Pneumatic vehicle tire

Abstract

The invention relates to a pneumatic vehicle tyre having a profiled tread, the tread having at least one circumferential groove (1) which extends in a planar view, in particular straightly in a circumferential direction, and which has a groove base (3) and two groove flanks (4), wherein projections (5) are formed on the groove base (3), arranged in a distributed manner over the circumference of the tread and functioning as a muffler, each projection (5) having a first plane of symmetry (E1) extending in plan view in the direction of extension of the circumferential groove (1) and a second plane of symmetry (E2) extending in plan view perpendicular to the first plane of symmetry (E1), and wherein each projection (5) consists of a central projection portion (6) formed centrally in the circumferential groove (1) and two lateral projection portions (7) facing the groove flanks (4). The central projection (6) has the shape of an oval extending in an elongated manner in the direction of extension of the first plane of symmetry (E1), in particular in the shape of an ellipsoid extending in an elongated manner in the direction of extension of the first plane of symmetry (E1), as viewed in a plan view. According to the invention, the central projection (6) is designed in the form of an oval, in particular an ellipsoid, which is centrally flat in the radial direction, and the side projections (7) each have a smaller volume than the central projection (6), are designed in the form of a nose, and have a nose bridge which descends from the central projection (6).

Description

Technical Field

[0001] The present invention relates to a vehicle pneumatic tire having a tread with a tread pattern, the tread having at least one circumferential groove extending in a plan view, in particular straightly in a circumferential direction, the circumferential groove having a groove base and two groove side surfaces, wherein protrusions are formed on the groove base and are arranged in a distributed manner on the circumference of the tread and function as mufflers, wherein each protrusion has a first symmetry plane extending in the extension direction of the circumferential groove in a plan view, and a second symmetry plane extending perpendicular to the first symmetry plane in a plan view, and wherein each protrusion consists of a central protrusion portion formed centrally in the circumferential groove and two side protrusion portions facing the groove side surfaces. Background Art

[0002] It is well known that circumferential grooves formed on the tread of a pneumatic tire of a vehicle and extending straight in the circumferential direction are particularly advantageous for drainage and thus for the hydroplaning performance of the tire. In order to suppress the propagation of sound waves whose frequencies are within the audible range of humans and are mainly formed in the straight circumferential grooves during driving, protrusions that function as mufflers ("noise breakers") are usually formed in the circumferential grooves, however, these protrusions affect the drainage capability.

[0003] A tire of the type mentioned in the opening paragraph is known, for example, from WO 2010 / 102 683 A1. The tread of the tire has a circumferential groove with a projection formed on the groove base, wherein, according to an embodiment, the projection is respectively composed of a central projection part located centrally in the circumferential groove and two side projection parts facing the sides of the groove. The projection parts respectively have the contour of the outer surface of a cylinder, the outer surface of the side projection parts being based on a larger radius than the outer surface of the central projection part. A pneumatic vehicle tire having a tread with projections implemented in this way should have reduced tire-road noise and good hydroplaning properties. Summary of the invention

[0004] The invention is based on the object of further improving the drainage capacity of the circumferential grooves in the region of the projections, while maintaining the effect of suppressing the propagation of sound waves of the projections, in a pneumatic vehicle tire of the type mentioned in the introduction.

[0005] According to the present invention, the proposed object is achieved by the following means:

[0006] When viewed in a plan view, the central raised portion has a shape of an oval body extending in an elongated shape along the extension direction of the first symmetry plane, in particular, a shape of an ellipsoid extending in an elongated shape along the extension direction of the first symmetry plane, and

[0007] The central raised part is designed as an oval body, in particular a subsegment of an ellipsoid, which is flattened in the center in the radial direction.

[0008] The side raised portions each have a smaller volume than the central raised portion, are designed in a nose shape, and have a nose bridge portion that descends from the central raised portion.

[0009] When driving on wet roads, the central raised part is flowed around and past by water in a particularly low-swirl manner due to its shape and is also used to divert the water flow in a particularly low-swirl manner. Due to the central flattening of the central raised part, a larger groove cross section is obtained in the raised area, which is beneficial for drainage. The raised part (due to its unique raised part) has an excellent effect on suppressing the propagation of sound waves in the circumferential groove.

[0010] According to a preferred embodiment, the central raised portion is flattened in the radial direction due to a circular platform extending parallel to the tread periphery. This flat design of the central raised portion is particularly advantageous for drainage capabilities.

[0011] Another preferred embodiment is that the central raised portion is delimited in each extension direction of the circumferential groove by end faces extending toward the groove bottom, the end faces forming subsections of the surface of an oval or ellipsoid. These end faces are further advantageous for the mentioned low-swirl water to flow around and through the central raised portion.

[0012] In the last preferred embodiment, it is advantageous that each end face extends at an angle of 30° to 50°, in particular 35° to 45°, to the radial direction with respect to a straight auxiliary line connecting the ends of the end faces, when viewed in a cross section extending in the first symmetry plane. In addition, this helps water to flow over the protrusions in a low-swirl manner.

[0013] According to another preferred embodiment, the protrusion has a maximum width projected onto the tread periphery in the second symmetry plane, which is 50% to 85%, in particular 65% to 75%, of the width of the circumferential groove transverse to the extension direction of the circumferential groove in a plan view and determined at the tread periphery. This helps to further improve the drainage capacity of the circumferential groove in the protrusion area.

[0014] The preferred embodiments mentioned below relate to the size of the protrusions. These embodiments can be combined with each other in any manner and are advantageous in terms of suppressing the conflict between the acoustic wave propagation effect of the protrusions and the drainage capability of the circumferential grooves.

[0015] The first embodiment is characterized in that, viewed in plan view, the central raised portion has, in the first plane of symmetry, a maximum length determined at the level of the tread depth of 10.0 mm to 15.0 mm.

[0016] A second embodiment consists in that the central raised portion has a maximum height determined in radial direction relative to the level of the tread depth which is 25% to 55%, in particular 30% to 50%, preferably 35% to 45% of the tread depth.

[0017] According to a third embodiment, observed in a plan view, the central raised portion has a width in the second symmetry plane determined at the level of the platform surface, which width is 30% to 55%, in particular 35% to 50%, of the width of the circumferential groove determined at the periphery of the tread transversely to the extension direction of the circumferential groove in a plan view.

[0018] It is also advantageous that the lateral projections are spaced apart from the groove sides, in particular spaced equally apart from the nearest groove sides in a plan view in a manner determined perpendicularly to the first symmetry plane. This is particularly advantageous for drainage capabilities in the projection region, since water is guided through in the same manner on both sides of the projection.

[0019] According to another preferred embodiment, each lateral projection is delimited by a single, outwardly curved surface. This helps the lateral projection to be flowed around and through by water in a particularly low-swirl manner.

[0020] In the above preferred embodiment, it is advantageous that the outwardly curved surface extends at an angle of 30° to 50°, in particular 35° to 45°, to the radial direction relative to a straight auxiliary line connecting the ends of the outwardly curved surface, viewed in a section lying in the second symmetry plane.

[0021] According to the following two further preferred embodiments that can be combined, the side raised portions have a size specifically matched with the central raised portion. This helps maintain the effect of suppressing the propagation of sound waves and is also beneficial to the drainage capacity of the circumferential grooves.

[0022] One of these embodiments is characterized in that, observed in a plan view, each side raised portion has a maximum length determined along the extension direction of the circumferential groove at the level of the groove bottom, and the maximum length of the side raised portion is 20% to 35%, in particular 26% to 32% of the maximum length of the central raised portion.

[0023] A second of these embodiments is characterized in that each side raised portion has a maximum height determined in a radial direction relative to the level of the tread depth, and the maximum height of the side raised portion is 60% to 100%, in particular 70% to 90%, preferably 75% to 85% of the maximum height of the central raised portion.

[0024] It is also particularly advantageous for drainage capabilities if each side raised portion has a volume that is 10% to 25% of the volume of the central raised portion.

[0025] Another preferred embodiment is characterized in that three to twenty, preferably at least fifteen, projections are formed in the circumferential groove, and the projections are especially arranged such that successively arranged projections have a determined mutual spacing in the circumferential direction that is equal or differs from each other by at most 20.0 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further features, advantages and details of the present invention will now be described in detail with the aid of the accompanying drawings which schematically illustrate embodiments of the present invention. In the drawings:

[0027] Figure 1 An oblique view showing a detail of the tread of a pneumatic vehicle tire according to an embodiment of the invention in the region of the circumferential grooves,

[0028] Figure 2 Show Figure 1 A plan view of a partial part of

[0029] Figure 3 Shown along Figure 2 The section along line III-III, and

[0030] Figure 4 Shown along Figure 2 The cross section along line IV-IV.

[0031] List of Reference Numerals

[0032] 1.................Circumferential groove

[0033] 1a................Frequency edge

[0034] 2.................Convex tread

[0035] 3.................Grooved bottom

[0036] 4.................Groove side

[0037] 5.................Bump

[0038] 6.................Central raised part

[0039] 6a................Platform surface

[0040] 6a'...............Edge

[0041] 6b................End face

[0042] 7.................Side raised part

[0043] 7a................Noodles

[0044] 8.................Transition rounded part

[0045] b1, B UR ............width

[0046] b V ................Maximum width

[0047] c1, c2.............maximum length

[0048] E1, E2.............Symmetrical plane

[0049] h1, h2.............Height

[0050] H1, H2.............Auxiliary lines

[0051] T UR ................Tread depth

[0052] α, β, γ........angle DETAILED DESCRIPTION

[0053] The vehicle pneumatic tire according to the present invention is a tire for motor vehicles, especially for multi-track motor vehicles, and preferably a radial tire for passenger motor vehicles, vans or light trucks (light trucks (LKW) with a permissible total weight ≤ 7.5t).

[0054] Figure 1 An oblique view showing a detail of the tread of a pneumatic vehicle tire in the region of a circumferential groove 1 which, in plan view, extends straight and circumferentially around, separating ridges 2 (e.g. tread strips) from one another. The regions of the tread which are not shown may be embodied in a known manner.

[0055] The circumferential groove 1 is a tread depth T in the radial direction set for the corresponding tire type. UR ( Figure 3 , Figure 4 ) is implemented, the tread depth for passenger motor vehicles (PKW), vans and light trucks is usually 6.5 mm to 13.0 mm, and the circumferential groove has a width B of 6.0 mm to 10.0 mm in the axial direction at the periphery of the tread. UR ( Figure 2 , Figure 3 ), the circumferential groove also has a U-shaped cross section ( Figure 3 ) and two groove edges 1a located at the periphery of the tread and extending straight in the circumferential direction in a plan view. The circumferential groove 1 is defined by a groove bottom 3 and two groove side faces 4. Figure 3 , viewed in a cross section oriented in the axial direction in a plan view (see Figure 2 The groove bottom 3 extends in an arc shape. When viewed in the cross section mentioned, the groove flanks 4 extend straight and each at an angle α of 0° to 15°, in particular 3° to 10°, to the radial direction.

[0056] like Figure 1 and Figure 2 As shown in the figure, a local protrusion 5 is formed in the shown section of the circumferential groove 1, which is located on the groove bottom 3, is equally spaced from the groove side 4 in the axial direction, and is not substantially larger than the groove side 4 in the plan view ( Figure 2 ) in the circumferential direction. The protrusions 5 act as "mufflers" and reduce the noise radiation of the tire during driving (especially in the frequency range of 1000 Hz). A plurality of protrusions 5 are provided in the circumferential groove 1, wherein in particular three to twenty, preferably at least fifteen, protrusions 5 are provided. The protrusions 5 are arranged such that the protrusions 5 arranged in succession have a mutual spacing in the circumferential direction that is determined, equal or differs from each other by a maximum of 20.0 mm. That is, the difference between the maximum spacing and the minimum spacing is at most 20.0 mm.

[0057] The projection 5 has a symmetry plane E1 extending in the circumferential direction in a plan view ( Figure 2 ), and a symmetry plane E2 extending in the axial direction in a plan view ( Figure 2 ), and the protrusion is composed of a central protrusion 6 and two nose-shaped side protrusions 7 facing different groove sides 4. Therefore, the symmetry plane E1 is extended by the circumferential direction and the radial direction, and the symmetry plane E2 is extended by the axial direction and the radial direction. The protrusion 5 has a maximum width b determined in the axial direction projected onto the tread periphery in the symmetry plane E2. V (width at widest position, Figure 2 ), the maximum width is the width B of the circumferential groove 1 UR ( Figure 2 ) of 50% to 85%, especially 65% ​​to 75%.

[0058] The central raised portion 6 is about the symmetry planes E1 and E2 ( Figure 2 ) symmetrically, when viewed in a plan view and ignoring the side raised portions 7, the central raised portion has the shape of an ellipsoid extending elongated in the circumferential direction ( Figure 2), and the overall shape is a sub-segment of an ellipse that is flattened in the radial direction. The central raised portion 6 is formed in the radial direction by a platform surface 6a (see FIG. 6 ) extending parallel to the tread periphery and having a circular shape in a plan view. Figure 3 , Figure 4 ) and in each circumferential direction are respectively defined by an end face 6b extending between the groove bottom 3 and the platform face 6a (see Figure 4 ) is defined as a sub-segment of the surface of the ellipsoid.

[0059] The platform surface 6a is defined by a sharp edge 6a' which is circumferentially circular and makes the central raised portion 6 flat in the center.

[0060] according to Figure 4 , in the cross section located on the symmetry plane E1 (see Figure 2 Each end face 6b extends at an angle β of 30° to 50°, in particular 35° to 45°, to the radial direction with respect to a straight auxiliary line H1 connecting the ends of the end faces 6b (as viewed from the center line IV-IV).

[0061] according to Figures 2 to 4 , the central raised portion 6 is on the symmetry plane E1 ( Figure 2 ) has a tread depth T in the circumferential direction UR ( Figure 4 ) is determined at the level of 10.0 mm to 15.0 mm (the length at the longest position, Figure 2 , Figure 4 ); the central raised part is on the symmetry plane E2 ( Figure 2 ) has a width b1 ( Figure 2 , Figure 3 ), which is the width B of the circumferential groove 1 UR ( Figure 2 , Figure 3 ) 30% to 55%, especially 35% to 50%; and the central raised portion has a radial direction relative to the tread depth T UR ( Figure 3 , Figure 4 ) is determined based on the maximum height h1 (the height at the highest position) of the platform surface 6a. Figure 3 , Figure 4 ), the maximum height is the tread depth T UR ( Figure 3 , Figure 4 ), 25% to 55%, especially 30% to 50%, preferably 35% to 45%.

[0062] Also like Figure 2As shown, the side protrusions 7 are implemented to be symmetrical about the symmetry plane E2 , wherein one side protrusion 7 is positioned symmetrically with respect to the other side protrusion 7 about the symmetry plane E1 , and wherein each side protrusion 7 has a smaller volume than the central protrusion 6 .

[0063] Each lateral projection 7 also has a single, rounded, and therefore edgeless, outwardly curved surface 7a (see Figure 1 ) which descends in the plane of symmetry E2 from the central raised portion 6 towards the groove bottom 3 and ends at the groove bottom ( Figure 3 ). Therefore, each side raised portion 7 has a nose bridge portion that descends from the central raised portion 6 toward the groove bottom 3. Therefore, the nose bridge portion is the portion of the surface 7a that is located on the symmetry plane E2 ( Figure 3 ).according to Figure 3 , observed in the cross section located in the symmetry plane E2 (see Figure 2 The surface 7a is continuously bent outward in an arc shape, so that the straight auxiliary line H2 connecting the end of the surface 7a is located inside the side protrusion 7, and the surface 7a extends at an angle γ of 30° to 50°, especially 35° to 45° to the radial direction with respect to the auxiliary line H2.

[0064] The side raised portions 7 have a maximum length c2 (the length at the longest position, Figure 2 ), which is the maximum length c1 of the central raised portion 6 ( Figure 2 ) 20% to 35%, in particular 26% to 32%; and in the radial direction relative to the tread depth T UR The maximum height h2 (the height at the highest position, Figure 3 ), which is the maximum height h1 of the central raised portion 6 ( Figure 3 ), 60% to 100%, in particular 70% to 90%, particularly preferably 75% to 85%. Preferably, the volume of each side convex portion 7 is 10% to 25% of the volume of the central convex portion 6.

[0065] In the illustrated embodiment, transition rounded portions 8 ( Figures 1 to 3 ), the two ends of the transition chamfer are located on the groove bottom 3 ( Figure 1 When determining the corresponding, mentioned dimensions (height h2 and length c2 of the lateral projection 7), the transition radius 8 ( Figure 2 , Figure 3 ).

[0066] The invention is not restricted to the described exemplary embodiments.

[0067] The projections may be connected to one or both groove sides, respectively. The projections may also have the shape of any sub-segment of a centrally flattened oval, respectively. The platform surface may have a shape different from the shape described. The tread has at least one circumferential groove in which the projection is located. In a preferred manner, the projection is formed in each circumferential groove of the tread. The projections located in the circumferential grooves extending in an axially adjacent manner to each other are preferably positioned so that the projections in one circumferential groove are staggered in the circumferential direction relative to the projections in the corresponding adjacent other circumferential groove.

[0068] The circumferential grooves comprising the protrusions may also extend in a zigzag or wavy shape when viewed in a plan view, wherein the circumferential grooves preferably have a "lookthrough effect", ie, the circumferential grooves may be seen through when viewed in a cross section oriented in the axial direction in a plan view.

[0069] The circumferential grooves extending in a zigzag shape are composed of circumferential groove sections that are arranged in succession along the circumferential direction and extend straightly in the plan view. The protrusions in the circumferential grooves extending in a zigzag shape have a first symmetry plane, which, when observed in the plan view, extends along the extension direction of the circumferential grooves, i.e., along the extension direction of the respective circumferential groove sections. Such protrusions also have a second symmetry plane, which, when observed in the plan view, extends perpendicular to the first symmetry plane. Therefore, the first symmetry plane is expanded by the extension direction and radial direction of the respective circumferential groove sections. Therefore, the second symmetry plane is expanded by the straight line and radial direction extending perpendicular to the first symmetry plane in the plan view. The width of the circumferential grooves extending in a zigzag shape is determined in the plan view in a manner transverse to the extension direction of the circumferential grooves and at the tread periphery.

[0070] The protrusion formed in the circumferential groove extending in a wave shape is implemented to be consistent with the protrusion located in the circumferential groove extending straight in a plan view. Therefore, the extending direction of the circumferential groove extending in a wave shape is the accurate circumferential direction.

Claims

1. A pneumatic vehicle tire having a tread with a tread, the tread having at least one circumferential groove (1) extending in a plan view, in particular straightly in a circumferential direction, the circumferential groove having a groove base (3) and two groove side faces (4), wherein protrusions (5) functioning as mufflers and arranged in a distributed manner over the circumference of the tread are formed on the groove base (3), wherein each protrusion (5) has a first symmetry plane (E1) extending in a plan view along the extension direction of the circumferential groove (1) and a second symmetry plane (E2) extending perpendicular to the first symmetry plane (E1) in a plan view, and wherein each protrusion (5) consists of a central protrusion portion (6) formed centrally in the circumferential groove (1) and two side protrusion portions (7) facing the groove side faces (4), It is characterized in that When viewed in a plan view, the central raised portion (6) has the shape of an oval body extending in an elongated shape along the extension direction of the first symmetry plane (E1), in particular, the shape of an ellipsoid extending in an elongated shape along the extension direction of the first symmetry plane (E1), and The central raised portion is designed as an oval body, in particular a subsegment of an ellipsoid, which is flattened in the center in the radial direction. The side raised portions (7) have a smaller volume than the central raised portion (6), are designed in a nose shape, and have a nose bridge portion that descends from the central raised portion (6).

2. The vehicle pneumatic tire according to claim 1, characterized in that: The central raised portion (6) is flattened in the radial direction due to a circular platform surface (6a) extending parallel to the tread periphery.

3. The vehicle pneumatic tire according to claim 1 or 2, characterized in that: The central raised portion (6) is delimited in each direction of extension of the circumferential groove (1) by an end face (6b) extending towards the groove base (3), the end face constituting a sub-segment of the surface of the oval or ellipsoid.

4. The vehicle pneumatic tire according to claim 3, characterized in that: When viewed in a cross section extending in the first symmetry plane (E1), each end face (6b) extends at an angle (β) of 30° to 50°, in particular 35° to 45°, to the radial direction with respect to a straight auxiliary line (H1) connecting the ends of the end faces (6b).

5. The vehicle pneumatic tire according to any one of claims 1 to 4, characterized in that: The protrusion (5) has a maximum width (b) projected onto the tread periphery in the second symmetry plane (E2). V ), the maximum width is the width (B) of the circumferential groove (1) transverse to the extension direction of the circumferential groove (1) in a plan view and determined at the periphery of the tread UR ) of 50% to 85%, especially 65% ​​to 75%.

6. The vehicle pneumatic tire according to any one of claims 1 to 5, characterized in that: When viewed in plan, the central raised portion (6) has a tread depth (T UR ) at the level of the substrate and having a maximum length (c1) of 10.0 mm to 15.0 mm.

7. The vehicle pneumatic tire according to any one of claims 1 to 6, characterized in that: The central raised portion (6) is relatively close to the tread depth (T UR ) has a maximum height (h1) determined in the radial direction, the maximum height being the tread depth (T UR ), 25% to 55%, especially 30% to 50%, preferably 35% to 45%.

8. The vehicle pneumatic tire according to any one of claims 2 to 7, characterized in that: The central raised portion (6) has, in the second symmetry plane (E2), a width (b1) determined at the level of the platform surface (6a), when viewed in plan, which is the width (B1) of the circumferential groove (1) transverse to the extension direction of the circumferential groove (1) in plan view and determined at the periphery of the tread. UR ), 30% to 55%, especially 35% to 50%.

9. The vehicle pneumatic tire according to any one of claims 1 to 8, characterized in that: The lateral raised portions (7) are spaced apart from the groove side surfaces (4), in particular are equally spaced apart from the nearest groove side surfaces (4) in a manner determined perpendicularly to the first symmetry plane (E1) in a plan view.

10. The vehicle pneumatic tire according to any one of claims 1 to 9, characterized in that: Each lateral raised portion (7) is delimited by a single, outwardly curved surface (7a).

11. The vehicle pneumatic tire according to claim 10, characterized in that: When viewed in a cross section located in the second symmetry plane (E2), the outwardly curved surface (7a) extends at an angle (γ) of 30° to 50°, in particular 35° to 45°, to the radial direction with respect to a straight auxiliary line (H2) connecting the ends of the outwardly curved surface (7a).

12. The vehicle pneumatic tire according to any one of claims 6 to 11, characterized in that: When viewed in plan, each side raised portion (7) has a maximum length (c2) determined along the extension direction of the circumferential groove (1) at the level of the groove bottom (3), and the maximum length of the side raised portion is 20% to 35%, in particular 26% to 32% of the maximum length (c1) of the central raised portion (6).

13. The vehicle pneumatic tire according to any one of claims 7 to 12, characterized in that Each side protrusion (7) has a relative width to the tread depth (T UR ) have a maximum height (h2) determined in the radial direction, the maximum height of the side protrusions being 60% to 100%, in particular 70% to 90%, preferably 75% to 85% of the maximum height (h1) of the central protrusion (6).

14. The vehicle pneumatic tire according to any one of claims 1 to 13, characterized in that: Each side raised portion (7) has a volume that is 10% to 25% of the volume of the central raised portion (6).

15. The vehicle pneumatic tire according to any one of claims 1 to 14, characterized in that Three to twenty, preferably at least fifteen, projections (5) are formed in the circumferential groove (1), and the projections (5) are particularly arranged so that the projections (5) arranged successively have a mutual spacing in the circumferential direction that is determined, equal or differs from each other by at most 20.0 mm.

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