FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13)
1. Title of the invention: NOISE REDUCTION IN VEHICLE TIRE
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian RPG HOUSE, 463, Dr. Annie Besant Road, Worli, Mumbai, Maharashtra 400030, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates, in general, to vehicle tires and,
particularly but not exclusively, to vehicle tires having treads.
BACKGROUND
[0002] Tires support load of a vehicle and impact handling, drivability, and safety
of the vehicle. A tire has a crown or center region, a shoulder region and beads on either side of the center region. In an example, the center region may be understood as outer region of the tire formed along complete circumference of the tire and spreads along width of the tire. Further, the center region contacts with surface during rotation. The beads may be understood as edges of the tire. The beads contact with wheel during mounting of the tire. The shoulder region is portion of the tire joining the center region and the beads of the tire.
[0003] Vulcanized and treated rubber on the center region and shoulder region of
the tire is a tread of the tire. The tread is often carved in diverse configuration by way of tread blocks, tread grooves, tread voids, wear bar, and the like. The configuration the tread affects contact and interaction of the tire with road and thus affects traction of the vehicle and noise generated during the interaction of the tire with road surface. Hence, the tread configuration has a crucial role in tire life, vehicle maneuvering, noise-free driving, safety, and ease of driving.
BRIEF DESCRIPTION OF DRAWINGS
[0004] 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.
[0005] Figure 1 illustrates a conventional design of a tire tread pattern illustrating
lateral grooves in circumferential tread rows of a shoulder tread region.

[0006] Figure 2 illustrates a width of the lateral grooves in circumferential tread
rows of the shoulder tread region according to the conventional design of the tire tread
pattern.
[0007] Figure 3 illustrates a height of the lateral grooves in circumferential tread
rows of the shoulder tread region according to the conventional design of the tire tread
pattern.
[0008] Figure 4 illustrates a schematic of the tire illustrating circumferential
grooves in the shoulder tread region according to the conventional design of the tire
tread pattern.
[0009] Figure 5 illustrates schematics of a tire with a tread pattern illustrating
lateral grooves in circumferential tread rows of a shoulder tread region of the tire, in
accordance with an implementation of the present subject matter.
[0010] Figure 6 illustrates schematics of the tire with the tread pattern illustrating
a width of the lateral grooves in circumferential tread rows of the shoulder tread region
of the tire, in accordance with an implementation of the present subject matter.
[0011] Figure 7 illustrates schematics of the tire with the tread pattern illustrating
a height of the lateral grooves in circumferential tread rows of the shoulder tread region
of the tire, in accordance with an implementation of the present subject matter.
[0012] Figure 8 illustrates a design of a tread pattern of a tire depicting
circumferential grooves and lateral grooves, according to an example implementation
of the present subject matter.
DETAILED DESCRIPTION
[0013] In vehicles, there are two major sources of noise generated during motion
of a tire incorporated in a vehicle along a surface or road. One is a propulsion system of the vehicle, such as a combustion engine along with a power transmission shaft attached to it. Second, during motion of the vehicle, tread region of the tire contacts with surface of the motion. Upon contact with the surface ambient air gets trapped

between grooves of the tire treads and the surface. The trapping of the air and improper air channeling generates noise in the tire during motion.
[0014] Noise generated from the tire significantly depends on tire tread pattern
design, tread compound, tire construction or sidewall structure. Air pumping due to the air compression/expansion in the tread grooves is the major contributor of pattern noise in the tire. So, to minimize this noise, volume of air entering in the tread grooves should be minimized. In this context, tire design parameters are very critical and any deviation from any of them may lead to trade off in other performance parameters which is not acceptable in some cases. Conventionally, diverse tread patterns have been designed. However, conventional tread patterns amount to generation of noise in the tire. Some tread patterns are designed with multiple grooves to enhance air channeling. However, with increase in grooves, surface of the tire in contact with the surface during motion is reduced, amounting to poor braking of the vehicle. Thus, affecting maneuvering and safety of the vehicle.
[0015] Referring to Figure 1, a conventional design of a tire tread pattern
illustrating lateral grooves in circumferential tread rows of a shoulder tread region is illustrated. A tire 100 having a center tread region 102 and a shoulder tread region 104 on either side of the center tread region 102 is illustrated. A circumferential tread row comprises multiple transverse or lateral grooves 106. A tire tread pattern is formed by plurality of circumferential tread rows separated by circumferential grooves 108. Circumferential 108 and lateral grooves 106 formed along a circumference of a tire 100 forms tread blocks or pitches. Thus, a circumferential tread row includes multiple tread blocks or pitches. In a conventional design of tire 100, tread pattern of the tire 100 is such that an angle created by edges 110 of the lateral grooves 106 at the surface of the tire 100 coincide with an angle created by the leading edge of contact patch that the tire 100 makes with road surface during movement. Such tread pattern creates a resonance frequency during movement of the tire 100 on the road surface which generates noise. According to the conventional design of tread pattern as illustrated in

Figure 1, first and second edges 110 of a lateral groove 106 at a surface of the tire 100
are sharp. This causes angles created by first and second edges 110 of the lateral
groove 106 at the surface of the tire 100 to coincide with an angle created by a leading
edge of contact patch that the tire 100 makes with road surface during movement.
[0016] Further, conventional tread pattern of the tire 100 is such that volume of
lateral grooves in a tread region of the tire 100 is large enough to allow large volume of air to circulate therethrough. This leads to generation of noise during movement of the tire 100 on a road surface. For instance, referring to Figure 2, a width W of the lateral groove 106 is large enough to make a space available for the circulation of large volume of air. In an example, width W of the lateral groove is 10 mm.
[0017] Further, Figure 3 illustrates a height of the lateral grooves 106 in
circumferential tread rows of the shoulder tread region 104 according to the conventional design of the tire tread pattern. Figure 3 shows that a tie bar height h1 of a lateral groove 106 is large, for example, 50% of a non-skid depth h2 of the tire 100. The non-skid depth h2 of the tire 100 may be understood as a height h2 of the lateral grooves 106 from the surface of the tire 100. Whereas a tie bar height h1 of the lateral groove 106 may be understood as a depth h1 of the cavity inside the lateral groove 106 along length of the lateral groove 106. In an example, the depth h1 of the cavity inside the lateral groove 106 along a length of the lateral groove 106 is 25%-50% of a height h2 of the lateral groove 106 from the surface of the tire 100. This also provides large space for the air to flow, leading to generation of noise.
[0018] Furthermore, circumferential grooves 108 in the tread region of the tire 100
also provide a channel for the air to circulate without interference during movement of the tire on the road surface leading to the generation of noise. For instance, referring to Figure 4, a conventional design of a tire tread pattern illustrating circumferential grooves 108 in a tread region of the tire 100 is illustrated. According to the conventional design of tread pattern as illustrated in Figure 4, circumferential grooves 108 in the shoulder tread region 104 provides channels for the air flow during

movement of the tire 100 on a road surface. Specially, tread pattern in the shoulder
region 104 of the tire 100 provides more space for the air to circulate therethrough.
[0019] To this end, the present subject matter provides a tire for a vehicle which
produces less noise during movement over a road surface, the tire may be modified to
overcome the above-described problem associated with air channeling and consequent
noise generation during motion of the vehicle on the road surface. The modifications
to the conventional tires for the purpose of noise reduction as described and claimed
herein do not adversely impact any other performance parameter of the tire. As
discussed above, changes in performance parameter of the tire are undesired given the
critical role of the tires and in that the present invention as a technical advance.
[0020] In accordance with an embodiment of the present subject matter, a tire for
noise reduction is disclosed. The tire has a center tread region and a shoulder tread region on either side of the center tread region. The tire includes at least one circumferential groove along a length of the tire in the shoulder tread region of the tire. The tire further includes a plurality of lateral grooves in the shoulder region. Each of the plurality of lateral grooves in the shoulder tread region comprises a chamfer along each of two edges of the respective lateral groove.
[0021] Thus, the present subject matter discloses the tire tread configuration with
reduced tire noise. The tread configuration disclosed by the present subject matter has a chamfer at the surface of the tire along each edge of the grooves in the shoulder tread region, such that the occurrence of resonance frequency that happens due to the sharp edges of the lateral grooves may be prevented. Thus, the generation of noise because of resonance frequency may be avoided. Hence, the tire generates reduced noise including cabin noise and pass by noise when rolled over a road surface.
[0022] The above and other features, aspects, and advantages of the subject matter
will be better explained with regard to the following description and accompanying figures. 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 understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and examples thereof, are intended to encompass equivalents thereof. Further, for the sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components.
[0023] Figures 5 illustrates schematics of a tire with a tread pattern illustrating
lateral grooves in circumferential tread rows of a shoulder tread region of the tire, in accordance with an implementation of the present subject matter. Figure 6 illustrates schematics of the tire with the tread pattern illustrating a width of the lateral grooves in circumferential tread rows of the shoulder tread region of the tire, in accordance with an implementation of the present subject matter. Figure 7 illustrates schematics of the tire with the tread pattern illustrating a height of the lateral grooves in circumferential tread rows of the shoulder tread region of the tire, in accordance with an implementation of the present subject matter. Figure 8 illustrates a design of a tread pattern of a tire depicting circumferential grooves and lateral grooves, according to an example implementation of the present subject matter. For the sake of ease of explanation, Figures 5, 6, 7 and 8 are explained all together.
[0024] In an implementation of the present subject matter, the tire 100 has a center
tread region 102 and a shoulder tread region 104 on either side of the center tread region 102. More specifically, the tire 100 may have two shoulder tread regions 104 with a center tread region 102 between the two shoulder tread regions 104. The center 102 and the shoulder 104 tread regions may include different tread patterns. At least one circumferential tread row is included in the center tread region 102 having plurality of pitches and at least one circumferential tread row in the shoulder tread region 104 having plurality of pitches. As illustrated, the tire tread pattern is formed by plurality of circumferential tread rows separated by circumferential grooves 108.

The circumferential grooves 108 may be understood as groove in solid tread portion of the tire 100 along circumference or length of the tire 100. The tire 100 comprises at least one circumferential groove 108 along circumference or length of the tire 100 in the shoulder tread region 104 of the tire 100. More specifically, the shoulder tread region 104 formed on both sides of the center tread region 102 comprises at least one circumferential groove 108 on each side of the center tread region 102. The tire tread pattern also includes lateral or transverse grooves 106. In an example, the tire 100 comprises a plurality of lateral grooves 106 in the shoulder tread region 104. The lateral or transverse grooves 106 may be understood as grooves in the solid tread portion of the tire 100 along tread width of the tire 100. A lateral groove 106 extends from a circumferential groove 108 to another circumferential groove 108 along a width of the tire 100. In an example, at least one groove from amongst the plurality of lateral grooves is in a zigzag shape.
[0025] In an example implementation of the present subject matter, referring to
Figure 5, each of the plurality of lateral grooves 106 comprises a chamfer 112 along each of two edges 110 of the respective lateral groove 106. A chamfer 112 may be understood as a slanted profile created at each of the two edges 110 of the lateral grooves 106 at the surface of the tire 100. This is opposed to the conventional design pattern of lateral groove 106 illustrated in Figure 1, where the edges 110 of the lateral grooves 106 are sharp. In an example, a width of a chamfer 112 is in a range of 0.5-2.5 mm. In another example, the width of the chamfer 112 is 1 mm. Presence of chamfers 112 at the edges 110 of the lateral grooves 106 along the surface of the tire 100 creates interference in a circulation of air passing through the lateral grooves 106 and prevents the creation of resonance frequencies during a movement of the tire 100 on a road surface. This results in reduction of noise generated during movement of the tire 100 on the road surface.
[0026] In an example, referring to Figure 6, a width W of each of the plurality of
lateral grooves 106 in the shoulder tread region 104 is in a range of 6-12 mm. In

another example, the width W of each of the plurality of lateral groove 106 in the
shoulder tread region 104 is 8 mm. In the conventional design of tire tread pattern as
shown in Figure 2, the width W of the lateral groove 106 in the shoulder region 104 is
around 10 mm. Thus, the tire 100 disclosed herein provides a reduction of 20 % in a
width W of each of the plurality of lateral grooves 106 in the shoulder tread region
104 of the tire 100 as compared to the conventional tire tread pattern. In another
example, the tire 100 disclosed herein provides a reduction of 10-40 % in the width W
of each of the plurality of lateral grooves 106 in the shoulder tread region 104 of the
tire 100 as compared to the conventional tire tread pattern. The lateral grooves 106
having small width provides less space for the air to circulate therethrough during
movement of the tire 100 on the road surface, resulting in a reduction of tire noise.
[0027] In another example implementation of the present subject matter, referring
to Figure 7, a height of the lateral grooves 106 in circumferential tread rows of the
shoulder tread region 104 of the tire 100 is depicted. A depth h1 of a cavity inside each
of the plurality of lateral grooves 106 along a length of the respective groove is 75 %
of a height h2 of the lateral groove 106 from a surface of the tire 100. A depth h1 of
the cavity inside each of the plurality of lateral grooves 106 along a length of the
respective groove 106 is known as tie bar height h1. While a height h2 of a lateral
groove 106 from the surface of the tire 100 is known as non-skid depth h2 of the tire
100. Thus, a tie bar height h1 of a lateral groove is 75% of a non-skid depth h2 of the
tire 100. As opposed to this, in a conventional tire tread pattern illustrated in Figure 3,
a tie bar height h1 of a lateral groove 106 is large, for example, 50% of a non-skid
depth h2 of the tire 100. Thus, reduction in depth of the lateral groove 106 reduces the
volume of the cavity defined therein and provides less space for the air to flow, leading
to reduced noise generation during movement of the tire 100 on the road surface.
[0028] In an implementation of the present subject matter, referring to Figure 8, a
design of a tread pattern of the tire 100 depicting circumferential grooves 100 and lateral grooves is illustrated.

[0029] A tread block is formed between two adjacent lateral grooves 106 in a
circumferential tread row formed between two adjacent circumferential grooves 108. Thus, circumferential 108 and lateral 106 grooves in the solid tread portion form pitches or tread blocks and multiple pitches together form a circumferential tread row. As stated above, each of the at least one circumferential tread row in the center tread region 102 and at least one circumferential tread row in the shoulder tread region 104 has plurality of pitches. The pitches in a circumferential tread row may be separated by lateral grooves 106. In an example, a number of circumferential tread row in the tire is in a range of 3-4. In an example, the number of tread blocks or pitches in a circumferential tread row in the center tread region 102 and in a circumferential tread row in the shoulder tread region 104 may be same or different. In another example, number of pitches or tread blocks in a circumferential tread row defined through the circumferential grooves 108 and the plurality of lateral grooves 106 in the shoulder region is in a range of 1-2. In another example, the number of lateral grooves in a pitch or tread block is in a range of 1-2.
[0030] In an example, number of circumferential grooves 108 in the shoulder tread
region is in a range of 1-2. In another example, the number of circumferential grooves in the center tread region is in a range of 1-2.
[0031] In an example, the at least one circumferential groove 108 along the length
of the tire 100 in the shoulder tread region 104 comprises a plurality of rectangular protrusions 116, 114. The rectangular protrusions 114, 116 are also termed as stone ejectors. The rectangular protrusions 114, 116 may be formed of the same material as used in manufacturing of tire. In an example, a distance between two consecutive protrusions 114, 116 from amongst the plurality of protrusions 114, 116 is in a range of 3 mm to 8 mm. In another example, each of a height and a width of each of the plurality of rectangular protrusions 114, 116 is in a range of 2 mm to 6 mm. In an example, a plurality of rectangular protrusions 114, 116 comprises a plurality of first rectangular protrusions 114 and a plurality of second rectangular protrusions 116. The

plurality of first rectangular protrusions 114 and the plurality of second rectangular
protrusions 116 are arranged alternatively in the respective circumferential groove.
[0032] In an example, each of the plurality of first rectangular protrusions 114 are
formed at a point of intersection of a lateral groove 106 from amongst the plurality of lateral grooves 106 with respective circumferential groove 108. Each of a plurality of second rectangular protrusions 116 is formed between point of intersections of two adjacent lateral grooves 106 with respective circumferential groove 108. In an example, a length of a first rectangular protrusion 114 is greater than a length of a second rectangular protrusion 116. In an example, a length of each of the plurality of first rectangular protrusions 114 is in a range of 10 mm to 14 mm, and a length of each of the plurality of second rectangular protrusions 116 is in a range of 4 mm to 8 mm. Configuration of rectangular protrusions 114, 116 is such that a first protrusion is formed at a point where a lateral groove 106 from amongst the plurality of lateral grooves 106 meet with a circumferential groove 108 and has a length greater than a length of a second rectangular protrusion that is formed between two lateral grooves. Thus, rectangular protrusions 114, 116 or stone ejectors act as a blocker for the air passing from the lateral grooves 106 to circumferential grooves 108 and avoids air channeling through the lateral 106 and circumferential grooves 108. This prevents the generation of noise during movement of the tire 100 on the road surface. Furthermore, the configuration of the rectangular protrusions 114, 116 in a circumferential groove 108 in the shoulder tread region 104 also prevents trapping of stones or other similar substances in the circumferential grooves 108.
[0033] As a result of an example implementation of the present subject matter, the
tire 100 incorporated in a vehicle, when rolled over a road surface along the movement of the vehicle, pass by noise are significantly reduced by 1 % to 5 % respectively as compared to the conventional tires. Further, because of reduced noise, less vibration are produced resulting in a more comfortable ride for the passengers which is.

[0034] Although implementations of a tire 100 are described, it is to be understood
that the present subject matter is not necessarily limited to the specific features of the systems described herein. Rather, the specific features are disclosed as implementations for the tire 100.

I/We Claim:
1. A tire 100 for noise reduction, the tire 100 comprising:
at least one circumferential groove 108 along a length of the tire 100 in a shoulder tread region 104 of the tire 100;
a plurality of lateral grooves 106 in the shoulder region 104;
wherein each of the plurality of lateral grooves 106 comprises a chamfer 112 along each of two edges 110 of the respective lateral groove 106.
2. The tire 100 as claimed in claim 1, wherein a width W of each of the plurality of lateral grooves 106 is in a range of 0.5 mm to 2.5 mm.
3. The tire 100 as claimed in claims 1 or 2, wherein a depth h1 of a cavity inside each of the plurality of lateral grooves 106 along a length of the respective groove is 75 % of a height h2 of the lateral groove 106 from a surface of the tire 100.
4. The tire 100 as claimed in claim 1, wherein the at least one circumferential groove 108 along the length of the tire 100 in the shoulder tread region 104 comprises a plurality of rectangular protrusions 114, 116.
5. The tire 100 as claimed in claim 4, wherein a distance between two consecutive protrusions 114, 116 from amongst the plurality of protrusions 114, 116 is in a range of 3 mm to 8 mm.
6. The tire 100 as claimed in claim 4, wherein each of a height and a width of each of the plurality of rectangular protrusions 114, 116 is in a range of 2 mm to 6 mm.
7. The tire 100 as claimed in anyone of claims 4 to 6, wherein a plurality of rectangular protrusions 114, 116 comprises a plurality of first rectangular protrusions 114 and a plurality of second rectangular protrusions 116 arranged alternatively in the respective circumferential groove 108.

8. The tire 100 as claimed in anyone of claims 4 to 7, wherein each of the plurality of first rectangular protrusions 114 are formed at a point of intersection of a lateral groove 106 from amongst the plurality of lateral grooves 106 with respective circumferential groove 108, and wherein each of the plurality of second rectangular protrusions 116 is formed between point of intersections of two adjacent lateral grooves 106 with respective circumferential groove 108.
9. The tire 100 as claimed in anyone of claims 4 to 8, wherein a length of each of the plurality of first rectangular protrusions 114 is in a range of 10 mm to 14 mm, and wherein a length of each of the plurality of second rectangular protrusions 116 is in a range of 4 mm to 8 mm.
10. The tire 100 as claimed in claim 1, wherein a number of circumferential grooves 108 in the shoulder tread region 104 is in the range of 1-2.
11. The tire 100 as claimed in claim 1, wherein a number of tread blocks defined through the circumferential grooves 108 and the plurality of lateral grooves 106 in the shoulder region 104 is in a range of 40-60.
12. The tire 100 as claimed in claim 1, wherein at least one lateral groove 106 from amongst the plurality of lateral grooves 106 is in a zigzag shape.