PNEUMATIC VEHICLE TIRES

Description

[0001] The invention relates to a pneumatic vehicle tire with a tread having at least one circumferential groove, in particular a straight one, designed to the profile depth, delimited by groove flanks and a groove base with a U-shaped cross-section, with a width determined at the tread periphery in the axial direction, wherein on the groove base, optionally with connection to the groove flanks, a number of projections are formed distributed over the circumference of the circumferential groove, opposite one another in pairs in the axial direction, between each of which a groove path of the circumferential groove extends, extending to the profile depth, having a narrow point, which is designed symmetrically with respect to a plane spanned by the radial direction and a plane perpendicular to the center line of the circumferential groove in plan view, wherein the projections on the groove flanks or on the groove base run out in the circumferential direction and run in such a way that the groove path runs symmetrically with respect to a second plane spanned by the center line of the circumferential groove and the radial direction and, viewed in plan view, is composed of two venturi sections which narrow in a funnel-like manner towards the constriction, wherein the venturi sections have end sections facing one another which together form a path section of the groove path which is elongated in the circumferential direction when viewed in plan view, wherein the constriction of the groove path is located in the path section or is formed by it.

[0002] It is known to incorporate projections in the circumferential grooves of pneumatic tire treads that serve as wear indicators or sound dampeners. These projections act as sound dampeners during driving, reducing the propagation of sound waves that primarily form in straight circumferential grooves and whose frequencies are within a human-perceptible range. Wear indicators are known to be used, in particular, to indicate the legally required minimum tread depth.

[0003] A pneumatic vehicle tire of the type mentioned above is known, for example, from KR 2013 005 725 9 B1. The tread of this pneumatic vehicle tire has a circumferential groove in which projections are formed, arranged in pairs opposite one another in the axial direction and shaped like a segment of a circle when viewed from above. Between the projections, a groove path remains consisting of two funnel-shaped venturi sections, the end sections of which form a circumferentially elongated path section of the groove path, with a constriction of the groove path located in the path section. The projections are intended to reduce tire-road noise while maintaining good aquaplaning performance.

[0004] WO 2019 / 086153 A1 discloses a commercial vehicle tire with a tread having a circumferential groove, on the groove base of which base elevations are distributed circumferentially and centrally positioned, acting as stone ejectors. The base elevations can contact the groove flanks or be spaced axially from them and are each bounded radially by a cover surface with a circumferential surface edge, to which the cover surface slopes downwards. The groove walls have wall sections that are convexly curved relative to one another in plan view, to the sides of the base elevations. The surface edge of the cover surface follows the course of the convexly curved wall sections in such a way that the width of the base elevations decreases toward their circumferential ends.

[0005] DE 10 2014 218 871 A1 discloses a pneumatic vehicle tire with a tread having a circumferential groove in which projections acting as sound absorbers are formed, arranged in pairs opposite one another in the axial direction. One projection has a smaller volume than the other. The smaller projection lies opposite a U-shaped recess formed in the larger projection, penetrating it radially, and extending parallel to the tread periphery. When viewed longitudinally through the circumferential groove, a distance of 2.0 mm to 3.0 mm remains between the projections.

[0006] There are ongoing efforts to further optimize the projections provided in circumferential grooves which act as sound breakers and / or abrasion indicators with regard to their influence on the water drainage capacity of the circumferential groove, in particular to reduce the risk of aquaplaning when driving on wet roads.

[0007] The invention is therefore based on the object of designing the projections in a pneumatic vehicle tire of the type mentioned at the outset in a manner that is more favorable with regard to the water drainage capacity of the circumferential groove.

[0008] The object is achieved according to the invention in that the path section in the circumferential direction has a length of 25% to 35% of the maximum length of the groove path measured in the circumferential direction.

[0009] The Venturi sections of the groove path between the projections accelerate water flowing through the circumferential groove in the area of ​​the projections when driving on wet roads in a swirl-free or low-swirl manner ("Venturi effect"), allowing the water to be directed past the projections more quickly, thus maintaining virtually unchanged water drainage capacity in the area of ​​the projections. This path section is particularly advantageous with regard to the Venturi effect.

[0010] The Venturi sections are particularly effective if their width and / or depth is / are selected or designed according to the following preferred embodiments. Preferably, the projections on the groove path each have a projection edge, wherein the Venturi sections at the narrow point of the groove path have a width determined between the projection edges in the axial direction of at least 1.0 mm and at most 30% of the width of the circumferential groove. In particular, the width of the Venturi sections at the narrow point is at most 25%, preferably at most 20%, of the width of the circumferential groove. Furthermore, it is preferred if the projection edges have a constant distance of 1.4 mm to 2.0 mm, in particular 1.6 mm, from the level of the tread depth in the radial direction. The aforementioned dimensions contribute to giving the Venturi sections a cross-section that is advantageous with regard to the Venturi effect.

[0011] According to a further preferred embodiment, the projections have a constant height of 1.4 mm to 2.0 mm, in particular 1.6 mm, in the radial direction—measured relative to the lowest point of the circumferential groove. In the area of ​​such projections, a relatively large empty groove volume is maintained, which is advantageous with regard to the water drainage capacity of the circumferential groove.

[0012] The effect of the Venturi sections is advantageous if the projections in the circumferential direction have a maximum length of 150% to 300%, in particular of 180% to 250%, particularly preferably of 200% to 230%, of the width of the circumferential groove.

[0013] According to a further preferred embodiment, transverse grooves extending in the region of the projections in front of the circumferential groove run in at least one of the positive profile sections adjacent to the circumferential groove, wherein a channel runs inside the positive profile section between the respective transverse groove and the narrow point of the groove path, into which channel a cut formed in the positive profile section, extending in the radial direction, narrower than the channel and having a width of 0.4 mm to 1.2 mm opens. When driving on a wet road surface, water absorbed by the transverse groove can be quickly drained through the channel into the circumferential groove, wherein the water is directed to the narrow point of the groove path and is therefore effectively accelerated in a favorable manner.

[0014] In this variant, it is advantageous if the channel projects beyond the incision, viewed in cross-section, on each side by 0.15 mm to 2.0 mm, in particular by at least 0.5 mm.

[0015] Furthermore, in this variant it is advantageous if the transverse groove, the channel and the cut are designed symmetrically with respect to the plane spanned by the radial direction and the perpendicular to the center line of the circumferential groove in plan view.

[0016] The projections are designed to be particularly aerodynamic if they are trapezoidal in plan view, with the trapezoid base being located at the groove bottom or at the respective groove flank of the circumferential groove.

[0017] According to a further preferred embodiment, a projection attachment is formed on each of the projections, which is connected to the groove base and / or to the respective groove flank, which projection is overhanged on its outer circumference by the associated projection and which has a constant height of 2.6 mm to 3.4 mm, in particular 3.0 mm, in the radial direction - determined relative to the deepest point of the circumferential groove. The projection attachment, in plan view, preferably has the shape of a trapezoid with a trapezoidal base lying on the respective groove flank or on the groove base of the circumferential groove. Such a projection attachment indicates the reaching of a residual tread depth that is critical, in particular with regard to the water drainage capacity of the circumferential groove.

[0018] It is furthermore advantageous if the pairs of projections which follow one another in the circumferential direction within the circumferential groove have, in particular, corresponding mutual distances of 10.0 mm to 70.0 mm, preferably of at least 30.0 mm.

[0019] In addition, it is advantageous if at least five pairs of projections are formed within the circumferential groove.

[0020] 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 an enlarged oblique view of a section of a tread of a pneumatic vehicle tire in the region of a circumferential groove with an embodiment variant of the invention, Fig. 2 a top view of a part of the section from Fig. 1 , Fig. 3 a section along the line III-III of the Fig. 2 , Fig. 4 a section along line IV-IV of the Fig. 2 and Fig. 5 a section along the line VV of the Fig. 2 .

[0021] Pneumatic vehicle tires designed according to the invention are, in particular, radial tires for passenger cars, vans or light trucks.

[0022] Fig. 1 shows a view of a tread section in the area of ​​a straight, shoulder-side circumferential groove 1, which separates a shoulder-side profile rib 2 from a Fig. 1 only indicated, middle profile rib 3.

[0023] The circumferential groove 1 is designed in the radial direction with the tread depth T 1 intended for the respective tire type, which for cars, vans and light trucks is usually 6.5 mm to 10.0 mm, and has a width B 1 of preferably 6.0 mm to 13.0 mm, in particular of at least 9.0 mm, at the tread periphery in the axial direction. The circumferential groove 1 is delimited by a groove base 4 which is U-shaped in the cross-section of the circumferential groove 1, flat U-shaped in the exemplary embodiment, a groove flank 5 formed on the shoulder-side tread rib 2 and a groove flank 6 formed on the central tread rib 3. In the exemplary embodiment shown, the groove base 4 is composed of a central groove base section 4a running to tread depth T 1 and two lateral transition roundings 4b.The groove flanks 5 adjoin the transition curves 4b without kinks and run in the radial direction, but can also run at the same or different angles of up to 15°, in particular up to 3°.

[0024] In the Fig. 1 In the section of the circumferential groove 1 shown, projections 7 are formed on the groove base 4, at least for the most part on the transition curves 4b, in pairs in the axial direction and offset-free in the circumferential direction, between which a groove path 8 having a constriction and reaching the profile depth T 1 remains or runs.

[0025] The pair of projections 7 acts as a sound dampener and serves as a wear indicator. The projections 7 are made of the rubber material of the tread. A plurality of projection pairs are provided within the circumferential groove 1, which are particularly distributed such that they are spaced apart from each other by distances of 10.0 mm to 70.0 mm, preferably at least 30.0 mm. In the illustrated embodiment, each projection 7 has a projection attachment 9, the design of which will be explained in more detail later.

[0026] According to Fig. 2 the projections 7 and the groove path 8 remaining between them are arranged with respect to a common direction spanned by the axial direction and the radial direction, Fig. 2 The plane E 1 coinciding with the section line IV-IV is symmetrical. Furthermore, the projections 7 are designed such that the groove path 8 is symmetrical with respect to a second plane E 2 spanned by the circumferential direction and the radial direction and extending through the center of the circumferential groove 1.

[0027] How Fig. 1 und Fig. 2 show, the projections 7 are elongated in the circumferential direction in plan view and are of isosceles-trapezoidal design, with the trapezoid base lying on the respective transition curve 4b and with the projections 7 running out in the circumferential direction according to the trapezoidal shape ( Fig. 1 ). The projections 7 have a maximum length I 1 ( Fig. 2 ) from 150% to 300%, in particular from 180% to 250%, particularly preferably from 200% to 230%, of the width B 1 ( Fig. 1 ) of the circumferential groove 1 and in the radial direction - determined from the deepest point of the circumferential groove 1 - a constant height h 1 ( Fig. 3 ) of 1.4 mm to 2.0 mm, in particular of 1.6 mm. The height h 1 therefore preferably corresponds to the statutory minimum tread depth of 1.6 mm prescribed in Germany. Furthermore, the projections 7 are each radially protected by a cover surface 7a ( Fig. 1 , Fig. 3 ) and have projection flanks 7b which delimit the groove path 8 and which connect to the cover surfaces 7a via rounded or kink-free projection edges 7c. The projection edges 7c end at the respective transition curve 4b of the groove base 4 and are each composed of a central edge section 7c' and two end edge sections 7c", wherein the end edge sections 7c" each connect to the central edge section 7c' via a turning point Pw ( Fig. 3 ). The projection flanks 7b are rounded over their entire extent, viewed in the cross-section of the circumferential groove 1, at least in sections, in such a way that they merge into the groove base 4 without kinks ( Fig. 3 ).

[0028] The groove path 8 formed between the projections 7 is composed of two Venturi sections 10 which narrow in a funnel shape or V-shape towards the mentioned narrow point of the groove path 8 (see in particular Fig. 2 ). In the embodiment shown, the Venturi sections 10 have mutually facing end sections, which together form a section that is straight in plan view and U-shaped in cross section ( Fig. 3 ), which form the narrow path section 11 of the grooved path 8 (see in particular Fig. 2 ).

[0029] The Venturi sections 10 have in the plane E 1 a width b 1 determined between the projection edges 7c ( Fig. 2 ) which is at least 1.0 mm and at most 30%, in particular at most 25%, preferably at most 20%, of the width B 1 ( Fig. 1 ) of the circumferential groove 1.

[0030] According to Fig. 2 the path section 11 extends - relative to the projecting edges 7c - up to the turning points Pw and is therefore limited at the level of the cover surfaces 7a by the middle edge sections 7c'. The path section 11 has a length l 2 measured between the turning points Pw of one of the projecting edges 7c in the circumferential direction of 25% to 35% of the maximum length l 1. The middle edge sections 7c' run in the circumferential direction relative to a line connecting their ends and are slightly concavely curved towards one another in plan view, so that the narrow point of the groove path 8 is located at the plane E 1. Alternatively, the middle edge sections 7c' can run straight in the circumferential direction in plan view, so that the narrow point of the groove path 8 is formed by the path section 10.

[0031] How Fig. 1 und Fig. 2 As shown in the drawings, the aforementioned projection attachments 9 are also elongated in plan view and in the circumferential direction and are designed in an isosceles-trapezoidal manner, with the base of the trapezoid lying on the respective groove flank 5, 6 or the respective transition curve 4b. The projection attachments 9 are projected over by the projections 7 and are delimited in the radial direction by a cover surface 9a aligned parallel to the tread periphery ( Fig. 3 ), end in the radial direction - determined from the lowest point or deepest area of ​​the circumferential groove 1 - at a height h 2 ( Fig. 3 ) of 2.6 mm to 3.4 mm, in particular of 3.0 mm, and have a length l 3 ( Fig. 2 ) of 30% to 50%, in particular up to 40%, of the length l 1 of the projections 7.

[0032] In the embodiment shown, in the shoulder-side profile rib 2, next to the projections 7, there is an axially extending groove in front of the circumferential groove 1 at a distance a 1 ( Fig. 2 ) of preferably 2.5 mm to 5.0 mm, which has a width B 2 ( Fig. 2 ) of, for example, 2.0 mm to 5.0 mm and in the radial direction a depth T 2 within the ground contact area preferably corresponding to the profile depth T 1 ( Fig. 4 ). As in particular Fig. 4 shows, a channel 13 located at profile depth T 1 runs between the transverse groove 12 and the path section 11 of the groove path 8. Over the entire extent of the channel 13, a notch 14 extending in the radial direction opens into it (see also Fig. 1 ), which runs between the transverse groove 12 and the circumferential groove 1, has a width of 0.4 mm to 1.2 mm and is continued in the projection 7 adjacent to the profile rib 2, including the projection attachment 9 ( Fig. 1 ). The channel 13 has a rounded, in the embodiment circular, cross-section with a diameter d 1 ( Fig. 5 ) which is selected such that the channel 13 projects beyond the incision 14, viewed in cross section, on each side by 0.15 mm to 2.0 mm, in particular by at least 0.5 mm.

[0033] Both the transverse groove 12, the notch 14 and the channel 13 are symmetrical with respect to the mentioned plane E 1 ( Fig. 2 , Fig. 4 ), therefore extend in the axial direction or are aligned in the axial direction.

[0034] The invention is not limited to the described embodiment.

[0035] In particular, the projections 7 can also be formed in central circumferential grooves. The projection attachments 9 are optional. Bezugsziffernliste

[0036] 1 shoulder-side circumferential groove 2 shoulder-side profile rib 3 middle profile rib 4 groove base 4a groove base section 4b transition rounding 5 groove flank 6 groove flank 7 projection 7a cover surface 7b projection flank 7c projection edge 7c' middle edge section 7c" end edge section 8 groove path 9 projection attachment 9a cover surface 10 venturi section 11 path section 12 transverse groove 13 channel 14 cut a 1 distance B 1 , B 2 , b 1 width d 1 diameter E 1 , E 2 plane h 1 , h 2 height I 1 maximum length I 2 , I 3 length PW turning point T 1 profile depth T 2 depth

Claims

1. Pneumatic vehicle tyre having a tread with at least one, in particular straight, circumferential groove (1) which is formed at profile depth (T1), is delimited by groove flanks (5, 6) and a groove base (4) of U-shaped cross section, and has a width (B1) which is ascertained on the tread periphery in the axial direction, wherein a number of projections (7), which are arranged distributed over the circumference of the circumferential groove (1) and are situated opposite one another in pairs in the axial direction, is formed on the groove base (4), possibly with connection to the groove flanks (5, 6), a groove path (8) of the circumferential groove (1), which groove path reaches profile depth (T1), has a constriction and is of symmetrical configuration with respect to a plane (E1) which is spanned by the radial direction and a vertical to the centre line of the circumferential groove (1) in plan view, running between respective projections, wherein the projections (7) end at the groove flanks (5, 6) or at the groove base (4) in the circumferential direction and run in such a way that the groove path (8) runs symmetrically with respect to a second plane (E2), which is spanned by the centre line of the circumferential groove (1) and the radial direction, and, as viewed in plan view, is made up of two Venturi sections (10) which narrow in the manner of a funnel to form the constriction, wherein the Venturi sections (10) have end sections which face one another and which together form a path section (11) of the groove path (8), which path section is elongate in the circumferential direction in plan view, wherein the constriction of the groove path (8) is located in the path section (11) or is formed by said path section, characterized in that the path section (11) has, in the circumferential direction, a length (l2) of from 25% to 35% of the maximum length (l1) of the groove path (8) measured in the circumferential direction.

2. Pneumatic vehicle tyre according to Claim 1, characterized in that the projections (7) on the groove path (8) each have a projection edge (7c), wherein the Venturi sections (10) at the constriction of the groove path (8) have a width (b1), which is ascertained between the projection edges (7c) in the axial direction, of at least 1.0 mm and at most 30% of the width (B1) of the circumferential groove (1).

3. Pneumatic vehicle tyre according to Claim 2, characterized in that the width (b1) of the Venturi sections (10) at the constriction is at most 25%, in particular at most 20%, of the width (B1) of the circumferential groove (1).

4. Pneumatic vehicle tyre according to Claim 2 or 3, characterized in that the projection edges (7c) are at a constant distance of from 1.4 mm to 2.0 mm, in particular of 1.6 mm, from the level of the profile depth (T1) in the radial direction.

5. Pneumatic vehicle tyre according to one of Claims 1 to 4, characterized in that the projections (7) have a constant height (h1) of from 1.4 mm to 2.0 mm, in particular of 1.6 mm, in the radial direction - ascertained in relation to the lowest point of the circumferential groove (1).

6. Pneumatic vehicle tyre according to one of Claims 1 to 5, characterized in that the projections (7) have a maximum length (l1) of from 150% to 300%, in particular of from 180% to 250%, particularly preferably of from 200% to 230%, of the width (B1) of the circumferential groove (1) in the circumferential direction.

7. Pneumatic vehicle tyre having a tread with profile positives (2, 3) which adjoin the circumferential groove (1) and run around in the circumferential direction according to one of Claims 1 to 6, characterized in that transverse grooves (12) which end in front of the circumferential groove (1) run in at least one of the profile positives (2, 3) in the region of the projections (7), wherein a channel (13) runs in the interior of the profile positive (2) between the respective transverse groove (12) and the constriction of the groove path (8), a sipe (14) which is formed in the profile positive (2), extends in the radial direction, is designed to be narrower than the channel (13) and has a width of from 0.4 mm to 1.2 mm issuing into said channel.

8. Pneumatic vehicle tyre according to Claim 7, characterized in that the channel (13) protrudes beyond the sipe (14), as viewed in cross section, by from 0.15 mm to 2.0 mm, in particular by at least 0.5 mm, on each side.

9. Pneumatic vehicle tyre according to Claim 7 or 8, characterized in that the transverse groove (12), the channel (15) and the sipe (14) are of symmetrical design with respect to the plane (E1) which is spanned by the radial direction and the vertical to the centre line of the circumferential groove (1) in plan view.

10. Pneumatic vehicle tyre according to one of Claims 1 to 9, characterized in that the projections (7) are of trapezoidal design in plan view, wherein the base of the trapezoid lies on the groove base (4) or on the respective groove flank (5, 6) of the circumferential groove (1).

11. Pneumatic vehicle tyre according to one of Claims 1 to 10, characterized in that a projection attachment (9) which is integrally formed on the groove base (4) and / or on the respective groove flank (5, 6) is formed on the respective projections (7), the associated projection (7) protruding beyond said projection attachment at its outer circumference and said projection attachment having a constant height (h2) of from 2.6 mm to 3.4 mm, in particular of 3.0 mm, in the radial direction - ascertained in relation to the lowest point of the circumferential groove (1), wherein the projection attachment (9) preferably has, in plan view, the shape of a trapezoid with a trapezoid base which is situated on the respective groove flank (5, 6) or on the groove base (4) of the circumferential groove (1).

12. Pneumatic vehicle tyre according to one of Claims 1 to 11, characterized in that the pairs of projections (7) which follow one another in the circumferential direction within the circumferential groove (1) are at, in particular, corresponding mutual distances of from 10.0 mm to 70.0 mm, preferably of at least 30.0 mm.

13. Pneumatic vehicle tyre according to one of Claims 1 to 12, characterized in that at least five pairs of projections (7) are formed within the circumferential groove (1).