Pneumatic tyre for a vehicle
Patent Information
- Application Number
- EP2023711667
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-04-25
- Filing Date
- 2023-03-06
- Publication Date
- 2025-03-05
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] Pneumatic vehicle tires
[0003] The invention relates to a pneumatic vehicle tire with a tread and sidewalls, wherein the tread has at least one shoulder-side profile rib with an inner section located within the ground contact area and a shoulder section located outside the ground contact area with a half adjacent to the lateral edge of the ground contact area and a half adjacent to the sidewall, wherein elongated, rectangular or rectangular depressions are formed in the shoulder section, which extend to the circumferential direction at an angle which deviates from 90° by up to 10°.
[0004] Such a pneumatic vehicle tire is known, for example, from
[0005] DE 102018 119 892 A1. The pneumatic vehicle tire has a tread with two central tread ribs and two shoulder-side tread ribs, wherein the tread ribs are separated from each other by circumferential grooves. The central tread ribs are provided with blind grooves that open into the adjacent circumferential grooves, each of which is opposed by incisions ending on one side in the central tread rib. The shoulder-side tread ribs are structured into tread blocks by transverse grooves, wherein each tread block is provided with incision-like depressions running transversely to the circumferential direction in the shoulder section outside the ground contact area. The tire is intended to enable good steering stability on icy and snowy road surfaces and to exhibit even wear behavior in the area of the central tread ribs.
[0006] It is generally known that depressions formed in the shoulder section (so-called off-shoulder area) of shoulder-side tread ribs can help improve traction when driving on soft surfaces, particularly on snow, slush or mud. Furthermore, it is known that such depressions can have a beneficial effect on air flow around the tire and consequently on vehicle aerodynamics and thus driving safety. In this context, what is known as boundary layer separation plays a crucial role. Boundary layer separation is a fluid mechanics effect which causes a flow to not follow the contour of a body around which it is flowing. In particular, a turbulent area forms between the laminar main flow and the body contour, which is known as “dead water” or “wake”.Wake is the area behind the body being flowed around, in which the flow velocity is noticeably influenced by the body. Boundary layer separation causes flow separation, which leads to the formation of backflow areas that increase flow resistance. The flow separation that occurs during driving on motor vehicles therefore has an adverse effect on vehicle aerodynamics. The invention is therefore based on the object of significantly improving the effects of the depressions on vehicle aerodynamics in a pneumatic vehicle tire of the type mentioned above, while still maintaining good traction on soft surfaces.The stated object is achieved according to the invention in that the depressions are arranged in groups, each group comprising at least three depressions which follow one another in the circumferential direction, run parallel to one another and exclusively in the half of the shoulder section adjacent to the sidewall, said depressions having a depth of 0.3 mm to 1.0 mm and a width of 0.4 mm to 2.0 mm, the depressions arranged in the same group having mutual distances in the circumferential direction which are smaller than the distances determined as the smallest distances between the groups following one another in the circumferential direction. When driving, the depressions cause turbulence in the air flowing past the rotating tire, the turbulence changing the boundary layer separation in such a way that the dead water zone is reduced, thereby advantageously influencing the aerodynamic properties of the vehicle.The grouping and appropriate dimensioning of the dimples maintains high lateral rigidity in the shoulder section, so that the edges provided by the dimples act as particularly effective gripping edges when driving on soft surfaces. This ensures good traction on soft surfaces.
[0007] According to a preferred embodiment, the groups each include up to five recesses. Groups with such a limited number of recesses are advantageous with regard to transverse stiffness in the shoulder section.
[0008] Preferably, groups are provided, each of which includes exactly three recesses. These groups allow a particularly favorable compromise to be achieved between the beneficial effects of the recesses on vehicle aerodynamics and traction on soft surfaces.
[0009] According to a further preferred embodiment, the recesses have a length of 3.0 mm to 7.5 mm, which contributes to maintaining high transverse rigidity.
[0010] An advantageous development of the latter preferred embodiment is characterized in that groups are provided in which the length of the central depression(s) is at least 2.0 mm greater than the length of each edge depression. This measure has a positive effect on the turbulence generated by the depressions in the air flowing past the rotating tire during driving, and is therefore further advantageous for vehicle aerodynamics, with the influence of the depressions on the lateral stiffness in the shoulder section being particularly minimal.
[0011] In the aforementioned advantageous development, it is advantageous if the central recess(es) project beyond each edge recess on the side facing away from the sidewall. This measure is also particularly beneficial for the transverse rigidity in the shoulder section.
[0012] A further preferred embodiment provides that the mutual spacing between the recesses arranged in the same group is 0.5 mm to 2.0 mm. Due to the rubber ridges formed between the recesses in this way, the recesses have edges at the level of the shoulder flank that are particularly advantageous for traction on soft surfaces.
[0013] A further preferred embodiment is characterized in that groups are provided in which the width of the central depression(s) is 150% to 250%, in particular 180% to 220%, of the width of each edge depression, with the widths of the edge depressions preferably matching. The turbulence caused by such depressions in the passing air is particularly favorable for the aerodynamic properties.
[0014] According to a further preferred embodiment, the recesses have a preferably identical distance of 1.0 mm to 2.0 mm from the end of the half of the shoulder section adjacent to the side wall, measured transversely to the circumferential direction. This is also beneficial for the effect of the edges of the recesses and therefore has a beneficial effect on traction on soft surfaces.
[0015] The angle at which the recesses extend to the circumferential direction preferably deviates from 90° by up to 5°. The inclination of the corresponding edges, which is close to 90°, is an additional advantage for traction on soft surfaces.
[0016] A further preferred embodiment is characterized in that the shoulder-side tread rib is provided with transverse grooves, with the groups in which the recesses are arranged each located in a separate circumferential section of the shoulder-side tread rib, extending between two transverse grooves and reaching to the sidewall. This additionally contributes to high rigidity in the shoulder section and is thus advantageous for traction properties on soft surfaces.
[0017] In the last-mentioned preferred embodiment, it is advantageous if, in the half of the shoulder section adjacent to the side wall, at every or every second transverse groove, an elongated, rectangular or rectangular further depression is formed which adjoins the transverse groove and runs at an angle deviating from 90° by up to 10° to the circumferential direction, with a depth of 0.3 mm to 1.0 mm, in particular from 0.4 mm to 0.6 mm, and a width of 0.4 mm to 2.0 mm, in particular from 0.6 mm to 1.0 mm, wherein the further depression preferably runs parallel to the depressions arranged in groups and in particular has a depression edge which adjoins one of the groove edges of the transverse groove tangentially. The further depression supports the effect of the depressions arranged in groups.
[0018] Furthermore, it is preferred to provide groups in which the recesses are symmetrical with respect to a central plane perpendicular to the shoulder flank, extending longitudinally along the recesses and centrally through the group. Such symmetrical groups ensure an at least largely uniform influence on stiffness and are therefore favorable for traction properties on soft surfaces.
[0019] Preferably, the depth of the recesses is 0.4 mm to 0.6 mm. According to another preferred embodiment, the distances determined as the smallest distances between the circumferentially successive groups are 3.0 mm to 10.0 mm. This also contributes to maintaining high rigidity in the shoulder section.
[0020] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows an embodiment of the invention.
[0021] Fig. 1 is a plan view of a circumferential section of a shoulder-side profile rib of a tread of a pneumatic vehicle tire developed in the plane with an embodiment variant of the invention,
[0022] Fig. 2 is an enlarged plan view of the detail Z2 of Fig. 1,
[0023] Fig. 3 is a section along the line III-III of Fig. 2,
[0024] Fig. 4 is a section along the line IV-IV of Fig. 2 and
[0025] Fig. 5 is a view according to the viewing direction indicated in Fig. 2 by the arrow S5, taking into account the tire curvature.
[0026] Pneumatic vehicle tires designed according to the invention are tires for motor vehicles, in particular for multi-track motor vehicles, and preferably tires of radial design for passenger cars, vans or light trucks (small vans with GVW < 3.51, light trucks with GVW < 7.51).
[0027] Fig. 1 shows a plan view of a circumferential section of a shoulder-side profile rib 1 of a tread of a pneumatic vehicle tire. The lateral edge of the ground contact patch of the tread is indicated by a dashed line L, wherein the ground contact patch corresponds to the statically determined footprint according to ETRTO standards (load at 70% of the maximum load capacity at an internal pressure of 85% according to the ETRTO standard). The tread has a further shoulder-side profile rib in its second shoulder (not shown), the design of which preferably differs from that of the shoulder-side profile rib 1, so that the tread has an asymmetrical shape with respect to the tire equatorial plane.
[0028] The shoulder-side profile rib 1 is delimited on the inside of the tread by a shoulder-side circumferential groove 2 which, in the embodiment shown, runs straight in plan view and which is designed in the radial direction to the respectively intended profile depth, which for the preferred tire type is usually 6.5 mm to 13.0 mm.
[0029] The shoulder-side tread rib 1 has an inner section 3 located within the ground contact area with an outer surface 3a located in the tread periphery and a shoulder section 4 located outside the ground contact area and running to the sidewall (not shown) with a shoulder flank 4a located in the tread periphery and tangentially adjoining the outer surface 3a (see Fig. 5) and is provided over its circumferential extent with a multiplicity of transverse grooves 5 ending within the shoulder-side tread rib 1, which transverse grooves 5 each run in sections in the inner section 3 and in sections in the shoulder section 4 and - viewed in plan view - preferably parallel to one another and to the axial direction at an angle of up to 30°.Transverse grooves 5 which are directly consecutive in the circumferential direction have distances aQR of 15.0 mm to 45.0 mm, in particular of 20.0 mm to 35.0 mm, determined from one another on the outer surface 3a in the circumferential direction as the smallest possible distances.
[0030] Each transverse groove 5 has two groove edges 5a, each running in sections on the outer surface 3a and in sections on the shoulder flank 4a, is delimited by a groove base 5b, two groove flanks 5c and on the inside of the tread by an end flank 5d (Fig. 3), furthermore has a maximum depth tQR (Fig. 3) determined within the inner section 3 in the radial direction of 70% to 100% of the profile depth and a width boR of 3.0 mm to 6.0 mm determined at the level of the outer surface 3a as the smallest possible distance between the groove edges 5a. Furthermore, each transverse groove 5 becomes shallower towards its end on the outside of the tread in a manner known per se (Fig. 3, Fig. 5) and ends at a distance ai determined at the level of the shoulder flank 4a transversely to the circumferential direction (cf. Fig. 5) in front of the side wall (not shown).
[0031] The shoulder section 4 has a width bs measured transversely to the circumferential direction at the level of the shoulder flank 4a (see Fig. 5) and is formed by a half 4' adjacent to the lateral edge of the ground contact area (line L) and a half 4" adjacent to the side wall. The "division" of the shoulder section 4 into the halves 4', 4" therefore refers to the width bs.
[0032] In the half 4" adjacent to the side wall, a number of recesses 6, 7 are formed, distributed over the circumference, extending in groups G, starting from the shoulder flank 4a and, in plan view, elongated rectangular-like recesses 6, 7, wherein the groups G are each located in a separate circumferential section Ui of the shoulder-side profile rib 1, extending between two transverse grooves 5 and reaching from the shoulder-side circumferential groove 2 to the side wall. In each circumferential section Ui, a single group G is provided.
[0033] "Rectangular" means that the corner regions of the recess 6, 7 can be rounded, or that instead of straight boundary edges, curved, for example circular, boundary edges can be provided at the longitudinal ends of the recesses 6, 7. "Rectangular" further means that for each recess 6, 7, a surface can be constructed that encloses it, runs along the shoulder flank 4a, is rectangular in plan view, and occupies at least 95% of the area of the respective recess 6, 7 projected onto the level of the shoulder flank 4a.
[0034] The further design of the depressions 6, 7 is explained below using an individual group G. According to Fig. 2 and Fig. 5, the group G is formed by three depressions 6, 7 which, in plan view, are straight and run completely within the half 4" (Fig. 2) - namely two shorter, edge-side depressions 7 and a longer, central depression 6 running in the area between the edge-side depressions 7. The depression 6 has a center line m1 aligned in its longitudinal extent (Fig. 2) and the depressions 7 each have a center line m2 aligned in their longitudinal extent (Fig. 2).
[0035] As shown in Fig. 2, the recesses 6, 7 arranged in a group G are symmetrical with respect to a center plane E1, which is spanned by the center line rrn of the recess 6 and a straight line perpendicular to the shoulder flank 4a and passing through the center line m1. The center plane E1 is simultaneously a plane of symmetry of the central recess 6. Each recess 7 has a plane of symmetry E2 running parallel to the center plane E1.The depressions 6, 7 run - with respect to the center lines m1, m2 - at an angle a of 90° to the circumferential direction, have - also with respect to the center lines m1, m2 - mutual distances a2 of 0.5 mm to 2.0 mm, determined perpendicular to the center lines m1, m2, and further have a width b1 (depression 6), b2 (depression 7) determined at the level of the shoulder flank 4a in plan view perpendicular to the center line m1, m2, a length ci (depression 6), c2 (depression 7) determined at the level of the shoulder flank 4a along the center line m1, m2 and a depth t1 (Fig. 4, depression 6), t2 determined in the center plane E1 (depression 6) or the symmetry plane E2 (depression 7) as well as perpendicular to the level of the shoulder flank 4a. (Fig. 4, recess 7). The depth ti, t2 (Fig. 4) is 0.3 mm to 1.0 mm, in particular 0.4 mm to 0.6 mm, whereby the depth ti in the exemplary embodiment corresponds to the depth t2. The width b1, b2 (Fig.2) is 0.4 mm to 2.0 mm, wherein in the exemplary embodiment the width b1 is 150% to 250%, in particular 180% to 220%, of the width b2, and wherein the width b2 preferably has a size of 0.6 mm to 1.0 mm. The length c1, C2 is 3.0 mm to 7.5 mm, wherein in the exemplary embodiment the length c1 is at least 2.0 mm greater than the length C2. The recesses 6, 7 have corresponding distances a3 m1 110 mm to 2.0 mm, determined transversely to the circumferential direction, from the end of the half 4" located on the side wall, wherein the recess 6 projects beyond the recesses 7 on the side facing away from the side wall by a projection Ac related to the ends of the center lines rrn, m2, which projection is calculated from the difference between the lengths ci, C2. According to Fig. 4, the recesses 6, 7 are U-shaped in cross-section viewed in plan view oriented perpendicular to the center line QQ, m2.
[0036] According to Fig. 1, successive groups G in the circumferential direction each have a distance a4 from each other, determined in the circumferential direction, based on the center lines m2 (Fig. 2) of the nearest edge-side depressions 7, which is greater than the aforementioned mutual distance a2 (Fig. 2) of the depressions 6, 7 arranged within a group G. The distance a4 is preferably 3.0 mm to 10.0 mm.
[0037] According to Fig. 1, in the half 4" adjacent to the side wall, at every second transverse groove 5, an elongated rectangular-like depression 8 (cf. Fig. 2 and Fig. 5) is formed which adjoins the transverse groove 5 and, in plan view, extends in extension of the transverse groove 5 and runs at an angle of 90° to the circumferential direction. The depression 8 has a depth ts (Fig. 3, Fig. 4) determined perpendicular to the level of the shoulder flank 4a of 0.3 mm to 1.0 mm, in particular of 0.4 mm to 0.6 mm, a width bs (Fig. 2) of 0.4 mm to 2.0 mm, in particular of 0.6 mm to 1.0 mm, to the end of the half 4" lying on the side wall, likewise the distance a3 (Fig. 2) of 1.0 mm to 2.0 mm and to the circumferentially nearest depressions 7 of the corresponding Groups G each have a distance as determined in the circumferential direction. The distance as refers to the center line m2 (Fig.2) of the respective recess 7 and the center line of the recess 8 (not shown in the figures) and is greater than the aforementioned mutual distance a2 (Fig. 2). According to Fig. 5, the recess 8 has a recess edge 8a located on the shoulder flank 4a and adjoining a groove edge 5a tangentially (without kinks). The invention is not limited to the described embodiment.
[0038] The depressions adjoining the transverse grooves are optional. The depressions arranged in groups can in particular comprise up to five depressions. The depressions can run at an angle to the circumferential direction which deviates from 90° by up to 10°, in particular by up to 5°. Furthermore, the depressions can be rectangular when viewed in plan view. The depressions arranged in different groups can run at different angles to one another. The depressions arranged in the same group have mutual distances from one another in the circumferential direction - based on the center lines of the depressions - which are smaller than the distances determined as the smallest distances between the successive groups in the circumferential direction.The distances determined as the smallest distances between the groups following one another in the circumferential direction refer to the center lines of the edge-side depressions of these groups that are closest to one another.
[0039] List of reference symbols
[0040] 1 shoulder-side profile rib
[0041] 2 shoulder-side circumferential grooves
[0042] 3 Interior section
[0043] 3a Outer surface
[0044] 4 shoulder section
[0045] 4a Shoulder flank
[0046] 4', 4" half
[0047] 5 transverse grooves
[0048] 5a Groove edge
[0049] 5b Groove base
[0050] 5c groove flank
[0051] 5d end flank
[0052] 6 Deepening
[0053] 7 Deepening
[0054] 8 Deepening
[0055] 8a Recess edge a1, a2, a3, a4, a5, aQR. Distance b1, b2, b3, bQR, bs width c1, C2 length
[0056] Δc supernatant
[0057] E1 Middle Level
[0058] E2 plane of symmetry
[0059] G Group
[0060] L Line (lateral edge of the ground contact area) m1 m2 Center line
[0061] S5 Arrow (viewing direction) t1 , t2, t3 Depth top maximum depth
[0062] Ui circumferential section
[0063] Z2 Detail a Angle
Claims
Patent claims 1. Vehicle pneumatic tire with a tread and sidewalls, wherein the tread has at least one shoulder-side profile rib (1) with an inner section (3) located within the ground contact area and a shoulder section (4) located outside the ground contact area, the shoulder section (4) having a half (4') adjoining the lateral edge of the ground contact area (line L) and a half (4") adjoining the sidewall, wherein elongated, rectangular or rectangular depressions (6, 7) are formed in the shoulder section (4), which extend at an angle (a) to the circumferential direction which deviates from 90° by up to 10°, characterized in that the depressions (6, 7) are arranged in groups (G), wherein for each group (G) there are at least three circumferentially successive depressions (6, 7) that run parallel to each other and exclusively in the half (4") of the shoulder section (4) adjoining the sidewall.7) with a depth (ti , t2) of 0.3 mm to 1.0 mm and a width (bi , b2) of 0.4 mm to 2.0 mm, wherein the recesses (6, 7) arranged in the same group (G) have circumferential distances (a2) to each other which are smaller than the distances (a4) determined as the smallest distances between the circumferentially successive groups (G).
2. Vehicle pneumatic tire according to claim 1, characterized in that each group (G) includes up to five recesses (6, 7).
3. Vehicle pneumatic tire according to claim 1 or 2, characterized in that groups (G) are provided, each of which includes exactly three recesses (6, 7).
4. Vehicle pneumatic tire according to one of claims 1 to 3, characterized in that the recesses (6, 7) have a length (ci , C2) of 3.0 mm to 7.5 mm.
5. Vehicle pneumatic tire according to claim 4, characterized in that groups (G) are provided in which the length (ci) of the middle recess(s) (6) is at least 2.0 mm greater than the length (C2) of each edge recess (7).
6. Vehicle pneumatic tire according to claim 5, characterized in that the middle recess(s) (6) projects over each edge recess (7) on the side facing away from the side wall with a projection (Ac).
7. Vehicle pneumatic tire according to one of claims 1 to 6, characterized in that the mutual distances (a2) which the recesses (6, 7) arranged in the same group (G) have from each other are 0.5 mm to 2.0 mm.
8. Vehicle pneumatic tire according to one of claims 1 to 7, characterized in that groups (G) are provided in which the width (bi ) of the middle recess(s) (6) is 150% to 250%, in particular 180% to 220%, of the width (b2) of each edge recess (7), wherein the widths (b2) of the edge recesses (7) preferably coincide.
9. Vehicle pneumatic tire according to one of claims 1 to 8, characterized in that the recesses (6, 7) to the end of the half (4") of the shoulder section (4) adjacent to the side wall are determined transversely to the circumferential direction, preferably corresponding distances (as) of have a thickness of 1.0 mm to 2.0 mm.
10. Vehicle pneumatic tire according to one of claims 1 to 9, characterized in that the angle (et) at which the recesses (6, 7) extend to the circumferential direction deviates from 90° by up to 5°.
11. Vehicle pneumatic tire according to one of claims 1 to 10, characterized in that the shoulder-side profile rib (1 ) is provided with transverse grooves (5) is, wherein the groups (G) in which the depressions (6, 7) are arranged are each located in a separate circumferential section (Ui) of the shoulder-side profile rib (1) extending between two transverse grooves (5) to the side wall.
12. Vehicle pneumatic tire according to claim 11, characterized in that in the half (4") of the shoulder section (4) adjacent to the sidewall, at each or every second transverse groove (5), an elongated, rectangular or rectangular further recess (8) adjoining the transverse groove (5), extending at an angle to the circumferential direction deviating from 90° by up to 10°, with a depth (ts) of 0.3 mm to 1.0 mm, in particular of 0.4 mm to 0.6 mm, and a width (bs) of 0.4 mm to 2.0 mm, in particular of 0.6 mm to 1.0 mm, is formed, wherein the further recess (8) preferably extends parallel to the recesses (6, 7) arranged in groups (G) and in particular has a recess edge (8a) adjoining one of the groove edges (5a) of the transverse groove (5).
13. Vehicle pneumatic tire according to one of claims 1 to 12, characterized in that groups (G) are provided in which the recesses (6, 7) are symmetrically formed with respect to a central plane (Ei) perpendicular to the shoulder flank (4a), extending longitudinally along the recesses (6, 7) and centrally through the group (G).
14. Vehicle pneumatic tire according to one of claims 1 to 13, characterized in that the depth (ti , t2) of the depressions (6, 7) is 0.4 mm to 0.6 mm.
15. Vehicle pneumatic tire according to one of claims 1 to 14, characterized in that the distances (a4) which are determined as smallest distances between the circumferentially successive groups (G) are 3.0 mm to 10.0 mm.