.

[0003] The invention is based on the object of reducing the risk of aquaplaning in a pneumatic vehicle tire of the type mentioned above, while maintaining the advantageous traction, braking and grip properties on snow.

[0004] The stated object is achieved according to the invention in that the projections each have the shape of a pyramid with exactly two triangular boundary surfaces and a radially outer tip located on the groove flank, wherein at least three adjacent projections are formed on each groove flank, which give the groove base path a zigzag-shaped course in plan view.

[0005] Due to the special shape of the pyramid-shaped protrusions, the "transverse portion" of the groove base path running between them is significantly reduced compared to the conventional wedge-shaped protrusions. This allows water to flow through the groove with minimal or almost no turbulence when driving on wet roads, significantly reducing the risk of aquaplaning. The pyramid-shaped protrusions continue to optimally support the tread blocks under load, thus maintaining particularly advantageous traction, braking, and grip properties on snow.

[0006] According to a first preferred embodiment, each projection has a radially oriented plane of symmetry extending perpendicular to the groove centerline in plan view, in which plane the two triangular boundary surfaces have a common boundary edge inclined to the radial direction, which, viewed in plan view, ends either on or in front of the groove centerline. Therefore, in this embodiment, the triangular boundary surfaces of a projection do not extend beyond the groove centerline, further improving water drainage along the groove base path and through the groove to the nearest inclined groove.

[0007] For water drainage, it is additionally advantageous if, according to a first preferred embodiment, the common boundary edge of the two triangular boundary surfaces, viewed in plan view, ends in front of the groove center line at a distance of at least 0.1 mm determined perpendicular to this.

[0008] In this case, it is advantageous if, in the first preferred embodiment, the common boundary edge of the two triangular boundary surfaces extends at an angle of 15° to 35°, in particular 20° to 30°, to the radial direction. This configuration is particularly advantageous for the aforementioned supporting effect of the projections.

[0009] A further preferred embodiment is characterized in that the triangular boundary surfaces each have a radially inner boundary edge extending at a constant depth determined in the radial direction, which extends at an angle of 25° to 50°, in particular 30° to 45°, relative to the groove centerline. This configuration is also particularly advantageous for the mutual support of the projections and for good water drainage through the groove base path.

[0010] It is also advantageous if the groove base path has a width, determined vertically between the radially inner boundary edges, of 30% to 50%, in particular of 35% to 45%, of the width of the groove determined at the tread periphery.

[0011] According to a further preferred embodiment, the triangular boundary surfaces each have a boundary edge running along the groove flank, which is inclined to the radial direction at an angle of 15° to 35°, in particular 20° to 30°. Such boundary surfaces also improve the supporting effect of the projections.

[0012] According to a further preferred embodiment, the radially outer tip of each projection is located at a height of 20% to 60%, in particular 30% to 50%, preferably 35% to 45%, of the maximum depth of the groove, measured in the radial direction, relative to the deepest point of the groove. This contributes primarily to improving water drainage in the grooves.

[0013] A further preferred embodiment is characterized in that the grooves, which have adjacent projections on their flanks, have at least four adjacent projections on each flank. By having at least four projections, an extremely advantageous supporting effect can be achieved with a relatively small rubber volume (the volume of all projections in a groove) compared to grooves with fewer projections.

[0014] In this context, it is furthermore advantageous if the grooves which have the projections adjacent to one another on their groove flanks have at least four, in particular exactly four, projections on one groove flank and at least five, in particular exactly five, projections on the other groove flank.

[0015] According to a further preferred embodiment, in each tread half, three grooves extend between circumferentially adjacent oblique grooves, inclined to the oblique grooves. The projections are formed at least, in particular exclusively, in the two grooves extending further outward of the tread. The supporting effect of the projections is particularly advantageous, especially when cornering, with regard to traction, braking, and grip on snow. The grooves extending furthest toward the inside of the tread, in contrast, are free of projections, which is particularly beneficial for water drainage.

[0016] In order to achieve a good balance between the stiffness and the drainage behavior of the tread, it is advantageous if the grooves have a depth of 75% to 100%, in particular 80% to 90%, of the profile depth in the radial direction and a width of 2.0 mm to 6.0 mm, in particular 3.0 mm to 5.0 mm.

[0017] To achieve low rolling noise, it is also advantageous if the grooves, viewed in plan view and relative to their groove center lines, run at an angle of 15° to 55°, in particular 25° to 45°, to the circumferential direction.

[0018] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows an embodiment of the invention. Fig. 1 a plan view of a partial development of a tread of a pneumatic vehicle tire with an embodiment of the invention, Fig. 2 a section along the line II-II of Fig. 1 , Fig. 3 an enlarged plan view of the detail Z 3 of the Fig. 1 , Fig. 4a section along the line IV-IV of the Fig. 3 , Fig. 5a section along the line VV of the Fig. 3 and Fig. 6 a further enlarged plan view of the detail Z 6 of the Fig. 3 .

[0019] Pneumatic vehicle tires designed according to the invention are tires for multi-track motor vehicles and preferably tires of radial design for passenger cars, vans or light trucks (light trucks with a GVW ≤ 7.5 t).

[0020] Fig. 1 shows a plan view of a partial development of a tread belonging to a pneumatic vehicle tire with a directional tread pattern. The pneumatic vehicle tire must be mounted on the vehicle in such a way that it has the rolling direction indicated by arrow R when driving forward. The lateral edges of the ground contact patch (corresponding to the statically determined footprint at a load of 70% of the maximum load capacity at an internal pressure of 85%, determined according to ETRTO standards) are indicated by lines 1, with the ground contact patch having a width B in the axial direction. Furthermore, the tire equatorial plane is marked by line AA.

[0021] The tread has two shoulder-side profile block rows 1 with shoulder-side profile blocks 2 and a central tread area Z with middle profile blocks 3, wherein the shoulder-side profile blocks 2 and the middle profile blocks 3 are separated from each other by oblique grooves 4 and grooves 5. The shoulder-side profile blocks 2 and the middle profile blocks 3 are preferably provided with cuts and / or microgrooves, which in Fig. 1 are not shown and can be implemented in a known manner.

[0022] The oblique grooves 4 run in a V-shape across the tread width, merge into one another in the area of ​​the tire equatorial plane (line AA), extend beyond the lateral edges (lines 1) of the ground contact patch, form the main grooves of the tread and are radially tapered to the respective intended tread depth TP ( Fig. 2 ) of usually 6.5 mm to 13.0 mm, wherein the oblique grooves 4, which each extend beyond the same lateral edge (line 1) of the ground contact patch, run parallel to one another when viewed from above. The oblique grooves 4 extending beyond one lateral edge (line 1) of the ground contact patch are offset in a barely perceptible manner in the circumferential direction from the oblique grooves 4 extending beyond the other lateral edge (line 1) of the ground contact patch. The rolling direction of the tire when driving forward (arrow R) is such that the oblique grooves 4 first enter the ground with their ends on the inside of the tread when driving forward.

[0023] Each oblique groove 4, viewed in plan view, is composed of a slightly curved, tread-side groove section 4a and a shoulder-side groove section 4b that is more inclined to the circumferential direction, and has a groove center line m SR. The tread-side groove section 4a has - relative to the groove center line m SR - a length la projected in the axial direction of 25% to 35% of the width B of the ground contact area and - likewise relative to the groove center line m SR - runs at an angle α of 30° to 55° to the axial direction, wherein the angle α is determined with respect to a tangent locally applied to the groove center line m SR. The shoulder-side groove section 4b runs - relative to the groove center line m SR - at an angle β of 0° to 15°, in particular of up to 10°, to the axial direction.

[0024] In each tread half, three of the already mentioned grooves 5 are formed between circumferentially adjacent oblique grooves 4, which - based on their groove center lines m N ( Fig. 3 ) - in plan view straight, parallel to each other and to the circumferential direction at an angle γ ( Fig. 3 ) from 15° to 55°, in particular from 25° to 45°, and are inclined in the circumferential direction opposite to the oblique grooves 4. Furthermore, the grooves 4 in the one direction, in Fig. 1 The grooves 5 formed furthest towards the inside of the right tread half, viewed from above, are an extension of the groove sections 4a of the oblique grooves 4 formed in the other tread half.

[0025] The shoulder-side tread blocks 2 are thus delimited by the shoulder-side groove sections 4b, the grooves 5 extending furthest toward the outside of the tread, and by the end sections of the inner tread groove sections 4a adjacent to the shoulder-side groove sections 4b. The middle tread blocks 3 are delimited by the inner tread groove sections 4a and the grooves 5 and, in plan view, have a substantially parallelogram shape, being arranged circumferentially on the "tips" of the parallelograms.

[0026] The further design of the grooves 5 is explained below, in particular using a single groove 5.

[0027] According to Fig. 5 the groove 5 has a maximum depth t N of 75% to 100%, in particular 80% to 90%, of the profile depth TP in the radial direction and a width b N determined at the tread periphery perpendicular to the groove centre line m N (cf. Fig. 3 ) from 2.0 mm to 6.0 mm, especially from 3.0 mm to 5.0 mm. As Fig. 3 in combination with Fig. 5 shows, the groove 5 is formed by a groove flank 5a on the outside of the tread, a groove flank 5b on the inside of the tread and a groove base 5c ( Fig. 5 ), whereby the groove flanks 5a, 5b, viewed in the cross-section perpendicular to the groove center line m N, are at an angle δ ( Fig. 5 ) from 0° to 10°, in particular up to 4°.

[0028] How Fig. 3 und Fig. 4 in combination with Fig. 1 show, in each tread half in the two grooves 5 ( Fig. 1 ) at the groove base 5c ( Fig. 4 ) pyramid-shaped projections 6 ( Fig. 3, Fig. 4 ) is formed, to which projections 6 ( Fig. 3, Fig. 4 ) and adjacent pyramid-shaped projections 6 ( Fig. 3 ) belong. According to Fig. 3 When viewed over the extension of a groove 5 having projections 6, a projection 6 located on the outside of the tread groove flank 5a alternates with a projection 6 located on the inside of the tread groove flank 5b, with the groove base 5c ( Fig. 4 , Fig. 5 ) a groove base path 5d, which runs zigzag-shaped in plan view, remains between the projections 6 formed on the opposing groove flanks 5a, 5b. Furthermore, the projections 6 located at the groove ends directly border an oblique groove 4.

[0029] How Fig. 3 und Fig. 4 show, each projection 6 has a symmetry plane E 1 extending perpendicular to the groove center line m N and oriented in the radial direction, a radially outer tip S located therein and lying on the respective groove flank 5a, 5b, and two triangular boundary surfaces 6a. According to Fig. 4 and Fig. 5 the radially outer tip S is located at a height h V of 20% to 60%, in particular of 30% to 50%, preferably of 35% to 45%, of the maximum depth t N of the groove 5, determined in the symmetry plane E 1 relative to the deepest point of the groove 5 in the radial direction. Fig. 4 the boundary surfaces 6a each have a radially inner boundary edge 7, a boundary edge 8 facing the corresponding groove flank 5a, 5b and a common boundary edge 9 running in the plane of symmetry E 1. The radially inner boundary edge 7 runs at a constant depth determined in the radial direction and, viewed in plan view, at an angle ε ( Fig. 6 ) of 25° to 50°, in particular from 30° to 45°. The boundary edge 8 running along the respective groove flank 5a, 5b is arranged at an angle θ ( Fig. 4 ) of 15° to 35°, in particular of 20° to 30°. The common boundary edge 9 extends to the radial direction at an angle λ ( Fig. 5 ) of 15° to 35°, in particular of 20° to 30°, wherein the common boundary edge 9 - viewed in plan view and relative to its radially inner end - is located in front of the groove center line m N at a distance a 1 ( Fig. 6 ) of preferably at least 0.1 mm, alternatively ends on the groove center line m N.

[0030] The groove base path 5d further has a width b P ( Fig. 6 ), which will be discussed below.

[0031] The mentioned angle λ of the common boundary edge 9 ( Fig. 5 ), the height h V of the projection 6 ( Fig. 5 ) and the mentioned width b N of the groove 5 ( Fig. 6 ) are preferably matched to each other in such a way that the width b P ( Fig. 6 ) of the groove base path 5d 30% to 50%, in particular 35% to 45%, of the mentioned width b N ( Fig. 6 ) of the groove 5.

[0032] According to Fig. 4 and Fig. 6 In the embodiment shown, a transition rounding 10 is formed between each boundary surface 6a and the groove base 5c as well as between each boundary surface 6a and the respective groove flank 5a, 5b.

[0033] The invention is not limited to the described embodiment. In particular, at least two grooves 5 run in each tread half, with at least three projections 6 formed on each groove flank 5a, 5b of the grooves 5. The projections 6 can be formed in all grooves 5 or only in some grooves 5. The transition curves 10 are optional. The oblique grooves 4 can also run continuously curved in plan view, for example. Bezugsziffernliste

[0034] 1 shoulder-side tread block row 2 shoulder-side tread block 3 middle tread block 4 bevelled groove 4 a tread inside groove section 4 b tread outside groove section 5 groove 5 a tread outside groove flank 5 b tread inside groove flank 5 c groove base 5 d groove base path 6 projection 6 a boundary surface 7 radial inner boundary edge 8 boundary edge 9 common boundary edge 10 transition curve A-A line (tire equatorial plane) a 1 distance BWidth b N , b P width E 1 plane of symmetry h V height 1 line (lateral edge of the ground contact patch) la length m N groove center line m SR groove center line RP arrow (rolling direction) S radial outer tip t N maximum depth TP tread depth Z central tread area Z 3 , Z 6 detail α, β, γ, δ, ε, θ, λAngle

Claims

1. Pneumatic vehicle tyre, comprising a directional tread with diagonal grooves (4), which run in a V-shaped manner relative to one another over the tread width and which open into one another, wherein in each tread half there run between circumferentially adjacent diagonal grooves (4) at least two channels (5), which in plan view are inclined in opposite directions relative to the diagonal grooves (4) and each of which comprises two channel flanks (5a, 5b) and a channel base (5c), wherein the diagonal grooves (4) and the channels (5) delimit shoulder-side profile blocks (2), which belong to two shoulder-side rows of profile blocks (1), and central profile blocks (3), which are located in a central tread region (Z), wherein channels (5) which are inclined in opposite directions relative to the diagonal grooves (4) and each of which has a number of projections (6) on their channel flanks (5a, 5b) are provided, wherein - when viewed over the extent of the corresponding channel (5) - a projection (6) located on one channel flank (5a) follows a projection (6) located on the other channel flank (5b) in an alternating manner, and a channel base path (5d) running along the projections (6) remains on the channel base (5c), characterized in that the projections (6) each have the shape of a pyramid with precisely two triangular delimiting areas (6a) and a radially outer tip (S) lying on the channel flank (5a, 5b), wherein on each channel flank (5a, 5b) at least three mutually adjoining projections (6) are formed, giving the channel base path (5d) a zigzagging course in plan view.

2. Pneumatic vehicle tyre according to Claim 1, characterized in that each projection (6) has a plane of symmetry (E1), which in plan view runs perpendicularly to the channel centreline (mN) of the channel (5), is aligned in the radial direction and in which the two triangular delimiting areas (6a) have a common delimiting edge (9) which is inclined in relation to the radial direction and, when considered in plan view, ends either on or before the channel centreline (mN).

3. Pneumatic vehicle tyre according to Claim 2, characterized in that the common delimiting edge (9) of the two triangular delimiting areas (6a), when considered in plan view, ends before the channel centreline (mN) at a distance (a1), determined perpendicularly to this line, of at least 0.1 mm.

4. Pneumatic vehicle tyre according to Claim 2 or 3, characterized in that the common delimiting edge (9) of the two triangular delimiting areas (6a) runs in relation to the radial direction at an angle (λ) of 15° to 35°, in particular of 20° to 30°.

5. Pneumatic vehicle tyre according to one of Claims 1 to 4, characterized in that the triangular delimiting areas (6a) each have a radially inner delimiting edge (7), which runs at a constant depth, determined in the radial direction, and runs in relation to the channel centreline (mN) of the channel (5) at an angle (ε) of 25° to 50°, in particular of 30° to 45°.

6. Pneumatic vehicle tyre according to Claim 5, characterized in that the channel base path (5d) has a width (bP), determined perdendicularly between the radially inner delimiting edges (7), of 30% to 50%, in particular of 35% to 45%, of the width (bN) of the channel (5), determined at the tread periphery.

7. Pneumatic vehicle tyre according to one of Claims 1 to 6, characterized in that the triangular delimiting areas (6a) have a delimiting edge (8), running on the channel flank (5a, 5b), which is inclined in relation to the radial direction at an angle (θ) of 15° to 35°, in particular of 20° to 30°.

8. Pneumatic vehicle tyre according to one of Claims 1 to 7, characterized in that the radially outer tip (S) of each projection (6) is located at a height (hv), determined with respect to the lowest point of the channel (5) in the radial direction, of 20% to 60%, in particular of 30% to 50%, preferably of 35% to 45%, of the maximum depth (tN) of the channel (5), determined in the radial direction.

9. Pneumatic vehicle tyre according to one of Claims 1 to 8, characterized in that the channels (5) which have the mutually adjoining projections (6) on their channel flanks (5a, 5b) have at least four mutually adjoining projections (6) on each channel flank (5a, 5b).

10. Pneumatic vehicle tyre according to one of Claims 1 to 9, characterized in that the channels (5) which have the mutually adjoining projections (6) on their channel flanks (5a, 5b) have at least four, in particular exactly four, projections (6) on one channel flank (5a) and at least five, in particular exactly five, projections (6) on the other channel flank (5b).

11. Pneumatic vehicle tyre according to one of Claims 1 to 10, characterized in that in each tread half there run between circumferentially adjacent diagonal grooves (4) three channels (5) that are inclined in relation to the diagonal grooves (4), wherein the projections (6) are formed at least, in particular exclusively, in the two channels (5) respectively running further to the outside of the tread.

12. Pneumatic vehicle tyre according to one of Claims 1 to 11, characterized in that the channels (5) have in the radial direction a depth (tN) of 75% to 100%, in particular of 80% to 90%, of the profile depth (TP) and a width (bN) of 2.0 mm to 6.0 mm, in particular 3.0 mm to 5.0 mm.

13. Pneumatic vehicle tyre according to one of Claims 1 to 12, characterized in that the channels (5), when considered in plan view and with respect to their channel centrelines (mN), run in relation to the circumferential direction at an angle (γ) of 15° to 55°, in particular of 25° to 45°.