Pneumatic vehicle tyre for a motor vehicle

Abstract

The present invention relates to a pneumatic vehicle tyre (1) having a tyre carcass (2), a sidewall (4, 6) and a tread (8) for a motor vehicle, wherein the tread (8) is spaced apart from the tyre carcass (2) by a connecting plane (18). The side wall has depressions (12) below the connecting plane (18), in the direction of a centre of the pneumatic vehicle tyre (1), for cooling the pneumatic vehicle tyre (1). The pneumatic vehicle tyre (1) is, for example, a retreaded tyre for a utility vehicle.

Description

[0001] Description

[0002] Vehicle pneumatic tires for a motor vehicle

[0003] The present invention relates to a vehicle pneumatic tire comprising a tire carcass, a sidewall and a tread for a motor vehicle, in particular a retreaded vehicle pneumatic tire for a truck.

[0004] Retreaded tires are less expensive to manufacture than new tires and are frequently used, especially in the commercial vehicle sector. To manufacture a retreaded tire, the tread of a used tire is roughened or peeled off, and then a new tread with a tire profile is applied and vulcanized.

[0005] US Patent 2024 / 051345 A1 discloses a tread with a running surface for a heavy construction vehicle, wherein the tread exhibits an improved compromise between resistance to mechanical attack from stony ground and traction on muddy ground. Ventilation cavities are arranged in a side face of the tread, which do not open into the running surface when the tread is new.

[0006] CN 101439647 A discloses a pneumatic tire for a passenger car, comprising a tread and a sidewall with a circumferential groove containing holes for improved heat dissipation. Rectangular recesses open into this groove and are directed towards the center of the tire. Further rectangular recesses for improved heat dissipation are arranged in a side surface of the tread. Figures 1a and 1b show pneumatic tires for trucks, each featuring recesses V in a side surface of the tread.

[0007] It is an object of the present invention to provide a vehicle pneumatic tire comprising a tire carcass, a sidewall and a tread, which has improved mileage performance.

[0008] This problem is solved by a vehicle pneumatic tire with the features of claim 1.

[0009] Preferred embodiments of the invention are the subject of the dependent claims.

[0010] According to a first aspect of the invention, a pneumatic tire for a motor vehicle comprises a tire carcass, a sidewall, and a tread, the tread being separated from the tire carcass by a connecting plane. The sidewall has recesses below the connecting plane, i.e., on a smaller tire radius, directed towards the center of the tire, for cooling purposes. The pneumatic tire can be either a tubeless tire or a tire with an inner tube.

[0011] The indentations are arranged periodically in the sidewalls and represent windows that are not connected to each other, creating improved heat transfer in and out of the vehicle's pneumatic tire.

[0012] According to a further aspect of the invention, the recesses are trapezoidal in shape. The trapezoidal shape is characterized by good resistance to mechanical deformation under tire load. In particular, the recesses can have the shape of an isosceles trapezoid.

[0013] According to another aspect of the invention, the recesses have a maximum depth of 5 mm.

[0014] According to another aspect of the invention, the recesses are arranged in an area of ​​the vehicle pneumatic tire on the sidewall which has the smallest possible distance to the belt edges of the vehicle pneumatic tire.

[0015] According to another aspect of the invention, the recesses have the same shape and size and are equidistant from each other.

[0016] According to another aspect of the invention, the recesses are arranged in a shoulder strip of the side wall.

[0017] According to another aspect of the invention, the vehicle pneumatic tire is a retreaded vehicle pneumatic tire. Since the indentations are located below the bonding plane, they remain in the shoulder after buffing the tread for retreading and can continue to function as cooling elements.

[0018] According to another aspect of the invention, the vehicle pneumatic tire is a commercial vehicle tire.

[0019] Further features of the present invention will become apparent from the following description and the attached claims in conjunction with the information.

[0020] Figure overview Fig. 1 a, 1 b show vehicle tires for trucks according to the prior art, which have indentations in a side surface of the tread;

[0021] Fig. 2 shows an area of ​​a vehicle pneumatic tire of a motor vehicle according to the invention;

[0022] Fig. 3 shows the result of a temperature simulation for an area of ​​the vehicle tire of Fig. 2;

[0023] Fig. 4 shows the result of a temperature simulation for a section of a vehicle tire of a motor vehicle according to the prior art; and

[0024] Fig. 5 shows an example of the design of a recess as an isosceles trapezoid.

[0025] Character description

[0026] To better understand the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. The same reference numerals are used in the figures for identical or equivalently acting elements and are not necessarily described again for each figure. It is understood that the invention is not limited to the embodiments shown and that the described features can also be combined or modified without departing from the scope of protection of the invention as defined in the appended claims.

[0027] Fig. 2 schematically shows a side view of an area of ​​a

[0028] Figure 1 shows a pneumatic tire 1 of a motor vehicle. The pneumatic tire 1 has a tire carcass 2 and sidewalls 4 and 6, as well as a tread 8 with profile grooves 10. The pneumatic tire 1 is, for example, a retreaded tire for a truck.

[0029] The sidewall 4 has a plurality of recesses 12, which are evenly distributed over the entire sidewall 4. In this embodiment, the recesses 12 have a trapezoidal shape, with a longer side 14 of the recesses 12 directed inwards, towards the center of the vehicle tire 1, and a shorter side 16 of the recesses 12 directed outwards. The vehicle tire 1 is preferably a belted tire with a belt that typically comprises several layers of fabric made of nylon and / or steel mesh, not visible in Fig. 2. The belt is arranged on the tire carcass 2 and improves the running characteristics of the vehicle tire 1.

[0030] The recesses 12 provide improved cooling of the belt in heavy-duty operation, and in particular improved cooling for edges of the belt arranged in the tire carcass 2, where increased temperature stress occurs in heavy-duty operation.

[0031] In this embodiment, the recesses 12 all have the same shape and size and are equidistant from each other.

[0032] Vehicle tires, especially those used for heavy-duty applications, can heat up considerably when driving on a road due to the movement of the belts within the tire 1, which generates heat. High temperatures can weaken the rubber, particularly around the belt edges of the belts arranged on the tire carcass 2. This acts as a driving force for belt edge failure and can lead to damage to the vehicle tire 1. The recesses 12 are arranged periodically on the sidewalls 4 and 6 and represent windows that are not interconnected, in order to improve heat transfer within the vehicle tire 1. Instead of a trapezoidal shape, the recesses can alternatively have other geometric shapes, with the recesses 12 preferably having a maximum depth of 5 mm.In a preferred embodiment, the recesses 12 are arranged directly below a base rubber line 18, which forms a connecting plane 18 between the tread 8 and the tire carcass, at the smallest possible distance to the belt edges of the belt arranged on the tire carcass 2, as this ensures an optimal cooling effect. The base rubber line 18 separates the tire carcass 2 from the tread 8. Preferably, the recesses 12 are located in a region extending from the base rubber line 18 to approximately 30 mm below it.

[0033] Figure 3 schematically shows a cross-sectional result of a temperature simulation for a region of the vehicle tire 1. The vehicle tire 1 has a belt with several fabric layers 20 arranged over the tire carcass 2, the fabric layers 20 having belt edges 22 facing the sidewall 6. The result is based on a temperature simulation simulating heavy-duty operation of the vehicle tire 1, during which it heats up considerably. In this temperature simulation, the tire carcass 2, the sidewall 6, and the tread 8 exhibit temperature ranges with widely varying temperatures from cold to hot. The highest temperatures are found in the areas around the belt edges 22 of the fabric layers 20 within a region 24 of the vehicle tire 1, indicated by ellipses and located below the base rubber line 18, essentially between the belt edges 22 and the sidewall 6.The recesses 12 are therefore arranged in a region 26 of the vehicle tire 1 on the sidewall 6, which has the smallest possible distance to the belt edges 22. Figure 4 schematically shows a cross-sectional view of the result of a temperature simulation for a region of a prior art vehicle tire 50. The vehicle tire 50 has a sidewall 52 without recesses. The operating conditions correspond to those for the vehicle tire according to Figure 3. As can be seen in Figure 4, the region 24 of the vehicle tire 1 with the highest temperatures, indicated by ellipses, is significantly larger than is the case for the vehicle tire 1 in Figure 3.

[0034] Fig. 5 shows an example of a recess 12 configured as an isosceles trapezoid. The trapezoid has a short side A with a length in the range of 2 mm to 30 mm, preferably 13 mm. The trapezoid also has a long side B parallel to the short side A with a length in the range of 1 x A to 2.5 x A, preferably 1.7 x A. The two other sides C have identical lengths. These are chosen such that the height H of the trapezoid has a length in the range of 0.5 x A to 2 x A, preferably 1 x A. Of course, the recess 12 can also be configured as a non-isosceles trapezoid or in another shape. The angle α defined by the two other sides C is preferably in the range of 15° to 60°, preferably 45°.

[0035] Reference symbol list

[0036] 1 vehicle pneumatic tire

[0037] 2 tire carcass

[0038] 4, 6 side walls

[0039] 8 treads

[0040] 10 profile grooves

[0041] 12 depressions

[0042] 14, 16 pages of the in-depth study 12

[0043] 18 Connection level

[0044] 20 layers of tissue

[0045] 22 belt edges

[0046] 24, 26 areas of the vehicle pneumatic tire 1

[0047] 50 vehicle pneumatic tires

[0048] 52 side wall

[0049] A Short side

[0050] B Long side

[0051] C Next page

[0052] H height

[0053] V depressions

Claims

Patent claims 1. Vehicle pneumatic tire (1 ) comprising a tire carcass (2), a sidewall (4, 6) and a tread (8) for a motor vehicle, wherein the tread (8) is spaced apart from the tire carcass (2) by a connecting plane (18), wherein the sidewall has recesses (12) below the connecting plane (18), in the direction of a center of the vehicle pneumatic tire (1 ), for cooling the vehicle pneumatic tire (1 ).

2. Vehicle pneumatic tire (1 ) according to claim 1 , wherein the recesses (12) are trapezoidal in shape.

3. Vehicle pneumatic tire (1 ) according to claim 1 or 2, wherein the recesses (12) have a maximum depth of 5 mm.

4. Vehicle pneumatic tire (1 ) according to claim 1 , 2 or 3, wherein the recesses (12) are arranged in a region (26) of the vehicle pneumatic tire (1 ) on the sidewall (4, 6) which has the smallest possible distance to belt edges (22) of the vehicle pneumatic tire (1 ).

5. Vehicle pneumatic tire (1) according to one of the preceding claims, wherein the recesses (12) have the same shape and size and / or are spaced equally apart from each other.

6. Vehicle pneumatic tire (1) according to one of the preceding claims, wherein the recesses (12) are arranged in a shoulder strip of the sidewall (4, 6).

7. Vehicle pneumatic tire (1 ) according to one of the preceding claims, wherein the vehicle pneumatic tire (1 ) is a retreaded vehicle pneumatic tire.

8. Vehicle pneumatic tire (1 ) according to one of the preceding claims, wherein the vehicle pneumatic tire (1 ) is a commercial vehicle tire.

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