Configuration of vehicle tires

Abstract

The present subject matter relates to a tire tread configuration for pneumatic vehicle tires. The tread portion of the tire comprises a central region having a first axial width (TW1) and a pair of adjoining regions on either side of the central region, wherein the central region has a first radius of curvature (R1) and the pair of adjoining regions have a second radius of curvature (R2). Each of the sidewall portions of the tire includes an additional rubber layer.

Description

CONFIGURATION OF VEHICLE TIRESTECHNICAL FIELD

[0001] The present subject matter relates, in general, to vehicle tires and, particularly but not exclusively, to tires to be used in agricultural vehicles.BACKGROUND

[0002] Tires support load of a vehicle and provide for impact handling, drivability, and safety of the vehicle.

[0003] A tire is mounted on a wheel’s rim to transfer the load of the vehicle from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Most tires, such as those for automobiles, are pneumatically inflated structures filled with air, which provide a flexible cushion that absorbs shock when the tire rolls over uneven surfaces. Tires provide a footprint, called a contact patch, that is designed to withstand the weight of the vehicle by providing a bearing pressure that will not deform the surface excessively.

[0004] The tire has a crown or center region, sidewall region on either side of the center region, and beads on either side of the sidewall region. The center region, also known as the tread of the tire, may be understood as a region of the tire formed along a complete circumference of the tire and spanning along a width of the tire, which contacts with a surface during rotation. The beads may be understood as the edges of the tire. The beads contact with a wheel during the mounting of the tire. The sidewall region is a portion of the tire between the center region and the beads of the tire.

[0005] Vulcanized and treated rubber is used to make the tread of the tire. The tread is often carved in diverse configuration by way of tread blocks, tread grooves, lugs, tread voids, tie-bar, and the like. The configuration of the tread affects contact and interaction of the tire with road and thus affects traction ofthe vehicle. Hence, the tread configuration has a crucial role in tire life, vehicle handling, safety, and ease of driving.BRIEF DESC IPTION OF DRAWINGS

[0006] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

[0007] Fig. 1 a illustrates perspective view of a pneumatic tire, in accordance with an embodiment of the present subject matter.

[0008] Fig. 1 b illustrates front view of a tread portion of the pneumatic tire with tire, in accordance with another embodiment of the present subject matter.

[0009] Fig. 2 illustrates a cross section of the pneumatic tire, in accordance with an implementation of the present subject matter.

[0010] Fig. 3 illustrates a cross sectional view of the pneumatic tire, in accordance with yet another embodiment of the present subject matter.

[0011] Fig. 4 illustrates a side cross sectional view of the pneumatic tire, in accordance with yet another implementation of the present subject matter.

[0012] Fig. 5 illustrates a contact area of the pneumatic tire with respect to the ground under different loads and pressure using Finite Element Analysis (FEA) and physical testing, in accordance with yet another implementation of the present subject matter.DETAILED DESCRIPTION

[0013] The present subject matter relates to aspects relating to tire tread and configuration for the tire tread.

[0014] Sprayers are specialized agricultural vehicles for applying liquids, such as fertilizers or insecticides, to crops planted in fields and plantations.The sprayers, for example, row-crop field sprayers may be self-propelled. In fields and plantations, the crops may be planted and grown in multiple parallel rows. Adjacent pairs of rows are tightly spaced for maximizing the plant density of the row crop being grown. As a result, the pneumatic tires to be used in the sprayers vehicles have a narrow section width and a high aspect ratio so that the tire can travel within the intra-row space.

[0015] The sprayers vehicles often operate under heavy loads and on diverse terrains, such as mud, loose soil, and uneven ground and slopes. However, the traditional sprayer tires do not provide adequate grip for such terrains, leading to slippage and insufficient traction while operating on such terrains. Particularly, the traditional sprayer tires fail to evenly distribute the pressure inside the tire, especially on slopes. This is more prominent when the slope is more than 32% with respect to the ground surface. Higher gradient leads to uneven weight distribution causing the sprayers vehicles to deviate from the track. The deviation of the vehicle leads to damage of the crop which in turn decreases the crop yields. The deviation of vehicle may also risk the safety of rider.

[0016] Thus, there is a need for tires that offer superior load-bearing capacity, enhanced traction, and better grip on uneven ground.

[0017] To this end, the tire configuration of a vehicle tire is described herein. In an embodiment, the tire configuration may be modified to overcome the above-described problems associated with handling of vehicles, such as sprayers along with safety of the rider.

[0018] In accordance with an embodiment of the present subject matter, a pneumatic tire comprises a tread portion and pair of sidewall portions on either side of the tread portion. Each of the sidewall portion comprises a bead portion at a distal end of the respective sidewall portions. Further, the tread portion comprises a central region having a first axial width and a pair of adjoiningregions on either side of the central region. The first axial width of the central region is in a range of about 0.48 to 0.53 of a total axial width of the tread portion. The central region has a first radius of curvature in a range of 600 mm to 850 mm. The pair of adjoining regions have a second radius of curvature in a range of 400 mm to 600 mm. Furthermore, the pneumatic tire comprises a carcass having at least one carcass ply that extends from one of the bead portion to the other bead portion through the tread portion and the pair of sidewall portions. The carcass ply has a ply angle with respect to tire circumference direction ranging from 82 degrees to 85 degrees. The pneumatic tire further comprises a plurality of belts that are disposed radially outside the carcass and inside the tread portion, wherein a belt from amongst the plurality of belts, has a belt angle with respect to tire circumference direction ranging from 24 degrees to 26 degrees. Each of the sidewall portions includes an additional rubber layer.

[0019] Thus, the present subject matter discloses the tire configuration, to improve the traction of the tire, through lower shoulder drop and additional sidewall support. The lower shoulder drop provides a high contact area between the tire tread surface and the ground. It also improves traction area towards shoulder region, thus, aiding grip on ground with high slopes which in turn improves stability. Further, the additional rubber at the sidewall improves the lateral stiffness of the tire.

[0020] These and other advantages of the present subject matter would be described in greater detail in conjunction with the following figures.

[0021] The above-described aspects relating to tire tread and configuration for the tire tread are further described with reference to Figures 1 to 5. It should be noted that the description and figures merely illustrate the principles of the present subject matter along with examples described herein and should not be construed as a limitation to the present subject matter. It is thus noted thatvarious arrangements may be devised that, although not explicitly described or shown herein, describe the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[0022] Fig. 1 a illustrates perspective view of pneumatic tire 100, in accordance with an embodiment of the present subject matter.

[0023] As shown in Fig. 1 a, the pneumatic tire 100 comprises a tread portion 102 which comes in contact with the ground during operation. A plurality of lugs 104 are arranged on the tread portion 102 throughout the circumference of the tire 100. Further, the tire 100 comprises a pair of sidewall portions 106 on either side of the tread portion. Each of the sidewall portions 106 comprises a bead portion 108 at a distal end of the respective sidewalls. The sidewall portion 106 can thus be understood to be the part of the tire 100 located between the tread portion 102 and the respective bead portion 108.

[0024] In accordance with an embodiment of the present subject matter, the tread portion 102 of the pneumatic tire 100 is configured to provide a high contact area between the tread surface and the ground as will be explained subsequently in reference to Fig.2 that depicts the construction of the tread portion 102 of the pneumatic tire 100.

[0025] Fig. 1 b illustrates front view of the tire tread 102 of the pneumatic tire 100, in accordance with another embodiment of the present subject matter.

[0026] As shown in Fig. 1 b, the plurality of lugs 104 are arranged on the tire tread portion 102. Each lug 104 protrudes from a bottom surface 110 of the tread portion 102 in a radially outer direction of the tire 100. Further, each lug 104 has a radial height corresponding to the non-skid depth of the tire and extending from the road contacting surface 102 to the bottom surface 110 of the tread portion. In an example, the radial height is about 0.16 to 0.2 timesthe overall diameter of the tire in an unloaded state. The lugs 104 are alternately arranged at given intervals in the circumferential direction of the tire 100 on one side and on the other side with respect to the equatorial plane of the tire 100. The lugs 104 engage with the mud or soil when the tire is operated in the field. In engaging with the mud or soil the lugs provides the necessary traction to allow the longitudes movement of the tire during its rotation.

[0027] Fig. 2 illustrates a cross section of the pneumatic tire, in accordance with an implementation of the present subject matter.

[0028] As shown in Fig. 2, the tread portion 102 has a central region 1 12 and a pair of adjoining regions 114 on either side of the central region 112. In an example embodiment, the central region 112 may have a first axial width TW1 , wherein the first axial width TW1 is in range of about 0.48 to 0.53 of a total axial width TW of the tread portion. The tread portion 102 is defined by a first radius of curvature R1 in the central region 112 and a second radius of curvature R2 in the adjoining regions 114. The first radius of curvature R1 and a second radius of curvature R2 form a tire tread curvature for the tread portion 102.

[0029] In an example embodiment, the first radius of curvature R1 is in range of 600 mm to 850 mm. Similarly, in an example embodiment, the second radius of curvature R2 is in range of 400 mm to 600 mm. The second radius of curvature R2 may be directly proportional to the total axial width TW of the tread portion 102.

[0030] In an example embodiment, a shoulder drop D1 may be affected by change in the second radius of curvature R2. The shoulder drop D1 may refer to the vertical distance from the center of the tread of the tire 100. In accordance with example implementation of the present subject matter, the shoulder drop D1 may be about.06 to 0.08 times the height H of a tire section,i.e., height of the pneumatic tire 100. In one example, the shoulder drop D1 may be 0.07383 times the height H of a tire section.

[0031] A lug end D2 may be disposed substantially at the edge of the tread portion 102. In an example, the lug end D2 from the shoulder drop D1 may be 0.251 times the height H of the tire section.

[0032] As will be understood, a higher shoulder drop D1 provides smaller contact area between the tread portion 102 and the ground, whereas a lower shoulder drop D1 provides larger contact area between the tread portion 102 and the ground. The contact area between the tread portion and the ground during the operation may influence the overall performance of the tire 100, such as its handling and stability, especially on gradient surfaces. The contact area between the tread portion 102 and the gradient surface allows higher contact area at lower air pressure inside the tire 100 thus, improving the traction of the tire on gradient surfaces. In accordance with example implementation of the present subject matter, the shoulder drop D1 is configured to be in the range of about 0.06 to 0.08 times the height H of a tire section so that an adequately large contact area is maintained. As explained previously, a larger contact area is desirable for vehicles, such sprayers that operate on irregular terrains.

[0033] In one example, a distance W between a center of one bead portion 108 to another lies in range from 0.91 to 0.962 times a distance SW between a center of one sidewall portion 106 to another. As will be understood, in accordance with example implementation of the present subject matter, the each of the sidewall portions 106 is configured to have a reduced curvature from the lug end to the corresponding bead portion corresponding to the reduction in curvature of the of the tread portion 102.

[0034] Fig. 3 illustrates a cross sectional view of the pneumatic tire 100, in accordance with yet another embodiment of the present subject matter.

[0035] As shown in Fig. 3, the tire 100 includes at least a carcass having at least one carcass ply 1 16 extending from one of the bead portions 108 to the other bead portion through the tread portion 108 and the pair of sidewall portions 106. The carcass ply 116 typically consists of cords, which are strands of material, such as nylon, polyester, rayon, or steel, that are coated with rubber and oriented in a specific direction relative to the circumference of the tire.

[0036] In one example embodiment, the tire 100 includes a plurality of belts 118 disposed radially outside the carcass and inside the tread portion 102. The belt 118 maintains the shape of the tread portion. The carcass plies 116 and the belts 118 provide structural strength to the tire 100 and also maintain its shape under the stress or load bearing. The specific number of belt layers and the carcass plies may be chosen based on the specific application or requirements of the tire.

[0037] In an example embodiment, each of the sidewall portions 106 may include an additional sidewall component 120. In one example, the additional sidewall component 120 may be a rubber layer. The additional sidewall component 120 may be included to increase the lateral stiffness of the tire 100, especially on gradient surfaces.

[0038] Fig. 4 illustrates a side cross sectional view of the pneumatic tire, in accordance with yet another implementation of the present subject matter.

[0039] As shown in Fig. 4, the carcass ply 116 is oriented at a specific ply angle p with respect to the tire circumference direction. Similarly, the belts 118 are oriented at a specific belt angle a with respect to the tire circumference direction. The ply angle p and the belt angle a are usually measured from the tire centerline M. Further, the angle at which the plies and the belts are oriented on the carcass affects the lateral stiffness of the tire 100.

[0040] In one example embodiment, the ply angle p with respect to tire circumference direction lies in range between 82 degrees to 85 degrees. In one example embodiment, the belt angle a with respect to tire circumference direction lies in range between 24 degrees to 26 degrees. The orientation of the ply angle p and the belt angle a in the aforesaid ranges improves the lateral stiffness and traction of the tire 100, especially on the gradient surface.

[0041] Fig. 5 illustrate a contact area of the pneumatic tire 100 with respect to the ground under different loads and pressure using Finite Element Analysis (FEA) and physical testing.

[0042] In an exemplary embodiment, the pneumatic tire 100 was tested to verify contact patch. In the contact patch test, the tire footprint comparison is done based on the Finite Element Analysis (FEA) and physical testing. The FEA analysis is used to predict and understand how the object may behave under various physical conditions. The results of the test conducted for the pneumatic tire 100 are presented in Table 1.Table 1

[0043] The result confirmed that the contact area and lateral stiffness of the pneumatic tire 100 with respect to the ground are better compared to a conventional tire for which the contact length is typically 620 millimeters (mm), contact width is typically 328 millimeters (mm), and lateral stiffness is typically 36.01 kilograms per millimeters (kg / mm).

[0044] The result confirmed that the contact area and lateral stiffness of the pneumatic tire 100 with respect to the ground are better compared to a conventional tire at STD load of 5450 kg & Pressure 46 Psi.

[0045] Although implementations for improving lateral stiffness and traction of the tire are described, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features are disclosed as implementations.

Claims

I / We claim:

1. A pneumatic tire comprising: a tread portion and pair of sidewall portions on either side of the tread portion, each of the sidewall portions comprising a bead portion at a distal end of the respective sidewall portions, the tread portion comprising a central region having a first axial width (TW1 ) and a pair of adjoining regions on either side of the central region, the first axial width (TW1 ) of the central region being in a range of about 0.48 to 0.53 of a total axial width (TW) of the tread portion; wherein the central region has a first radius of curvature (R1 ) in a range of 600 mm to 850 mm; wherein the pair of adjoining regions have a second radius of curvature (R2) in a range of 400 mm to 600 mm; a carcass having at least one carcass ply extending from one of the bead portion to the other bead portion through the tread portion and the pair of sidewall portions; wherein the carcass ply has a ply angle (0) with respect to tire circumference direction ranging from 82 degrees to 85 degrees; a plurality of belts disposed radially outside the carcass and inside the tread portion; wherein a belt from amongst the plurality of belts has a belt angle (a) with respect to tire circumference direction ranging from 24 degrees to 26 degrees; and wherein each of the sidewall portions includes an additional rubber layer.

2. The tire as claimed in claim 1 , wherein the second radius of curvature (R2) is directly propositional to the total axial width (TW) of the tread portion.

3. The tire as claimed in claim 1 , wherein a distance (W) between a center of one bead portion to another lies in range from 0.91 to 0.962 times a distance (SW) between a center of one sidewall portion to another.

4. The tire as claimed in claim 1 , wherein a shoulder drop (D1 ) is 0.07383 times the height (H) of a tire section.

5. The tire as claimed in claim 1 , wherein a plurality of lugs are provided on the tread portion; wherein, each lug extends radially outwards, over a radial height , from a bottom surface of the tread portion.

6. The tire as claimed in claim 5, wherein the plurality of lugs are alternately arranged along a tire circumferential direction on both sides in the tire width direction.

7. The tire as claimed in claim 1 , wherein a lug end (D2) is 0.251 times the height (H) of the tire section.

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