VEHICLE AIR TIRES

Description

[0001] The invention relates to a vehicle pneumatic tire with a profiled tread having at least one circumferential groove extending in the circumferential direction in a top view, with a groove base and two groove flanks, wherein projections acting as sound breakers are arranged distributed around the circumference of the tread in the groove base, wherein each projection has a first plane of symmetry extending in the direction of extension of the circumferential groove in a top view and a second plane of symmetry extending perpendicular to the first plane of symmetry in a top view, and wherein each projection is composed of a central projection part formed in the middle of the circumferential groove and two lateral projection parts facing the groove flanks.

[0002] It is known that circumferential grooves formed on the tread of pneumatic tires, running straight in the direction of the circumference, are particularly advantageous for water drainage and therefore for the tire's aquaplaning performance. To suppress the propagation of sound waves, which primarily form in straight circumferential grooves and whose frequencies lie within a range perceptible to humans, it is common practice to incorporate protrusions in the circumferential grooves that act as noise breakers. However, these protrusions impair water drainage.

[0003] A tire of the type mentioned above is known, for example, from WO 2010 / 102 683 A1. The tread of this tire has circumferential grooves with projections formed at the base of the grooves. According to one embodiment, each projection consists of a central projection positioned in the middle of the circumferential groove and two lateral projections facing the groove flanks. The projections each have the contour of a circular cylindrical surface, with the surface of the lateral projections having a larger radius than that of the central projection. Pneumatic tires with a tread featuring such projections are intended to exhibit reduced tire-road noise and good aquaplaning resistance.

[0004] Further pneumatic tires with circumferential grooves are disclosed in CN 103738121 A, CN 111873719 A, DE 102009003592 A1, DE 102015225941 A1, EP 3789214 A1 and WO 2010102683 A1.

[0005] The invention is based on the objective of further improving the water drainage capacity of the circumferential groove in a vehicle pneumatic tire of the type mentioned above, while maintaining the effect of suppressing sound propagation in the area of ​​the projections.

[0006] The problem is solved according to the invention by, that the central projection part, viewed in top view, has an elongated oval shape in the extension direction of the first plane of symmetry, in particular an elongated elliptical shape in the extension direction of the first plane of symmetry, and is designed in the form of a segment of a radially flattened ovoid, in particular an ellipsoid, wherein the lateral projection parts each have a smaller volume than the central projection part, are nose-shaped and have a nasal bridge descending from the central projection part.

[0007] Due to its shape, the central protrusion is surrounded and over which water flows in a particularly low-turbulence manner when driving on a wet road surface, thus also dividing the water flow in a particularly low-turbulence manner. Since the central protrusion is flattened at its center, a groove cross-section in the area of ​​the protrusion remains advantageously large for water drainage. The protrusions, due to their special design, exhibit an excellent suppression of sound propagation in the circumferential groove.

[0008] According to a preferred embodiment, the central projection is radially flattened by a circular plateau surface running parallel to the periphery of the tread. Such a flattening of the central projection is particularly advantageous for water drainage.

[0009] Another preferred embodiment consists in the central projection being bounded in each direction of extension of the circumferential groove by an end face extending towards the groove base, which forms a portion of the surface of the ovoid or ellipsoid. These end faces are further advantageous for the aforementioned low-turbulence water flow around and over the central projection.

[0010] In the latter preferred embodiment, it is advantageous if each end face, viewed in cross-section in the first plane of symmetry, runs at an angle of 30° to 50°, particularly 35° to 45°, to the radial direction with respect to a straight auxiliary line connecting the ends of the end face. This further contributes to a low-turbulence flow of water over the projection.

[0011] According to a further preferred embodiment, the projection in the second plane of symmetry has a maximum width projected onto the tread periphery of 50% to 85%, in particular 65% to 75%, of the width of the circumferential groove determined in a top view transverse to the direction of extension of the circumferential groove at the tread periphery. This contributes to a further improvement in the water drainage capacity in the circumferential groove in the area of ​​the projection.

[0012] The preferred embodiments mentioned below relate to the dimensions of the projection. These embodiments can be combined with one another as desired and are advantageous with regard to the conflict of objectives between the sound-suppressing effect of the projections and the water drainage capacity of the circumferential groove.

[0013] A first embodiment is characterized in that the central projection part in the first plane of symmetry, viewed in top view, has a maximum length of 10.0 mm to 15.0 mm determined at the level of the profile depth.

[0014] A second embodiment consists in the central projecting part having a maximum height in the radial direction of 25% to 55%, in particular 30% to 50%, preferably 35% to 45% of the profile depth, relative to the level of the profile depth.

[0015] According to a third embodiment, the central projecting part in the second plane of symmetry, viewed in plan view, has a width of 30% to 55%, in particular 35% to 50%, determined at the level of the plateau surface, of the width of the circumferential groove determined in plan view transverse to the extension direction of the circumferential groove at the tread periphery.

[0016] Furthermore, it is advantageous if the lateral projections are spaced apart from the groove flanks, particularly if, in a top view perpendicular to the first plane of symmetry, the spacing is consistent with that of the nearest groove flank. This is especially beneficial for water drainage in the area of ​​the projection, as water is channeled past both sides of the projection equally.

[0017] According to another preferred embodiment, each lateral projection is bounded by a single, outwardly curved surface. This contributes to the fact that water flows around and over the lateral projections in a particularly turbulence-free manner.

[0018] In the latter preferred embodiment, it is advantageous if the outwardly curved surface, viewed in the cross-section lying in the second plane of symmetry, runs at an angle of 30° to 50°, in particular 35° to 45°, to the radial direction with respect to a straight auxiliary line connecting the ends of the outwardly curved surface.

[0019] According to the two subsequent, combinable, further preferred embodiments, the lateral projection parts have dimensions specifically adapted to the central projection part. This contributes to maintaining the sound-suppressing effect and is also advantageous for the water drainage capacity of the circumferential groove.

[0020] One of these embodiments is characterized in that each lateral projection part, viewed from above, has a maximum length of 20% to 35%, in particular 26% to 32%, of the maximum length of the central projection part, determined in the extension direction of the circumferential groove at the level of the groove base.

[0021] A second embodiment of this type is characterized in that each lateral projection part has a maximum height in the radial direction of 60% to 100%, in particular 70% to 90%, preferably 75% to 85% of the maximum height of the central projection part, relative to the level of the profile depth.

[0022] Furthermore, it is particularly advantageous for water drainage if each lateral projection has a volume that is 10% to 25% of the volume of the central projection.

[0023] Another preferred embodiment is characterized in that three to twenty, preferably at least fifteen, projections are formed within the circumferential groove, wherein the arrangement of the projections is in particular such that successive projections have distances from each other in the circumferential direction that are identical or differ from each other by up to 20.0 mm.

[0024] 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. The drawing shows... Fig. 1 an oblique view of a section of a tread of a vehicle pneumatic tire in the area of ​​a circumferential groove with an embodiment of the invention, Fig. 2 a top view of the part of the cutout from Fig. 1 , Fig. 3 a section along line III-III of the Fig. 2 and Fig. 4 a section along line IV-IV of the Fig. 2 .

[0025] Vehicle pneumatic tires designed according to the invention are tires for motor vehicles, in particular for multi-track motor vehicles, and preferably radial tires for passenger cars, vans or light trucks (light trucks with a gross vehicle weight of ≤ 7.5 t).

[0026] Fig. 1 Figure 1 shows an oblique view of a section of the tread of a vehicle tire in the area of ​​a circumferential groove 1, which runs straight in plan view and runs around the circumference, separating profile positives 2, for example, tread bands, from one another. The areas of the tread not shown can be designed in a known manner.

[0027] The circumferential groove 1 is radially oriented to the tread depth T UR specified for the respective tire type ( Fig. 3, Fig. 4 ) executed, which is typically 6.5 mm to 13.0 mm for cars, vans and light trucks, and has a width B UR at the tread periphery in the axial direction ( Fig. 2 , Fig. 3 ) of in particular 6.0 mm to 10.0 mm, furthermore a U-shaped cross-section ( Fig. 3 ) and two groove edges 1a located at the periphery of the tread, extending straight in the circumferential direction in plan view. The circumferential groove 1 is bounded by a groove base 3 and two groove flanks 4. According to Fig. 3 The groove base 3 runs, viewed in the cross-section oriented axially in plan view (cf. position of line III-III in Fig. 2 ), arc-shaped. The groove flanks 4 run, viewed in the aforementioned cross-section, straight and at an angle α of 0° to 15° to the radial direction, in particular from 3° to 10°.

[0028] How Fig. 1 in combination with Fig. 2 As shown, in the section of the circumferential groove 1 shown, there is a component resting on the groove base 3, spaced axially at the same distance from the groove flanks 4, as seen in top view ( Fig. 2 A circumferentially elongated, local projection 5 is formed. The projection 5 acts as a "sound breaker" and reduces the noise emission of the tire during driving, particularly in the frequency range around 1000 Hz. A plurality of projections 5 are provided within the circumferential groove 1, with three to twenty, preferably at least fifteen, projections 5 being provided. The arrangement of the projections 5 is such that successive projections 5 have circumferentially determined distances from one another that are identical or differ from each other by a maximum of 20.0 mm. The difference between the largest and smallest distances is therefore at most 20.0 mm.

[0029] The projection 5 has a symmetry plane E 1 extending circumferentially in top view ( Fig. 2 ) and a plane of symmetry E 2 extending in the axial direction in top view ( Fig. 2 ) and consists of a central projection 6 and two nose-shaped, lateral projections 7 facing the different groove flanks 4. The plane of symmetry E1 is therefore spanned by the circumferential and radial directions, and the plane of symmetry E2 is thus spanned by the axial and radial directions. The projection 5 has a maximum width bv (width at the widest point) projected onto the periphery of the tread in the plane of symmetry E2 and determined in the axial direction. Fig. 2 ) of 50% to 85%, in particular of 65% to 75%, of the width B UR ( Fig. 2 ) of the circumferential groove 1.

[0030] The central projection part 6 is symmetrical with respect to the planes of symmetry E 1 , E 2 ( Fig. 2 ) symmetrical, viewed from above and neglecting the lateral projections 7, has a circumferentially elongated elliptical shape ( Fig. 2 ) and overall the shape of a segment of a radially flattened ellipsoid. The central projection 6 is defined radially by a circular plateau surface 6a running parallel to the tread periphery (cf. Fig. 3, Fig. 4 ) and in each circumferential direction by an end face 6b running between the groove base 3 and the plateau surface 6a (cf. Fig. 4 ), which is a segment of the surface of an ellipsoid.

[0031] The plateau surface 6a is bounded by a circularly circumferential, sharp edge 6a' and flattens the central projection part 6 centrally.

[0032] According to Fig. 4 Each end face 6b runs, viewed in the cross-section lying in the plane of symmetry E 1 (cf. position of line IV-IV in Fig. 2 ), with reference to a straight auxiliary line H 1 connecting the ends of the end face 6b , to the radial direction at an angle β of 30° to 50°, in particular of 35° to 45°.

[0033] According to Fig. 2 bis Fig. 4 The central protrusion part 6 points in the plane of symmetry E 1 ( Fig. 2 ) one in the circumferential direction at the level of the profile depth T UR ( Fig. 4 ) determined maximum length c 1 (length at the longest point, Fig. 2 , Fig. 4 ) from 10.0 mm to 15.0 mm, in the plane of symmetry E 2 ( Fig. 2 ) a width b 1 determined in the axial direction at the level of the plateau surface 6a ( Fig. 2 , Fig. 3 ) of 30% to 55%, in particular of 35% to 50%, of the width B UR ( Fig. 2 , Fig. 3 ) of the circumferential groove 1 as well as one opposite the level of the profile depth T UR ( Fig. 3, Fig. 4 ) maximum height h 1 (height at the highest point) determined in the radial direction, relating to the plateau surface 6a Fig. 3, Fig. 4 ) of 25% to 55%, in particular of 30% to 50%, preferably of 35% to 45% of the profile depth T UR ( Fig.3, Fig. 4 ) on.

[0034] How Fig. 2 Furthermore, the lateral projection parts 7 are each symmetrically designed with respect to the plane of symmetry E 2, wherein one lateral projection part 7 is positioned symmetrically to the other lateral projection part 7 with respect to the plane of symmetry E 1, and wherein each lateral projection part 7 has a smaller volume compared to the central projection part 6.

[0035] Each lateral projection part 7 is furthermore formed by a single, rounded, and therefore edge-free, outwardly curved surface 7a (cf. Fig. 1 ) bounded, which slopes down in the plane of symmetry E 2 from the central projection part 6 towards the groove base 3 and ends at it ( Fig. 3 Each lateral projection 7 thus has a nasal bridge sloping downwards from the central projection 6 towards the groove base 3. The nasal bridge is therefore the part of surface 7a lying in the plane of symmetry E 2 ( Fig. 3 ). According to Fig. 3 The area 7a is considered in the cross-section lying in the plane of symmetry E 2 (cf. position of line III-III in Fig. 2 ), so continuously curved outwards in an arc shape that a straight auxiliary line H 2 connecting the ends of the surface 7a lies within the lateral projection part 7, wherein the surface 7a - with respect to the auxiliary line H 2 - runs at an angle γ of 30° to 50°, in particular of 35° to 45° to the radial direction.

[0036] The lateral projection parts 7 each have a maximum length c 2 (length at the longest point) determined in the circumferential direction at the level of the groove base 3. Fig. 2 ) of 20% to 35%, in particular of 26% to 32%, of the maximum length c 1 ( Fig. 2 ) of the central projection part 6 as well as a maximum height h 2 (height at the highest point) determined in the radial direction relative to the level of the profile depth T UR, Fig. 3 ) of 60% to 100%, in particular of 70% to 90%, especially preferably of 75% to 85%, of the maximum height h 1 ( Fig. 3 ) of the central projection part 6. Preferably, each lateral projection part 7 has a volume which is 10% to 25% of the volume of the central projection part 6.

[0037] In the illustrated embodiment, a circular arc-shaped transition curve 8 is provided between the surfaces 7a of the lateral projection parts 7 and the end faces 6b of the central projection part 6 ( Fig. 1 bis Fig. 3 ) formed, whose two ends lie at the base of the groove 3 ( Fig. 1 ). When determining the corresponding dimensions mentioned (height h 2 and length c 2 of the lateral projection parts 7), the transition rounding 8 is disregarded ( Fig. 2 , Fig. 3 ).

[0038] The invention is not limited to the described embodiment.

[0039] The projections can be attached to one or both groove flanks. Furthermore, each projection can have the shape of a segment of any centrally flattened ovoid. The plateau surface can have a shape different from the one described. The tread has at least one circumferential groove in which the projections are located. Preferably, the projections are formed in each circumferential groove of the tread. Projections located in axially adjacent circumferential grooves are preferably positioned such that the projections from one circumferential groove are offset in the circumferential direction from the projections in the adjacent circumferential groove.

[0040] The circumferential groove(s) containing the projections can, viewed from above, also have a zigzag or wavy shape, wherein this circumferential groove(s) preferably has a "lookthrough", i.e., that, viewed from above in a cross-section oriented axially, a view through the circumferential groove(s) is possible.

[0041] A zigzag-shaped circumferential groove consists of successive circumferential groove segments, each appearing straight in plan view. The projections in zigzag-shaped circumferential grooves possess a first plane of symmetry, which, viewed in plan view, runs in the direction of extension of the circumferential groove, i.e., in the direction of extension of the respective circumferential groove segment. Furthermore, such projections possess a second plane of symmetry, which, viewed in plan view, runs perpendicular to the first plane of symmetry. The first plane of symmetry is therefore defined by the direction of extension of the respective circumferential groove segment and the radial direction. The second plane of symmetry is thus defined by a straight line, perpendicular to the first plane of symmetry in plan view, and the radial direction.The width of the zigzag-shaped circumferential groove is determined in a top view perpendicular to the direction of extension of the circumferential groove as well as at the periphery of the tread.

[0042] In The projections formed by the wavy circumferential grooves are identical to those located in circumferential grooves that run straight in plan view. The direction of extension of a wavy circumferential groove is therefore the exact circumferential direction. Bezugszeichenliste

[0043] 1 Circumferential groove 1a Groove edge 2 Positive profile 3 Groove base 4 Groove flank 5 Projection 6 Central projection part 6a Plateau surface 6a Edge 6b End face 7 Lateral projection part 7a Surface 8 Transition radius b1, BUR Width bV Maximum width c1, c2 Maximum length E1, E2 Plane of symmetry h1, h2 Height H1, H2 Auxiliary line TUR Profile depth α, β, γ Angle

Claims

1. Pneumatic vehicle tyre having a profiled tread with at least one circumferential channel (1) which extends in particular straight in a circumferential direction in plan view and which has a channel base (3) and has two channel flanks (4), wherein, on the channel base (3), there are formed protrusions (5) which are arranged so as to be distributed over the circumference of the tread and which act as sound absorbers, wherein each protrusion (5) has a first plane of symmetry (E1), which extends in the direction of extent of the circumferential channel (1) in plan view, and a second plane of symmetry (E2), which extends perpendicularly to the first plane of symmetry (E1) in plan view, and wherein each protrusion (5) is made up of a central protrusion part (6), which is formed centrally in the circumferential channel (1), and two lateral protrusion parts (7), which face towards the channel flanks (4), characterized in that the central protrusion part (6), when seen in plan view, has an oval shape which is elongate in the direction of extent of the first plane of symmetry (E1), in particular has an elliptical shape which is elongate in the direction of extent of the first plane of symmetry (E1), and is in the form of a portion of an ovoid, in particular ellipsoid, which is flattened centrally in a radial direction, wherein the lateral protrusion parts (7) in each case have a smaller volume in comparison with the central protrusion part (6), are of nose-shaped form and have a nose ridge which descends from the central protrusion part (6).

2. Pneumatic vehicle tyre according to Claim 1, characterized in that the central protrusion part (6) is flattened centrally in the radial direction by a circular plateau surface (6a) which extends parallel to the tread periphery.

3. Pneumatic vehicle tyre according to Claim 1 or 2, characterized in that the central protrusion part (6) is delimited in each direction of extent of the circumferential channel (1) by an end surface (6b) which extends to the channel base (3) and which forms a portion of the surface of the ovoid or of the ellipsoid.

4. Pneumatic vehicle tyre according to Claim 3, characterized in that, when seen in the cross section in the first plane of symmetry (E1), each end surface (6b) extends at an angle (β) of 30° to 50°, in particular of 35° to 45°, to the radial direction on the basis of a straight reference line (H1) which connects the ends of the end surface (6b).

5. Pneumatic vehicle tyre according to one of Claims 1 to 4, characterized in that, in the second plane of symmetry (E2), the protrusion (5) has a maximum width (bV), when projected into the tread periphery, of 50% to 85%, in particular of 65% to 75%, of the width (BUR), determined at the tread periphery transversely to the direction of extent of the circumferential channel (1) in plan view, of the circumferential channel (1).

6. Pneumatic vehicle tyre according to one of Claims 1 to 5, characterized in that, in the first plane of symmetry (E1), the central protrusion part (6), when seen in plan view, has a maximum length (c1), determined at the level of the profile depth (TUR), of 10.0 mm to 15.0 mm.

7. Pneumatic vehicle tyre according to one of Claims 1 to 6, characterized in that, in relation to the level of the profile depth (TUR), the central protrusion part (6) has a maximum height (h1), determined in the radial direction, of 25% to 55%, in particular of 30% to 50%, preferably of 35% to 45%, of the profile depth (TUR).

8. Pneumatic vehicle tyre according to one of Claims 2 to 7, characterized in that, in the second plane of symmetry (E2), the central protrusion part (6), when seen in plan view, has a width (b1), determined at the level of the plateau surface (6a), of 30% to 55%, in particular of 35% to 50%, of the width (BUR), determined at the tread periphery transversely to the direction of extent of the circumferential channel (1) in plan view, of the circumferential channel (1).

9. Pneumatic vehicle tyre according to one of Claims 1 to 8, characterized in that the lateral protrusion parts (7) are spaced apart from the channel flanks (4), in particular are spaced apart correspondingly from the in each case nearest channel flank (4) as determined perpendicularly to the first plane of symmetry (E1) in plan view.

10. Pneumatic vehicle tyre according to one of Claims 1 to 9, characterized in that each lateral protrusion part (7) is delimited by a single outwardly arched surface (7a).

11. Pneumatic vehicle tyre according to Claim 10, characterized in that, when seen in the cross section in the second plane of symmetry (E2), the outwardly arched surface (7a) extends at an angle (γ) of 30° to 50°, in particular of 35° to 45°, to the radial direction on the basis of a straight reference line (H2) which connects the ends of the outwardly arched surface (7a).

12. Pneumatic vehicle tyre according to one of Claims 6 to 11, characterized in that each lateral protrusion part (7), when seen in plan view, has a maximum length (c2), determined at the level of the channel base (3) in the direction of extent of the circumferential channel (1), of 20% to 35%, in particular of 26% to 32%, of the maximum length (c1) of the central protrusion part (6).

13. Pneumatic vehicle tyre according to one of Claims 7 to 12, characterized in that, in relation to the level of the profile depth (TUR), each lateral protrusion part (7) has a maximum height (h2), determined in the radial direction, of 60% to 100%, in particular of 70% to 90%, preferably of 75% to 85%, of the maximum height (h1) of the central protrusion part (6).

14. Pneumatic vehicle tyre according to one of Claims 1 to 13, characterized in that each lateral protrusion part (7) has a volume which is 10% to 25% of the volume of the central protrusion part (6).

15. Pneumatic vehicle tyre according to one of Claims 1 to 14, characterized in that three to twenty, preferably at least fifteen, protrusions (5) are formed within the circumferential channel (1), wherein the arrangement of the protrusions (5) is in particular such that successive protrusions (5) are at distances, determined in the circumferential direction, from one another that correspond or differ from one another by up to 20.0 mm.