PNEUMATIC TYRE FOR A VEHICLE

Abstract

The invention relates to a pneumatic vehicle tyre having a tread with at least one, in particular straight, circumferential groove (1) which is formed at profile depth (T.sub.1), is delimited by groove flanks (5, 6) and a groove base (4) of U-shaped cross section, and has a width (B.sub.1) which is ascertained at 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 (T.sub.1), has a constriction and is of symmetrical configuration with respect to a plane (E.sub.1) which is spanned by the radial direction and a vertical to the centre line of the circumferential groove (1), running between respective projections.

In a tyre of this kind, the projections should be configured in a more expedient manner with respect to the water discharge capacity of the circumferential groove.

This is achieved by way of the projections (7) ending at the groove flanks (5, 6) or at the groove base (4) in the circumferential direction and running in such a way that the groove path (8) runs symmetrically with respect to a second plane (E.sub.2), which is spanned by the centre line of the circumferential groove (1) and the radial direction, and is made up of two Venturi sections (10) which narrow in the manner of a funnel to form the constriction.

Claims

1.-15. (canceled)

16. A pneumatic vehicle tire comprising: a tread with a straight circumferential groove running to a tread depth (T.sub.1) and delimited by groove flanks and a groove base with a U-shaped cross-section, an axial direction on a tread periphery determined width (B.sub.1) a number of projections arranged distributed over a circumference of the circumferential groove, the projections arranged in pairs opposite one another in the axial direction being formed on the groove base and connected to the groove flanks, between which a groove path extends to the profile depth (T.sub.1) and has a constriction, which with respect to a plane (E.sub.1) spanned by a radial direction and a perpendicular to a center line of the circumferential groove is designed symmetrically; the projections run out and run in such a way that the groove path runs symmetrically with respect to a second plane (E.sub.2) spanned by the center line of the circumferential groove and the radial direction, and is composed of two funnel-like constriction venturi sections.

17. The pneumatic vehicle tire according to claim 16, wherein the venturi sections comprising end sections which face one another and together form a path section of the groove path elongated in the circumferential direction in plan view, the groove path forming a constriction.

18. The pneumatic vehicle tire according to claim 17, wherein the path section has a length (l.sub.2) of from 25% to 35% of a maximum length (l.sub.1) of the grooved path measured in the circumferential direction.

19. The pneumatic vehicle tire according to claim 16, the projections on the groove path each have a projection edge and the Venturi sections having a projection edge with a width (b.sub.1) at a narrow point of the groove path, the width determined in the axial direction of at least 1.0 mm and at most 30% of the width (B.sub.1) of the circumferential groove.

20. The pneumatic vehicle tire according to claim 16, a width (b.sub.1) of the venturi sections at the constriction is at most 20% of the width (B.sub.1) of the circumferential groove.

21. The pneumatic vehicle tire according to claim 19, the protruding edges have a constant spacing of from 1.4 mm to 2.0 mm from the level of the profile depth (T.sub.1) in the radial direction.

22. The pneumatic vehicle tire according to claim 16, the projections have a constant height (h.sub.1) of from 1.4 mm to 2.0 mm in the radial direction, as determined relative to a lowest point of the circumferential groove.

23. The pneumatic vehicle tire according to claim 22, the projections, in the circumferential direction, have a maximum length (l.sub.1) of from 150% to 300% of the width (B.sub.1) of the circumferential groove (1).

24. The pneumatic vehicle tire according to claim 16, the tread comprises positive profiles adjoining the circumferential groove and running in the circumferential direction, and in at least one of the positive profiles, in the region of the projections, comprises transverse grooves ending in front of the circumferential groove, with a channel running inside the positive profile between the respective transverse groove and the narrow point of the groove path in which a positive profile formed incision, which extends in the radial direction and is narrower than the channel, has a width of from 0.4 mm to 1.2 mm.

25. The pneumatic vehicle tire according to claim 24, the channel protrudes beyond the incision, as viewed in cross section, on each side by 0.15 mm to 2.0 mm.

26. The pneumatic vehicle tire according to claim, the transverse groove, the channel and the incision, with respect to the plane (E.sub.1) spanned by the radial direction and the perpendicular to the center line of the circumferential groove, are symmetrical.

27. The pneumatic vehicle tire according to claim 16, wherein the projections are trapezoidal in plan view with a trapezium base which lies on the groove base and on the respective groove flank.

28. The pneumatic vehicle tire according to claim 16, further comprising a projection attachment on the projections and connected to the groove base and to the respective groove flank, which on its outer circumference is surmounted by the associated projection, and which in the radial direction, as determined from the lowest point of the circumferential groove, has a constant height (h.sub.2) of from 2.6 mm to 3.4 mm, and wherein the projection attachment, in plan view, has a shape of a trapezium with a trapezium base lying on the respective groove flank and/or on the groove base.

29. The pneumatic vehicle tire according to claim 16, pairs of the projections follow one another within the circumferential groove and have corresponding mutual distances of from 10.0 mm to 70.0 mm.

30. The pneumatic vehicle tire according to claim 29, the pairs of projections comprise at least five pairs of projections.

31. A pneumatic vehicle tire comprising a tread with at least one particular straight circumferential groove (1) running to a tread depth (T.sub.1) and delimited by groove flanks (5, 6) and a groove base (4) with a U-shaped cross-section, with an axial direction on a tread periphery determined width (B.sub.1), a number of projections (7) arranged distributed over a circumference of the circumferential groove (1), arranged in pairs opposite one another in the axial direction being formed on the groove base (4), and optionally connected to the groove flanks (5, 6), between which a groove path (8) of the circumferential groove (1) extends to the profile depth (T.sub.1) and has a constriction, which with respect to a plane (E.sub.1) spanned by a radial direction and a perpendicular to a center line of the circumferential groove (1) is designed symmetrically; wherein the projections (7) on the groove flanks (5, 6) or on the groove base (4) in a circumferential direction run out and run in such a way that the groove path (8) runs symmetrically with respect to a second plane (E.sub.2) spanned by the center line of the circumferential groove (1) and the radial direction, and is composed of two funnel-like constriction venturi sections (10); 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 is elongated in the circumferential direction in plan view, the constriction of the grooved path (8) being located in the path section (11) or formed by the path section (11); and, wherein the path section (11) has a length (l.sub.2) of from 25% to 35% of a maximum length (l.sub.1) of the grooved path (8) measured in the circumferential direction.

32. The pneumatic vehicle tire according to claim 31, wherein the projections (7) on the groove path (8) each have a projection edge (7c), and wherein the Venturi sections (10) at a narrow point of the groove path (8) having a projection edge (7c) have a width (b.sub.1) determined in the axial direction of at least 1.0 mm and at most 30% of the width (B.sub.1) of the circumferential groove (1).

33. A pneumatic vehicle tire comprising a tread with at least one particular straight circumferential groove (1) running to a tread depth (T.sub.1) and delimited by groove flanks (5, 6) and a groove base (4) with a U-shaped cross-section, with an axial direction on a tread periphery determined width (B.sub.1), a number of projections (7) arranged distributed over a circumference of the circumferential groove (1), arranged in pairs opposite one another in the axial direction being formed on the groove base (4), and optionally connected to the groove flanks (5, 6), between which a groove path (8) of the circumferential groove (1) extends to the profile depth (T.sub.1) and has a constriction, which with respect to a plane (E.sub.1) spanned by a radial direction and a perpendicular to a center line of the circumferential groove (1) is designed symmetrically; wherein the projections (7) on the groove flanks (5, 6) or on the groove base (4) in a circumferential direction run out and run in such a way that the groove path (8) runs symmetrically with respect to a second plane (E.sub.2) spanned by the center line of the circumferential groove (1) and the radial direction, and is composed of two funnel-like constriction venturi sections (10); and, wherein the tread comprises positive profiles (2, 3) adjoining the circumferential groove (1) and running in the circumferential direction, and wherein in at least one of the positive profiles (2, 3), in the region of the projections (7), comprises transverse grooves (12) ending in front of the circumferential groove (1), with a channel (13) running inside the positive profile (2 or 3) between the respective transverse groove (12) and the narrow point of the groove path (8), in which a positive profile formed incision (14), which extends in the radial direction and is narrower than the channel (13), has a width of from 0.4 mm to 1.2 mm.

34. The pneumatic vehicle tire according to claim 33, wherein the channel (13) protrudes beyond the incision (14), as viewed in cross section, on each side by 0.15 mm to 2.0 mm.

35. The pneumatic vehicle tire according to claim 33, wherein the transverse groove (12), the channel (15) and the incision (14), with respect to the plane (E.sub.1) spanned by the radial direction and the perpendicular to the center line of the circumferential groove (1), are symmetrical.

Description

[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 exemplary embodiment of the invention. In the drawing,

[0021] FIG. 1 shows an enlarged oblique view of a detail of a tread of a pneumatic vehicle tyre in the region of a circumferential groove with one variant embodiment of the invention,

[0022] FIG. 2 shows a plan view of a portion of the detail from FIG. 1,

[0023] FIG. 3 shows a section along the line of FIG. 2,

[0024] FIG. 4 shows a section along the line IV-IV of FIG. 2, and

[0025] FIG. 5 shows a section along the line V-V of FIG. 2.

[0026] Pneumatic vehicle tyres designed in accordance with the invention are, in particular, tyres of the radial type for passenger cars, vans or light trucks.

[0027] FIG. 1 shows a view of a tread detail in the region of a straight, shoulder-side circumferential groove 1 which separates a shoulder-side profile rib 2 from a central profile rib 3, merely indicated in FIG. 1.

[0028] The circumferential groove 1 is designed, in the radial direction, at the profile depth T.sub.1 which is intended for the respective type of tyre and is usually from 6.5 mm to 10.0 mm for passenger cars, vans and light trucks, and has a width B.sub.1 of preferably from 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 of U-shape in cross section of the circumferential groove 1, in the exemplary embodiment of flat U-shape, a groove flank 5 which is formed on the shoulder-side profile rib 2, and a groove flank 6 which is formed on the central profile rib 3. In the exemplary embodiment shown, the groove base 4, as viewed in cross section of the circumferential groove 1, is made up of a central groove base section 4a, which runs at profile depth T.sub.1, and two lateral rounded transition portions 4b. The groove flanks 5 adjoin the rounded transition portions 4b without a bend and run in the radial direction, but can also run to said rounded transition portions at corresponding or differing angles of up to 15°, in particular of up to 3°.

[0029] In the section of the circumferential groove 1 shown in FIG. 1, projections 7 which are located at least for the most part on the rounded transition portions 4b and are situated opposite one another in pairs in the axial direction and without an offset in the circumferential direction are formed on the groove base 4, a groove path 8 which has a constriction and reaches profile depth T.sub.1 remaining or running between said projections.

[0030] The pair of projections 7 acts as a sound absorber and serves as a wear indicator, wherein the projections 7 are composed of the rubber material of the tread. A large number of projection pairs are provided within the circumferential groove 1, said projection pairs being arranged in a distributed manner, in particular in such a way that they are at mutual distances of from 10.0 mm to 70.0 mm, preferably of at least 30.0 mm, from one another. In the exemplary embodiment shown, a projection attachment 9 is located on each projection 7, the configuration of which projection attachment will be explained in more detail later.

[0031] According to FIG. 2, the projections 7 and the groove path 8 remaining between them are of symmetrical design with respect to a common plane E.sub.1 which is spanned by the axial direction and the radial direction and coincides with section line IV-IV in FIG. 2. Furthermore, the projections 7 are configured in such a way that the groove path 8 is of symmetrical design with respect to a second plane E.sub.2 which is spanned by the circumferential direction and the radial direction and runs through the centre of the circumferential groove 1.

[0032] As shown in FIG. 1 and FIG. 2, the projections 7 are of elongate configuration in the circumferential direction and also configured in the form of an isosceles trapezoid in plan view, wherein the trapezoid base lies on the respective rounded transition portion 4b, and wherein the projections 7 end in a manner corresponding to the trapezoid shape in the circumferential direction (FIG. 1). The projections 7 have a maximum length l.sub.1 (FIG. 2) of from 150% to 300%, in particular of from 180% to 250%, particularly preferably of from 200% to 230%, of the width B.sub.1 (FIG. 1) of the circumferential groove 1 in the circumferential direction and a height h.sub.1 (FIG. 3), which is constant in the exemplary embodiment shown, 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. The height h.sub.1 therefore preferably corresponds to the statutory minimum profile depth of 1.6 mm prescribed in Germany. Furthermore, the projections 7 are each delimited in the radial direction by a top surface 7a (FIG. 1, FIG. 3) which is oriented parallel to the tread periphery and have projection flanks 7b which delimit the groove path 8 and adjoin the top surfaces 7a by means of projection edges 7c which are rounded or run without bends. The projection edges 7c end at the respective rounded transition portion 4b of the groove base 4 and are each made up of a central edge section 7c′ and two end-side edge sections 7c″, wherein the end-side edge sections 7c″ each adjoin the central edge section 7c′ by way of an inflection point P.sub.w (FIG. 3). The projection flanks 7b are rounded at least in sections over their entire extent, as viewed in cross section of the circumferential groove 1, in such a way that they merge with the groove base 4 without bends (FIG. 3).

[0033] The groove path 8, which is formed between the projections 7, is made up of two Venturi sections 10 which each narrow in the manner of a funnel or in a V-shape to form the said constriction of the groove path 8 (see FIG. 2 in particular). In the exemplary embodiment shown, 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 straight in plan view, is U-shaped in cross section (FIG. 3) and has the constriction, (see FIG. 2 in particular).

[0034] The Venturi sections 10 have, in the plane E.sub.1, a width b.sub.1 which is ascertained between the projection edges 7c (FIG. 2) and is at least 1.0 mm and at most 30%, in particular at most 25%, preferably at most 20%, of the width B.sub.1 (FIG. 1) of the circumferential groove 1.

[0035] According to FIG. 2, the path section 11—in relation to the projection edges 7c—reaches as far as the inflection points P.sub.w and is therefore delimited by the central edge sections 7c′ at the level of the top surfaces 7a. The path section 11 has, in the circumferential direction, a length l.sub.2 of from 25% to 35% of the maximum length l.sub.1, which length l.sub.2 is measured between the inflection points P.sub.w of one of the projection edges 7c. The central edge sections 7c′ run, in relation to a line which connects their ends, in the circumferential direction and are bent in a slightly concave manner in relation to one another in plan view, so that the constriction of the groove path 8 is in the plane E.sub.1. As an alternative, the central edge sections 7c′ can be straight in the circumferential direction in plan view, so that the constriction of the groove path 8 is formed by the path section 10.

[0036] As shown in FIG. 1 and FIG. 2, the abovementioned projection attachments 9 are likewise of elongate configuration and also configured in the form of an isosceles trapezoid in plan view and in the circumferential direction, wherein the base of the trapezoid lies on the respective groove flank 5, 6 or the respective rounded transition portion 4b. The projections 7 protrude beyond the projection attachments 9, the projection attachments are delimited in the radial direction by a top surface 9a which is oriented parallel to the tread periphery (FIG. 3), end at a height h.sub.2 (FIG. 3) of from 2.6 mm to 3.4 mm, in particular of 3.0 mm, in the radial direction—determined in relation to the lowest point or lowest region of the circumferential groove 1—and have a length l.sub.3 (FIG. 2) of from 30% to 50%, in particular of up to 40%, of the length l.sub.1 of the projections 7 in the circumferential direction.

[0037] In the exemplary embodiment shown, a transverse groove 12, which runs in the axial direction, ends in front of the circumferential groove 1 at a distance a.sub.1 (FIG. 2), which is ascertained at the tread periphery in the axial direction, of preferably from 2.5 mm to 5.0 mm, has a width B.sub.2 (FIG. 2) of, for example, from 2.0 mm to 5.0 mm on the outer surface of the profile rib 2 and, in the radial direction, a depth T.sub.2 (FIG. 4) which preferably corresponds to the profile depth T.sub.1 within the ground contact patch, is formed next to the projections 7 in the shoulder-side profile rib 2. As shown in FIG. 4 in particular, a channel 13 which is at profile depth T.sub.1 runs between the transverse groove 12 and the path section 11 of the groove path 8. A sipe 14 (also see FIG. 1), which extends in the radial direction, runs between the transverse groove 12 and the circumferential groove 1, has a width of from 0.4 mm to 1.2 mm and is continued in the projection 7 which adjoins the profile rib 2 and includes the projection attachment 9 (FIG. 1), issues over the entire extent of the channel 13 into said channel. The channel 13 has a rounded cross section, a circular cross section in the exemplary embodiment, with a diameter d.sub.1 (FIG. 5) which is selected in such a way 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.

[0038] Both the transverse groove 12, the sipe 14 and also the channel 13 are of symmetrical design with respect to the said plane E.sub.1 (FIG. 2, FIG. 4), and therefore extend in the axial direction or are oriented in the axial direction.

[0039] The invention is not limited to the exemplary embodiment described.

[0040] In particular, the projections 7 can also be formed in central circumferential grooves. The projection attachments 9 are optional.

LIST OF REFERENCE NUMERALS

[0041] 1 . . . Shoulder-side circumferential groove [0042] 2 . . . Shoulder-side profile rib [0043] 3 . . . Central profile rib [0044] 4 . . . Groove base [0045] 4a . . . Groove base section [0046] 4b . . . Rounded transition portion [0047] 5 . . . Groove flank [0048] 6 . . . Groove flank [0049] 7 . . . Projection [0050] 7a . . . Top surface [0051] 7b . . . Projection flank [0052] 7c . . . Projection edge [0053] 7c′ . . . Central edge section [0054] 7c″ . . . End-side edge section [0055] 8 . . . Groove path [0056] 9 . . . Projection attachment [0057] 9a . . . Top surface [0058] 10 . . . Venturi section [0059] 11 . . . Path section [0060] 12 . . . Transverse groove [0061] 13 . . . Channel [0062] 14 . . . Sipe [0063] a.sub.1 . . . Distance [0064] B.sub.1, B.sub.2, b.sub.1 . . . Width [0065] d.sub.1 . . . Diameter [0066] E.sub.1, E.sub.2 . . . Plane [0067] h.sub.1, h.sub.2 . . . Height [0068] l.sub.1 . . . Maximum length [0069] l.sub.2, l.sub.3 . . . Length [0070] P.sub.w . . . Inflection point [0071] T.sub.1 . . . Profile depth [0072] T.sub.2 . . . Depth