CA3205685A1 - Pneumatic tyre for a vehicle - Google Patents

Abstract

The invention relates to a pneumatic tyre for a vehicle - having a directional tread with at least two profile block rows (1, 2), which are separated by a circumferential channel (5) and are subdivided into profile blocks (7, 9) by transverse channels (6, 8), which open into the circumferential channel (5) and extend parallel to one another in plan view, - wherein the circumferential channel (5) has channel portions (5a) which extend parallel to one another, each separate a profile block (7) of the one profile block row (2) from a profile block (9) of the other profile block row (1) and have a channel base (5a?) and a leading end (5a1), which enters the underlying surface first when the tyre rolls in forward travel (arrow R), and a trailing end (5a2), - wherein the profile blocks (7, 9) each have, at the tread periphery, along the channel portions (5a), a block edge (9c, 13) extending in a straight line in plan view and a block flank (11, 12) starting from the block edge and extending as far as the channel base (5a?) of the respective channel portion (5a), - wherein at least the profile blocks (9) of the one profile block row (1) are provided with sipes (10), which open into the channel portions (5a), have sipe bases (10c) and subdivide each of the block edges (9c) into block edge portions (9c?). The block flanks (11) of the profile blocks (9) which are provided with the sipes (10) opening into the channel portions (5a) form a uniformly stepped structure along the channel portion (5a), which structure is composed of flank surfaces (11a) and transition surfaces (11b), -wherein the flank surfaces (11a) start from the block edge portions (9c?) and extend as far as the channel base (5a?), and - the transition surfaces (11b) extend between the flank surfaces (11a) and from the channel base (5a?) to the sipe base (10c) and are narrower than the flank surfaces (11a), and - wherein, when viewed through a channel portion (5a) in the direction (arrow P) from the leading end (5a1) to the trailing end (5a2), the flank surfaces (11a) obscure the transition surfaces (11b).

Description

Description Title of the Invention Pneumatic tyre for a vehicle The invention relates to a pneumatic tyre for a vehicle - having a directional tread with at least two profile block rows, which are separated by a circumferential channel and are subdivided into profile blocks by transverse channels, which open into the circumferential channel and extend parallel to one another in plan view, - wherein the circumferential channel has channel portions which extend parallel to one another, each separate a profile block of the one profile block row from a profile block of the other profile block row and have a channel base and a leading end, which enters the underlying surface first when the tyre rolls in forward travel, and a trailing end, - wherein the profile blocks each have, at the tread periphery, along the channel portions, a block edge extending in a straight line in plan view and a block flank starting from the block edge and extending as far as the channel base of the respective channel portion.
Such a pneumatic tyre for a vehicle is known for example from DE 10 2015 221 118 Al. In the exemplary embodiment described, the tread has transverse channels which extend in a V-shape over the width of the tread and separate profile blocks belonging to two shoulder-side and two central profile block rows from one another. The shoulder-side profile block rows are separated from the central profile block rows by circumferential channels which, in plan view, are inclined with respect to the circumferential direction and have channel portions which extend parallel to one another and each separate a profile block of a shoulder-side profile block row from a profile block of the central profile block row.
The profile blocks of both profile block rows are provided with sipes, wherein the sipes formed in the profile blocks of the shoulder-side profile block row extend parallel to the transverse channels in plan view, open into the channel portions of the circumferential channel and give the respective profile block block segments.
Furthermore, the profile blocks are each provided with a spike, which is

2 surrounded by depressions formed in the profile block and serving as ice reservoirs.
It is known that the braking properties of pneumatic tyres for vehicles on snow are affected by a number of mechanisms or effects. These effects include rubber-snow friction, snow-snow friction (snow accumulated in channels or sipes improves grip) and channel and sipe edges acting as gripping edges. With increasing tread wear, there is a risk that the snow grip properties, in particular the braking properties on snow, will decline. Corresponding countermeasures, such as circumferential channels extending in a pronounced zig-zag or undulating manner, reduce the water drainage capacity of the tread.
It is therefore the underlying object of the invention, in the case of a pneumatic tyre for a vehicle of the type stated at the outset, to keep the braking properties on snow at a high level throughout the wearing of the tread, while at the same time maintaining a good water drainage capacity.
According to the invention, the stated object is achieved by virtue of the fact that - the block flanks of the profile blocks which are provided with the sipes opening into the channel portions form a uniformly stepped structure along the channel portion, which structure is composed of flank surfaces and transition surfaces, - wherein the flank surfaces start from the block edge portions and extend as far as the channel base, and - the transition surfaces extend between the flank surfaces and from the channel base to the sipe base and are narrower than the flank surfaces, and - wherein, when viewed through a channel portion in the direction from the leading end to the trailing end, the flank surfaces obscure the transition surfaces.
The transition surfaces extending from the channel base to the sipe base promote the opening behavior of the sipes in the region of their edge-side sipe portions, which open into the channel portions, when driving on snow, thus improving the effect of the sipe edges as gripping edges in this region. As the wear of the profile

3 blocks progresses, the edge-side sipe portions opening into the channel portions disappear, resulting in the appearance in this region of additional edges on the tread periphery, which is "offset" by the wear, at the radially outer ends of the transition surfaces, the additional edges making the block edges located on the channel portions somewhat longer overall. At the same time, the rigidity of the profile blocks increases with increasing tread wear. The bending capacity of the profile blocks, which decreases with the increasing rigidity of the profile blocks, and the associated influence on the effect of the block edges as gripping edges, is compensated for or at least largely balanced out by the aforementioned additional edges forming on the transition surfaces, ensuring that good snow grip, particularly under braking load, is maintained. Since, when viewed through a channel portion in the direction from the leading end to the trailing end, the flank surfaces obscure the transition surfaces, the influence of the stepped structure on the water drainage capacity in the channel portions is extremely small or negligible and, in particular, a largely turbulence-free or low-turbulence water flow through the circumferential channel is ensured, and therefore a high water drainage capacity is maintained.
According to one preferred embodiment, the channel portions are inclined with respect to the circumferential direction in such a way that the leading end of each channel portion is closer to the tyre equatorial plane than the trailing end.
When driving on a wet roadway, this contributes to effective drainage of water from the region of the ground contact area and is thus advantageous for the water drainage capacity.
The transition surfaces of the block flanks, which form the uniformly stepped structure, preferably have a width at their widest point of 0.3 mm to 1.0 mm, in particular of 0.5 mm to 0.8 mm. The transition surfaces are therefore correspondingly narrow, and this is of additional advantage for the water drainage behavior in the channel portions.
It is furthermore advantageous if the transition surfaces of the block flanks, which form the uniformly stepped structure, have a radially outer boundary edge, which

4 adjoins the sipe base and has a length of, in particular, at most 0.3 mm. Such a boundary edge promotes the opening behavior of the edge-side sipe portions opening into the channel portions in the case of a tyre which is new or has little wear. This is attributable to the fact that the snow which accumulates in the edge-side sipe portions when driving on snow produces a force at this edge which assists the opening, i.e. the folding back, of the edge-side sipe portions upon ground contact. This improves the effect of the sipe edges as gripping edges.
According to one preferred embodiment, the transition surfaces of the block flanks, which form the uniformly stepped structure, become narrower, in particular continuously narrower, in the direction of the respective sipe base, at least over a radially outer surface portion. With increasing tread wear, the already mentioned additional edge which forms at the radially outer end of the transition surfaces becomes continuously longer and in this way balances out the lower gripping effect of the sipe edges which is associated with the decreasing bending capacity of the profile blocks, or contributes to the maintenance of good braking properties on snow.
In the case of the last-mentioned embodiment, it is advantageous if the transition surfaces of the block flanks, which form the uniformly stepped structure, are each composed in the radial direction of the radially outer surface portion and a radially inner surface portion extending in the form of a circular arc in the radial direction, wherein the radially outer surface portion and the radially inner surface portion adjoin one another in the radial direction at a depth of 50% to 95%, in particular of 70% to 80%, of the profile depth.
According to another preferred embodiment, the transition surfaces of the block flanks, which form the uniformly stepped structure, are set transversely or obliquely with respect to the direction of extent of the channel portions when viewed in plan view.
Another preferred embodiment is characterized in that the flank surfaces of the block flanks, which form the uniformly stepped structure, are composed in the radial direction of a radially outer surface portion and a radially inner surface portion, wherein, when viewed in cross section perpendicularly to the block edge portion, the radially outer surface portion extends in a straight line and at an angle of 0 to 70, in particular of 1 to 50, to the radial direction, wherein the angle

5 increases continuously in the direction of the trailing end of the channel portion, in particular by up to 2 , over the extent of the block edge portion. This measure is favorable in terms of the water drainage capacity.
Another embodiment which is favorable in respect of the water drainage capacity is characterized in that only the block flanks of the profile blocks of the one profile block row form the uniformly stepped structure, and the block flanks of the profile blocks of the other profile block row are unstructured surfaces.
It is advantageous in this embodiment if the profile block row having the profile blocks, the block flanks of which form the uniformly stepped structure, is located further to the outside of the tread than the other profile block row.
It is of further advantage in this embodiment if the profile block row having those profile blocks, the block flanks of which form the uniformly stepped structure, is a shoulder-side profile block row.
It is furthermore advantageous in this embodiment if, when viewed in cross section perpendicularly to the center line of the channel portion, the block flanks which are unstructured surfaces extend at an angle, in particular a constant angle, of 2 to 10 , preferably of 4 to 8 , to the radial direction.
Another preferred embodiment which is favorable, in particular, for grip on snow, is characterized in that, when viewed in plan view and in relation to a center line, the channel portions of the circumferential channel each extend at an angle of 2 to 7 , in particular at most 50, to the circumferential direction.

6 According to another embodiment which is likewise favorable in respect of grip on snow, the circumferential channel has a reduced "lookthrough" or no "lookthrough"
when viewed in cross section.
In the case of a tyre which is new or has little wear, it is favorable for the braking properties on snow if the sipes each have an edge-side sipe portion which opens into the channel portion and has a depth in the radial direction of 20% to 40%, in particular of 25% to 35%, of the profile depth.
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:
Figure 1 shows a simplified plan view of a circumferential portion, developed into the plane, of a tread of a pneumatic tyre for a vehicle with a variant embodiment of the invention, Figure 2 shows an enlarged plan view of two profile blocks belonging to the tread, Figure 3 shows a section along the line III-Ill in figure 2, Figure 4 shows a simplified oblique view in accordance with the viewing direction indicated in figure 2 by an arrow S4, and Figure 5 shows a further-enlarged oblique view in accordance with the viewing direction indicated in figure 2 by an arrow S5.
Pneumatic tyres for vehicles which are designed according to the invention are tyres for motor vehicles, in particular for multitrack vehicles, and preferably tyres of radial type of construction for passenger motor vehicles, vans or light trucks (permitted total weight 5 7.5 t), wherein the tyres are provided for use under wintry driving conditions.

7 Figure 1 shows a simplified plan view of a circumferential portion of a tread of a pneumatic tyre for a vehicle. The tyre equatorial plane is indicated by a dashed line A-A and the lateral edges of the ground contact area of the tread are indicated by dashed lines I. The ground contact area corresponds to the statically determined footprint according to E.T.R.T.O. standards (load at 70% of the maximum load capacity at an internal pressure of 85% according to E.T.R.T.O.
standard).
The tread has two shoulder-side profile block rows 1, two central profile block rows 2 formed adjacent thereto, and a central profile rib 3, is symmetrical with respect to the tyre equatorial plane (line A-A) in the exemplary embodiment shown, and is furthermore provided with directional profiling, wherein the pneumatic tyre for a vehicle is to be mounted on the vehicle in such a way that it has the rolling direction indicated by the arrow R in forward travel.
The central profile block rows 2 are each separated from the central profile rib 3 by a central circumferential channel 4, which extends in a straight line in plan view, and from the respectively adjacent shoulder-side profile block row 1 by a shoulder-side circumferential channel 5, which extends in a sawtooth shape in plan view.
The circumferential channels 4, 5 are formed to the respectively provided profile depth TP (figure 3, shown for a shoulder-side circumferential channel 5), which is typically 6.5 mm to 10.0 mm for the preferred tyre type.
The central profile block rows 2 are each provided with central transverse channels 6, which extend parallel to one another in plan view and in an arc and which end within the profile block rows 2 on the inside of the tread, open into the respective shoulder-side circumferential channel 5 on the outside of the tread and provide the central profile block rows 2 with substantially parallelogram-shaped central profile blocks 7 in plan view. The orientation of the transverse channels 6 is such that they enter the underlying surface first with their ends on the inside of the tread.

8 The shoulder-side profile block rows 1 are each provided with shoulder-side transverse channels 8 which extend parallel to one another in plan view and which open into the respective shoulder-side circumferential channel 5, separate shoulder-side profile blocks 9 from one another and, in plan view, extend in a slightly arcuate manner and, in relation to channel center lines mQR following the channel path in plan view, extend at an angle a (figure 2, parts of two transverse channels 8 can be seen) of 2 to 25 , in particular of 50 to 20 , to the axial direction, wherein the angle a decreases continuously in the direction of the tread shoulder.
The shoulder-side transverse channels 8 extend at least substantially as a continuation of the central transverse channels 6, the transverse channels 6, extending overall in a V-shape over the width of the tread. As a result of the V-shaped path of the transverse channels 6, 8, each shoulder-side circumferential channel 5 has a multiplicity of channel portions 5a, which each separate a shoulder-side profile block 9 from a central profile block 7, and therefore extend as far as the respective transverse channels 6, 8 and have a channel base 5a`
which extends at the profile depth TP (figure 3).
The further development of the central profile blocks 7, the shoulder-side profile blocks 9 and the channel portions 5a is explained below with reference to two adjacent profile blocks 7, 9 and the associated channel portion 5a with the aid of figures 2 to 5. Figure 2 shows an enlarged and detailed illustration of a shoulder-side profile block 9 as well as the central profile block 7 formed adjacent thereto.
Figure 3 shows the section along the line III-Ill in figure 2, figure 4 shows a view according to the arrow S4 in figure 2 in a simplified illustration, and figure 5 shows a view according to the arrow S5 in figure 2.
As shown in figure 2, the channel portion 5a, when viewed in plan view and in relation to a center line mRA, extends in a straight line as well as at an angle 13 of 2 to 7 , in particular at most 5 , to the circumferential direction and, at the tread periphery, has a width bRA of 6.0 mm to 13.0 mm, determined perpendicularly to the center line mRA. The width bRA and the angle 13 of the channel portion 5a are

9 matched to one another in such a way that the shoulder-side circumferential channels 5 have no "lookthrough" or a reduced "lookthrough", that is to say that, when viewed in the cross section oriented in the axial direction, no view or a reduced view through the shoulder-side circumferential channels 5 is possible (cf.
figure 1). The channel portion 5a has a leading end 5a1, which enters the underlying surface first when the tyre rolls in forward travel, and a trailing end 5a2 and is inclined with respect to the circumferential direction in such a way that - in relation to the center line nnRA - the leading end 5a1 is closer to the tyre equatorial plane than the trailing end 5a2 (cf. figure 1).
The central profile block 7 is delimited with respect to the channel portion 5a by a block flank 12 (cf. figure 3), which extends as far as the channel base 5a`, starts from a block edge 13 and is an unstructured surface. The block flank 12 is accordingly free of unevenness, such as, for example, projections or channels.
As figure 3 shows, the block flank 12, when viewed in cross section perpendicularly to the center line mRA, appears as a straight line which encloses an angle c, in particular a constant angle, of 2 to 100, in particular of 4 to 8 , with the radial direction.
The shoulder-side profile block 9 has block edges 9a, 9b, 9c at the tread periphery. The block edges 9a, 9b are formed on the adjacent shoulder-side transverse channels 8, block edge 9a entering the underlying surface before block edge 9b when the tyre rolls in forward travel (arrow R). Block edge 9c is formed along the channel portion 5a and, when viewed in plan view, extends in a straight line and at an angle y of 2 to 7 , in particular at most 5 , to the circumferential direction, wherein the angle y coincides with the angle 13 of the channel portion 5a or deviates from this by, in particular, 2 .
The shoulder-side profile block 9 is furthermore traversed by a number of sipes 10, which are at least substantially uniformly distributed over the circumferential extent of the profile block 9 and which, when viewed in plan view, as a whole extend slightly arcuately and parallel to the channel center lines mQR of the transverse channels 8, extend beyond the lateral edge of the ground contact area (line I), open into the channel portion 5a and have a width of 0.4 mm to 1.2 mm, in particular of at most 0.8 mm, and, in the radial direction, at their lowest point, a depth of 75% to 100%, in particular of at most 90%, of the profile depth TP
(figure 3). The sipes 10 subdivide the shoulder-side profile block 9 into block segments 5 9d, interrupt the block edge 9c formed along the channel portion 5a and impart to the block edge block edge portions 9c`, which each belong to one of the block segments 9d. Furthermore, the sipes 10 each have a sipe base 10c (figure 5) and, in the exemplary embodiment shown, a sipe main portion 10a, which extends in a sawtooth shape in plan view, and a sipe edge portion 10b, which opens into the

10 channel portion 5a and extends in a straight line or in a hardly noticeably curved manner in plan view, and which, according to figure 5, has a depth tb, determined in the radial direction with respect to the block edge 9c or the block edge portions 9c`, of 20% to 40%, in particular of 25% to 35%, of the profile depth TP
(figure 3) at its opening located on the channel portion 5a. The number of sipes 10 is matched, in particular in a known manner, to the circumferential length of the shoulder-side profile block 9, the shoulder-side profile blocks 9 being provided, in particular, with two, three and four sipes 10.
As further shown in figure 2, the shoulder-side profile block 9 is delimited with respect to the channel portion 5a by a block flank 11, which starts from the block edge 9c and extends as far as the channel base 5a` (figure 3) and which forms a uniformly stepped structure (cf. figure 4, in which the sipes 10 are not shown) that extends over its circumferential extent and is matched to the block segments 9d.
When viewed over the circumferential extent of the block flank 11, the uniformly stepped structure of the block flank 11 is composed of flank surfaces lla assigned to the block segments 9d and of transition surfaces llb set transversely or obliquely with respect to the channel center line mRA, wherein in each case a flank surface 11 a alternately follows a transition surface 11 b. As shown, in particular, in figures 3 to 5 in combination with one another, the flank surfaces 11a each start from a block edge portion 9c` (figure 4, figure 5) and extend as far as the channel base 5a` (figure 3). The transition surfaces llb extend between the flank surfaces lla (figure 4, figure 5) and extend between the channel base 5a`

11 (figure 2, figure 3) and the sipe base 10c (figure 5), and therefore end at the aforementioned depth lb at the sipe edge portions 10b (figure 5).
The stepped profile of the block flank 11 is embodied in such a way that, when seen through the channel portion 5a with the viewing direction corresponding to the angle 13 of the center line mRA and from the leading end 5a1 to the trailing end 5a2 (indicated by the arrow P in figure 2), the flank surfaces 11 a obscure the transition surfaces 11 b. In this respect, the transition surfaces llb are "concealed"
by the flank surfaces ha.
According to figure 3, each flank surface 11a, when viewed in cross section perpendicularly to the block edge portion 9c` (cf. position of section line III-Ill in figure 2), is composed of a radially outer surface portion 11a` and a radially inner surface portion lla". The radially outer surface portion 11 a', when viewed in cross section perpendicularly to the block edge portion 9d, extends in a straight line and at an angle 6 of 0 to 70, in particular of 1 to 50, to the radial direction, wherein the angle 6 increases by, in particular, up to 2 over the extent of the block edge portion 9c` in the direction of the trailing end 5a2 (figure 2) of the channel portion 5a, thereby "giving rise to" the transition surfaces 11 b (figure 2). The increase in the angle 6 takes place, in particular, continuously, i.e. uniformly. The radially outer surface portion 11 a' is therefore a surface which twists over the extent of the block edge portion 9c`. The radially inner surface portion ha", when viewed in cross section perpendicularly to the block edge portion 9c`, extends in a circularly curved manner and merges without kinking into the radially outer surface portion II a' and the channel base 5a`. The radially outer surface portion 11 a and the radially inner surface portion 11a" adjoin one another at a depth ti, determined in the radial direction, of 50% to 95%, in particular of 70% to 80%, of the profile depth TP.
As figure 4 and figure 5 show, each transition surface llb is composed in the radial direction of a radially outer surface portion 11 b' and a radially inner surface portion 11b". The radially inner surface portion 11b" of the transition surface llb extends between the radially inner surface portions 11a" of the adjoining flank

12 surface 11a, has a shape in the form of a circular arc in the radial direction (see especially figure 4) - corresponding to the shape of the radially inner surface portions 11 a" - and furthermore has a constant width bF (figure 5) of 0.3 mm to 1.0 mm, in particular of 0.5 mm to 0.8 mm. According to figure 5, the radially outer surface portion 11 b of the transition surface 11 b extends between the radially outer surface portions 11 a' of the respectively adjoining flank surfaces 11 a and becomes narrower, in particular continuously narrower, starting from the radially inner surface portion 11b", at which it likewise has the width bF, in the direction of the sipe edge portion 10b, and ends at the depth tb. Furthermore, the radially outer surface portion lib' has, at the depth tb, a radially outer boundary edge 14, which adjoins the sipe base 10c and has a length of, in particular, at most 0.3 mm.
The radially outer surface portion 11 b' is therefore a substantially triangular surface elongated in the radial direction. Analogously to surface portions 11a', 11 a", the radially outer surface portion 11 b' and the radially inner surface portion 11b" adjoin one another at the already mentioned depth tl.
The invention is not limited to the exemplary embodiment described.
In particular, the tread has at least two profile block rows, wherein the profile blocks of one profile block row are provided with the uniformly stepped structure.
The inclination of the channel portions of the circumferential channel which separates the at least two profile block rows from one another can differ from the embodiment described. The radially outer surface portion of the transition surfaces can run out at the sipe base, with the result that the latter does not have a radially outer boundary edge.

13 List of reference signs 1 Shoulder-side profile block row 2 Central profile block row 3 Central profile rib 4 Central circumferential channel 5 Shoulder-side circumferential channel 5a Channel portion 5a` Channel base 5a1 Leading end 5a2 Trailing end 6 Central transverse channel 7 Central profile block 8 Shoulder-side transverse channel 9 Shoulder-side profile block 9a, 9b, 9c Block edge 9c` Block edge portion 9d Block segment 10 Sipe 10a Sipe main portion 10b Sipe edge portion 10c Sipe base 11 Block flank 11a Flank surface 11a` Radially outer surface portion 11a" Radially inner surface portion 11b Transition surface 1113' Radially outer surface portion 11b" Radially inner surface portion 12 Block flank 13 Block edge

14 Boundary edge A-A Line (tyre equatorial plane) bF, bRA Width I Line (lateral edge of the ground contact area) IL, IM, IK Circumferential length L, M, K Pitch mQR Channel center line mRA Center line P Arrow (viewing direction) R Arrow (rolling direction) S4, S5 Arrow (viewing direction) tb, t1 Depth TP Profile depth a, 13, y, 6, E Angle

Claims (15)

Patent claims

1. A pneumatic tyre for a vehicle - having a directional tread with at least two profile block rows (1, 2), which are separated by a circumferential channel (5) and are subdivided into profile blocks (7, 9) by transverse channels (6, 8), which open into the circumferential channel (5) and extend parallel to one another in plan view, - wherein the circumferential channel (5) has channel portions (5a) which extend parallel to one another, each separate a profile block (7) of the one profile block row (2) from a profile block (9) of the other profile block row (1) and have a channel base (5a) and a leading end (5a1), which enters the underlying surface first when the tyre rolls in forward travel (arrow R), and a trailing end (5a2), - wherein the profile blocks (7, 9) each have, at the tread periphery, along the channel portions (5a), a block edge (9c, 13) extending in a straight line in plan view and a block flank (11, 12) starting from the block edge and extending as far as the channel base (5a`) of the respective channel portion (5a), - wherein at least the profile blocks (9) of the one profile block row (1) are provided with sipes (10), which open into the channel portions (5a), have sipe bases (10c) and subdivide each of the block edges (9c) into block edge portions (90, characterized in that - the block flanks (11) of the profile blocks (9) which are provided with the sipes (10) opening into the channel portions (5a) form a uniformly stepped structure along the channel portion (5a), which structure is composed of flank surfaces (11a) and transition surfaces (11 b), - wherein the flank surfaces (11a) start from the block edge portions (90 and extend as far as the channel base (50, and - the transition surfaces (11b) extend between the flank surfaces (11a) and from the channel base (5a`) to the sipe base (10c) and are narrower than the flank surfaces (11a), and - wherein, when viewed through a channel portion (5a) in the direction (arrow P) from the leading end (5a1) to the trailing end (5a2), the flank surfaces (11a) obscure the transition surfaces (11b).

2. The pneumatic tyre for a vehicle as claimed in claim 1, characterized in that the channel portions (5a) are inclined with respect to the circumferential direction in such a way that the leading end (5a1) of each channel portion (5a) is closer to the tyre equatorial plane (line A-A) than the trailing end (5a2).

3. The pneumatic tyre for a vehicle as claimed in claim 1 or 2, characterized in that the transition surfaces (11b) of the block flanks (11), which form the uniformly stepped structure, have a width (bF) at their widest point of 0.3 mm to 1.0 mm, in particular of 0.5 mm to 0.8 mm.

4. The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 3, characterized in that the transition surfaces (11b) of the block flanks (11), which form the uniformly stepped structure, have a radially outer boundary edge (14), which adjoins the sipe base (10c) and has a length of, in particular, at most 0.3 mm.

5. The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 4, characterized in that the transition surfaces (11b) of the block flanks (11), which form the uniformly stepped structure, become narrower, in particular continuously narrower, in the direction of the respective sipe base (10c), at least over a radially outer surface portion (11b`).

6. The pneumatic tyre for a vehicle as claimed in claim 5, characterized in that the transition surfaces (11 b) of the block flanks (11), which form the uniformly stepped structure, are each composed in the radial direction of the radially outer surface portion (110 and a radially inner surface portion (11 b") extending in the form of a circular arc in the radial direction, wherein the radially outer surface portion (110 and the radially inner surface portion (11b") adjoin one another in the radial direction at a depth (ti) of 50% to 95%, in particular of 70% to 80%, of the profile depth (Tp).

7. The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 6, characterized in that the transition surfaces (11b) of the block flanks (11), which form the uniformly stepped structure, are set transversely or obliquely with respect to the direction of extent of the channel portions (5a) when viewed in plan view.

8. The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 7, characterized in that the flank surfaces (11a) of the block flanks (11), which form the uniformly stepped structure, are composed in the radial direction of a radially outer surface portion (110 and a radially inner surface portion (11a"), wherein, when viewed in cross section perpendicularly to the block edge portion (90, the radially outer surface portion (11 a') extends in a straight line and at an angle (6) of 00 to 7 , in particular of 10 to 5 , to the radial direction, wherein the angle (6) increases continuously in the direction of the trailing end (5a2) of the channel portion (5a), in particular by up to 2 , over the extent of the block edge portion (94

9. The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 8, characterized in that only the block flanks (11) of the profile blocks (9) of the one profile block row (1) form the uniformly stepped structure, and the block flanks (12) of the profile blocks (7) of the other profile block row (2) are unstructured surfaces.

10.The pneumatic tyre for a vehicle as claimed in claim 9, characterized in that the profile block row (1) having the profile blocks (9), the block flanks (11) of which form the uniformly stepped structure, is located further to the outside of the tread than the other profile block row (2).

11.The pneumatic tyre for a vehicle as claimed in claim 9 or 10, characterized in that the profile block row (1) having those profile blocks (9), the block flanks (11) of which form the uniformly stepped structure, is a shoulder-side profile block row (1).

12.The pneumatic tyre for a vehicle as claimed in any one of claims 9 to 11, characterized in that, when viewed in cross section perpendicularly to the center line (mRA) of the channel portion (5a), the block flanks (12) which are unstructured suifaces extend at an angle (E), in particular a constant angle, of 2 to 10 , preferably of 4 to 8 , to the radial direction.

13.The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 11, characterized in that, when viewed in plan view and in relation to a center line (mRA), the channel portions (5a) of the circumferential channel (5) each extend at an angle (8) of 2 to 7 , in particular at most 5 , to the circumferential direction.

14.The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 13, characterized in that the circumferential channel (5) has a reduced "lookthrough" or no "lookthrough" when viewed in cross section.

15.The pneumatic tyre for a vehicle as claimed in any one of claims 1 to 14, characterized in that the sipes (10) each have an edge-side sipe portion (10b) which opens into the channel portion (5a) and has a depth (tb) in the radial direction of 20% to 40%, in particular of 25% to 35%, of the profile depth (Tp).