TECHNICAL FIELD
The present invention relates to geometry of tyre tread, particularly to optimization of the geometiy of discrete tread elements of pneumatic tyres to improve the ability of the tyre tread to resist stone trapping.
BACKGROUND ART
In a pneumatic tyre, a circumferential belt layer and an auxiliary belt layer made of organic fiber cord are provided at an inner side of a groove in shoulder portion in a radial direction of the tyre. With this configuration, the periphery of the groove at the edge of the shoulder portion is reinforced, which allows reduction of a crack in the bortom of the groove.
If a projection is provided in the groove, the capacity of drainage when a vehicle is driven in the rain reduces due to reduced space. To increase the drainage, an increase in width of the groove is likely a solution. However, this may lead to a pebble being trapped in the grooves when the tyre goes through a surface where stones, pebbles or debris are present thereby developing a plurality of hairline cracks at a stress concentrating point in the grooves. Since a tension is applied at the bottom portion of the grooves in the direction of a rotary axis of tyre, there are produced stress concentration at the end of cracks, resulting in promoting the growth of cracks produced in longitudinal direction. In this manner, the cracks propagate gradually with the use of a tyre, such as tread separation, sipping water in to the carcass, premature wear and overall decrement of tyre durability.
Therefore, a need exists for designing the tyre tread in order to make it less prone to stone trapping.
SUMMARY OF THE INVENTION
Before the present system(s) are described, it is to be understood that this application is not limited to the particular system(s) described, as there can be

multiple possible embodiments, which are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular implementations or versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to geometry of a tyre tread. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[007] An object of the present invention is to create a tyre tread geometry which is less prone to stone trapping in the pattern of tyre which will result in lesser groove cracks and improved overall tyre durability.
[008] The present invention relates to vehicle pneumatic tyre and more specifically to a tread pattern for passenger vehicle tyres which is subjected to debris, stones present on the roads or when the vehicle is operated on broken roads frequently. The tread of a pneumatic tyre typically comprise of plurality of load bearing tread block elements separated by a network of grooves. Further, the gap between the tread block elements are kept at optimum level to provide desired mileage from the tyre.
[009] Yet another object of the present invention is to provide a pneumatic tyre with groove surfaces which are in front of each other and are kept at different angles to generate uneven forces for ejecting the stones.
BRIEF DESCRIPTION OF THE DRAWINGS
[010] The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustration of the present subject matter, an example of construction of the present subject matter is provided as figures; however, the invention is not limited to the specific method and system disclosed in the document and the figures.
[011] It is therefore to be noted that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting its scope, for the invention may admit to other equally effective embodiments.

[012] Figure 1 is the top view of the tread portion of a pneumatic tyre as per the present invention.
[013] Figure 2 is the front view of the tread portion cross section along the line X-X of Figure 1.
[014] Figure 3 is a detailed diagram of the Part A of Figure 2.
[015] Figure 4 is a perspective view of unmodified tyres versus modified tyres as per the present invention.
DETAILED DESCRIPTION
[016] Some embodiments of this disclosure, iilustrating all its features, will now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein, the singular forms "a," "an," and "the" include plural references unless the context elearly dictates otherwise. Although any system similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary system are now described. The disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. The disclosed embodiments can be used as standalone or in combination. Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments described, but is to be accorded the widest scope consistent with the principles and features described herein.
[017] As shown in Figure 1, a pneumatic tyre 1 has a tread surface 20 which is part of a tread portion 40, formed circumferentially on the outer most side (in radial direction) of the tyre. The pneumatic tyre has a groove region 30 which forms a tread pattern of the tyre on surface of the tread portion 20. There are at least four grooves 30 present circumferentially on the tread surface 20. The

grooves 30 divide the tread portion in at least fl ve parts called ribs. The rib 11 is located centrally of the groove region. The ribs adjacent to the centrally located rib 11 is 11,12 and the outer most rib which is also referred to as shoulder rib is 11,13.
[018] Figure 2 is the cross-section view of tread portion of tyre 1 along the line X-X. A belt layer 60 is provided in bottom side of the tread portion 40 as reinforcement for carcass 65. The carcass is consisting of body ply and inner liner, which enclose the air required for load carrying.
[019] As shown in Figure 3, edges of the bottom groove are made as round as possible to minimize the stress concentration at the grooves. The radius (a) of the edges can be in the range of 0.8 mm to 1.2 mm depending on the width of the tread portion 20. Further, the width of bottom groove is kept at least 2 times smaller than the width at surface 30 to restrict stones from reaching at the bottom. The depth of the groove can be up to 10 mm. The groove may have variable width to further reduce the chances of stones getting stuck in the grooves. Further, the width of the tread portion may vary in the range of 98 mm to 130 mm.
[020] According to one embodiment of the present invention, the groove surfaces which are in front of each other are kept at different angles to generate uneven forces for ejecting the stones.
[021] Figure 4 shows a comparative visual of unmodified tyres and modified tyres in accordance with the present invention. The unmodified tyres were placed on one side of a vehicle and the modified tyres on the other side. The tyres were tested for 1000 kilometers and it was found that the modified tyres had 80 percent to 90 percent less stones trapped than the unmodified tyres.
[022] The invention has been described with reference to various specific and illustrative embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention.
[023] For instance, while the various designs have been described with respect to structure and constructional features of the preferred embodiments of the invention, novel aspects of the embodiments described may be incorporated in

other designs. Also, the description is made with respect to exemplary embodiments only and it should be understood that the arrangement of many of the design blocks and components may be changed without departing from the scope of an appended claim. Also, it should be understood that in alternate embodiments claimed in the claims, many of the components described with respect to the exemplary embodiments may be withheld or may be replaced by equivalent structures. Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

WE CLAIM:
1. A pneumatic tyre comprising:
a tread portion having a tread surface located circumferentially on the outer most side of the tyre;
a groove region forming a tread pattern on the surface of the tread portion of tyre, the groove region having at least four grooves that divide the tread portion in at least five ribs; and
edges of the groove bottom made round so as to minimize stress concentration at the grooves.
2. A pneumatic tyre according to claim 1 wherein the edges of the groove bottom have a radius in the range of 0.8 mm to 1.2 mm depending on the width of the tread portion.
3. A pneumatic tyre according to claim 2, wherein the width of the tread portion may vary in the range of 98 mm to 130 mm.
4. A pneumatic tyre according to claim 2, wherein the edges of the groove bottom have a radius of 1 mm.
5. A pneumatic tyre according to claim 1, wherein the width at the surface of the tread portion is 2 times the width of the groove bottom.
6. A pneumatic tyre according to claim 1, wherein the width at the surface of the tread portion is 2.5 times the width of the groove bottom.
7. A pneumatic tyre according to claim 1, wherein the depth of the groove bottom is 10 mm.
8. A pneumatic tyre according to any of the preceding claims, wherein the groove surfaces which are in front of each other are kept at different angles to generate uneven forces for ejecting any stones trapped in the grooves.
9. A pneumatic tyre according to any of the preceding claims, wherein the tyre is used in a passenger vehicle.

10. A pneumatic lyre according to any of the preceding claims, wherein the tyre is used in a heavy-duty vehicle.