Pneumatic vehicle tyre

Abstract

A pneumatic vehicle tire having a tread with profile blocks (4) formed by circumferential or diagonal grooves (1) and by transverse grooves (2), said profile blocks (4) each being provided with at least one sipe (5) that is straight or slightly curved in plan view, extends at least substantially parallel to the transverse grooves (2) and has a width of 0.3 mm to 2.0 mm, wherein the sipe (5) is bounded by two sipe walls (6), and wherein at least one protrusion (8) is provided on each of the otherwise unstructured sipe walls (6). The protrusion (8) formed on one sipe wall (6) is offset in the direction of extent of the sipe (5) with respect to the protrusion (8) formed on the other sipe wall (6), without a mutual overlap.

Claims

1. A pneumatic vehicle tire comprising a tread with profile blocks formed by circumferential or diagonal grooves and by transverse grooves, wherein the profile blocks each have at least one sipe which is straight or slightly curved and extends at least substantially parallel to the transverse grooves, wherein the at least one sipe has a width of 0.3 mm to 2.0 mm, wherein the sipe is bounded by two sipe walls, and wherein at least one protrusion is provided on each of the two sipe walls; wherein the protrusion formed on one of the two sipe walls is offset with respect to the protrusion formed on the other of the two sipe walls, without a mutual overlap; wherein each protrusion provided on each of the two sipe walls has a rounded outer face, and wherein tangents (T.sub.a) through points at the longitudinal ends of each of the protrusions enclose an angle α of 10° to 30° with the sipe wall; wherein the protrusions extend at an angle (β) of up to 20°, relative the radial direction, provided the angle (β) is not 0°; and, wherein each round face of each of the protrusions is curved in the radial direction.

2. The pneumatic vehicle tire as claimed in claim 1, wherein two protrusions are provided on at least one of the two sipe walls, wherein the two protrusions on one sipe wall are offset with respect to the protrusion formed on the other sipe wall, and wherein the protrusions alternate with one another.

3. The pneumatic vehicle tire as claimed in claim 2, wherein two protrusions are provided on each of the two sipe walls, wherein the two protrusions on one sipe wall are offset with respect to the protrusions formed on the other sipe wall, and wherein the protrusions alternate with one another.

4. The pneumatic vehicle tire as claimed in claim 1, wherein three protrusions are provided on at least one of the two sipe walls, wherein the three protrusions on one sipe wall are offset with respect to the protrusion formed on the other sipe wall .

5. The pneumatic vehicle tire as claimed in claim 4, wherein three protrusions are provided on each of the two sipe walls, wherein the three protrusions on one sipe wall are offset with respect to the protrusions formed on the other sipe wall, and wherein the protrusions alternate with one another.

6. The pneumatic vehicle tire as claimed in claim 1, wherein the protrusions are formed in an elongate manner in a radial direction.

7. The pneumatic vehicle tire as claimed in claim 1, wherein the protrusions have an length li of from 3.0 mm to 7.0 mm in the radial direction on the two sipe walls.

8. The pneumatic vehicle tire as claimed in claim 1, wherein the protrusions have a height (h.sub.1), perpendicular to the sipe wall, which is from 20% to 80% of the width of the sipe .

9. The pneumatic vehicle tire as claimed in claim 8, wherein the protrusions have a height (h.sub.1) which is from 30% to 50% of the width of the sipe .

10. The pneumatic vehicle tire as claimed in claim 1, wherein the protrusions have a greatest width (b.sub.2) of from 1.0 mm to 8.0 mm.

11. The pneumatic vehicle tire as claimed in claim 10, wherein the protrusions have a greatest width (b.sub.2) of from 1.0 mm to 4.0 mm.

12. The pneumatic vehicle tire as claimed in claim 1, wherein the protrusions extend at an angle (β) of up to 10°, provided the angle (β) is not 0°.

13. The pneumatic vehicle tire as claimed in claim 1, in one sipe, all of the protrusions are configured in a matching manner.

14. The pneumatic vehicle tire as claimed in 1, wherein the protrusions formed on one sipe wall in one sipe have one or more of different lengths (l.sub.1), different widths (b.sub.1) or different heights (h.sub.1).

15. The pneumatic vehicle tire as claimed in 1, wherein, on one sipe wall in one sipe, at least one protrusion is formed, which differs from at least one protrusion on the other sipe wall in terms of one or more of length (l.sub.1), width (b.sub.1) or height (h.sub.1).

16. The pneumatic vehicle tire as claimed in 1, wherein the protrusions transition into the sipe wall without a bend at least in their end regions located in the radial direction.

17. The pneumatic vehicle tire as claimed in 1, wherein in each case a single sipe, each with at least one protrusion on each sipe wall, is provided substantially centrally in shoulder-side profile blocks of the tread.

Description

(1) Further features, advantages and details of the invention will now be described in more detail on the basis of the drawing, which schematically shows exemplary embodiments of the invention. In the drawings:

(2) FIG. 1 shows a plan view of a tread region of a pneumatic vehicle tire,

(3) FIG. 1a shows a view of a sipe wall with one embodiment variant of the invention,

(4) FIG. 1b shows a view of a sipe wall with a further embodiment variant of the invention,

(5) FIG. 2a shows a section along the line IIa-IIa in FIG. 2,

(6) FIG. 2b shows a section along analogous to FIG. 2a with a variant of the invention, and

(7) FIG. 3 shows a sipe blade of a vulcanization mold in an oblique view.

(8) The invention deals with the configuration of sipes in treads of pneumatic vehicle tires of radial type of construction, in particular pneumatic vehicle tires of passenger cars, vans or light trucks.

(9) The tread region shown by way of example in FIG. 1 is subdivided into profile block rows 3 with profile blocks 4 by circumferential or diagonal grooves 1 and transverse grooves 2. The transverse grooves 2 extend parallel to one another at an acute angle to the circumferential direction, said angle increasing toward the tread edge. Formed approximately centrally in each of the profile blocks 4 is a sipe 5 that extends parallel to the transverse grooves 2 and in a straight or slightly arcuate manner in plan view and is bounded by two mutually opposite sipe walls 6, of which in each case one can be seen in FIGS. 1a and 1b. In other embodiments of the tread, profile blocks with more than one sipe 5 can be provided.

(10) The pneumatic vehicle tire is formed in a known manner by means of a vulcanization mold, which is provided with mold segments or mold parts that provide the tread with its profiling, wherein, to form the sipes 5 in the tread, sipe blades are anchored on the inner side of the mold segments or mold parts. FIG. 3 shows, in a simplified manner, that part of a sipe blade 5′ that forms a sipe in the rubber of the tread. The sipe blade 5′ has an in particular constant thickness d.sub.1 of 0.3 mm to 2.0 mm, preferably up to 0.8 mm, such that the sipes 5 accordingly have a width b.sub.1 (FIG. 1) of 0.3 mm to 2.0 mm, preferably up to 0.8 mm.

(11) The illustrated sipe blade 5′ forms in the tread a sipe 5 having a depth that varies over the sipe profile (FIGS. 1a, 1b), and has a central blade part 5′a and two lateral blade parts 5′b. As FIG. 1a and FIG. 1b show, the sipe 5 and therefore the shown sipe wall 6 have a deep central portion 5a formed by the central blade part 5′a and two shallower lateral portions 5b, adjoining the latter, that are formed by the lateral blade parts 5′b. The central portion 5a extends in a radial direction down to a depth T.sub.1 of for example 6.0 mm to 9.0 mm, and the lateral portions 5b extend in a radial direction down to a depth T.sub.2 that is preferably at most 70% of the depth T.sub.1 and decreases toward the lateral edges of the sipe wall 6.

(12) The sipe blade 5′ has two side faces 6′ that are unstructured apart from recesses 8′, said side faces 6′ forming the sipe walls 6 of the sipe 5 during vulcanization. Formed on each side face 6′, in the central blade part 5′a, are in each case two shallow recesses 8′ that are elongate in a radial direction. The recesses 8′ formed in one side face 6′ are offset in the direction of the longitudinal extent of the sipe blade 5′ with respect to the recesses 8′ formed in the other side face 6′, wherein in each case one recess 8′ in one side face 6′ alternates with a recess 8′ in the other side face 6′ and the recesses 8′ formed in one side face 6′ do not overlap the recesses 8′ that are formed in the other side face 6′. The recesses 8′ are formed conjointly during the production of the sipe blade 5′.

(13) Each recess 8′ has a length l.sub.1′ (FIG. 3) of 3.0 mm to 7.0 mm along a centerline in the direction of its radial extent. Furthermore, each recess 8′ has, at its widest point on the side face 6′, a width b.sub.2′, determined perpendicularly to its centerline, of 1.0 mm to 8.0 mm, in particular up to 4.0 mm, and so, in a preferred embodiment of the recesses 8′, their length l.sub.1′ is greater than their width b.sub.2′.

(14) Each recess 8′ is bounded by a bottom 8′a that is curved in its radial extent, wherein each recess 8′ has its greatest depth t.sub.1′ preferably in its middle with respect to the side face 6′, said depth being 20% to 80%, in particular 30% to 50%, of the thickness d.sub.1 of the sipe blade 5′.

(15) In the embodiment variant shown, the recesses 8′ furthermore have side faces in the form or substantially in the form of circular segments (not indicated in the figures), which bound the recesses 8′ together with the bottom 8′a and accordingly extend between the bottom 8′a and the side face 6′. In an alternative embodiment that is not shown, the recesses 8′ can be embodied as a whole in a rounded manner.

(16) The sipe wall 6 shown by way of example in FIG. 1a is formed with the rear side face 6′ of the sipe blade 5′ and therefore has two protrusions 8 that are elongate in a radial direction and the length l.sub.1 of which, corresponding to the length of the recesses 8′, is 3.0 mm to 7.0 mm. Furthermore, the protrusions 8 have a greatest width b.sub.2 which, corresponding to the width b.sub.2′ of the recesses 8′, is 1.0 mm to 8.0 mm, in particular up to 4.0 mm. Perpendicular to the sipe wall 6, the protrusions 8 have a height h.sub.1, corresponding to the depth t.sub.1′ of the recesses 8′, that is 20% to 80%, in particular 30% to 50%, of the width b.sub.1 of the sipe 5. The outer face of the protrusions 8 is rounded, as shown in FIG. 2a, wherein tangents T.sub.a through points at the longitudinal ends of the protrusions 8 enclose an angle α of 10° to 30° with the sipe wall 6.

(17) FIG. 2b shows an embodiment variant in which a protrusion 8 transitions into the sipe wall 6 without a bend via rounded portions at its ends located in the longitudinal extent.

(18) Corresponding to the positions of the recesses 8′ in the sipe blade 5′, the protrusions 8 formed in one sipe wall 6 are offset in the direction of extent of the sipe 5 with respect to the protrusions 8 formed in the other sipe wall 6 by the recesses 8′, such that the protrusions 8 are formed in regions of the sipe walls 6 that are not located opposite one another.

(19) As the variant in FIG. 1b shows, the protrusions 8 and thus also the protrusions 8 formed in an offset manner on the opposite sipe wall extend at an angle β of up to 20° to the radial direction. A combination of at least one protrusion 8 extending in a radial direction with at least one protrusion 8 extending in an inclined manner to the radial direction per sipe wall 6 is also possible.

(20) All the protrusions 8 on the walls 6 of a sipe 5 can be designed in a matching manner. However, the protrusions 8 formed on one sipe wall 6 can also have different lengths 11 and/or different widths b.sub.1 and/or different heights h.sub.1.

(21) Profile blocks 4 with in each case one sipe 5 designed according to the invention are in particular shoulder blocks, between which transverse grooves 2 extending substantially in a transverse direction are present, as shown in FIG. 1.

LIST OF REFERENCE SIGNS

(22) 1 . . . Circumferential groove 2 . . . Transverse groove 3 . . . Profile block row 4 . . . Profile block 5 . . . Sipe 5′ . . . Sipe blade 5′a, 5′b . . . Blade part 6 . . . Sipe wall 5a . . . Central portion 5b . . . Lateral portion 6′ . . . Side face 8 . . . Protrusion 8′ . . . Recess 8′a . . . Bottom b.sub.1, b.sub.2, b.sub.2′ . . . Width d.sub.1 . . . Thickness h.sub.1 . . . Height l.sub.1, l.sub.1′ . . . Length t.sub.1 . . . Depth T.sub.1, T.sub.2 . . . Depth T.sub.a . . . Tangent α, β . . . Angle