Title of Invention

"PNEUMATIC BIAS MOTOR CYCLE AND SCOOTER TYRE WITH BURIED SUB-TREAD HAVING RUBBER COMPOSITION FOR LOW ROLLING RESISTANCE"

Technical Field:

The present invention relates to Pneumatic Bias motor cycle and scooter tyre having a toroidal shape, having a tread, the tread comprising of a cap which is the road contact part and sub-tread part, which is buried in the road touching part. The buried sub-tread comprising of a rubber composition for low hysteresis which will reduce the Rolling Resistance of the tyre. This could also be used to improve the handling characteristics of the entire tyre which has a toroidal shape as a whole.

Background & Prior Art

The present invention relates to Pneumatic Bias motor cycle and scooter tyre having a toroidal shape having a tread, the tread comprising of a cap which is the road contact part and sub-tread part, which is buried in the road touching part. The buried sub-tread comprising of a rubber composition for low hysteresis which will reduce the Rolling Resistance of the tyre. This could also be used to improve the Handling characteristics of the entire tyre which has a toroidal shape as a whole.
To reduce the rolling resistance of Pneumatic Bias motor cycle and scooter tyre some methods are already available in the public domain, like low rolling resistance cap compound usage, tyre weight reduction etc. The present invention is another method to reduce the rolling resistance of bias motor cycle and scooter tyres by a new concept called "Buried-Sub Tread", which is having lower hysteresis than the road touching part 'cap'. The peculiar nature of sub-tread 'low hysteresis' results in reducing the rolling resistance of the above mentioned tyre as well as improves the handling characteristics of the tyre.
Tyre with higher rolling resistance increases the fuel consumption of the vehicle and thus increases the emission of the harmful gaseous materials to the atmosphere, which leads to global warming. Tyre with low rolling resistance reduces the fuel consumption of vehicle and thus the gaseous materials emission too. On a move to reduce the anthropogenic impact on the environment, the current invention of Pneumatic Bias motor cycle and scooter tyre comprising a tread, the tread comprising a cap with sub-

tread which is buried in the road touching part "cap", comprising rubber composition for excellent steering stability, handling characteristics and low rolling resistance leads to enhancement of energy efficiency which reduces the consumption of non-renewable resources and reduces the gaseous materials emission, controls the global warming phenomenon and preserves the non-renewable resources for the upcoming generation.
Dynamic property of the rubber composition, which comprises cap which has a toroidal shape as a whole and with sub-tread which is buried in the road touching part "cap", the terms mentioned later are well known to those having skills in the rubber compounding art.
The loss tangent "Tan 6 @ 30°C" related to dry grip performance, Storage Shear Modulus G'@ 60°C and loss tangent "Tan 5 @ 60°C" are related to Rolling Resistance and Storage Shear modulus G' @ 30°C related to handling.

Detailed Description

The Tyre in the present invention, Pneumatic Bias motor cycle and scooter tyre comprising a tread, the tread comprising a cap and with sub-tread which is buried in the road touching part "cap", buried sub-tread comprising rubber composition for excellent steering stability, handling characteristics and low rolling resistance, which will enhance the above mentioned characteristics of the road touching surface and has a toroidal shape as a whole. The sub-tread which is buried in the cap is having low rolling resistance and low hysteresis than the tread, which will reduce the low rolling resistance capacity of the tyre as a whole.
The sub-tread which is buried in the toroidal shaped road touching part "cap" and having a thickness range of 5 % to 75 % of the total gauge of the tread, ensuring the upper value of the thickness range is limited to the extent that it will not touch the road surface on wearing to the permitted legal limit.'
Tread has a composite structure of road touching surface and has a toroidal shape as a whole "cap" and with sub-tread which is buried in the road touching part "cap" and/or same "cap" composition extending as side wall and/or separate side wall comprising different rubber composition other than cap.

Cap compound composition comprising Natural rubber from 0 to 80 parts per hundred rubber (phr) and/or Solution/Emulsion SBR with or without functionalisation, from 0-100 phr and/or Poly butadiene with or without functionalisation from 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or without coupling agent and/or carbon black with Iodine adsorption value from 36-160 mg/g from 0 to 60 phr, with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr.
Sub-tread compound composition comprising Natural rubber from 0 to 100 phr and/or Solution/Emulsion SBR with or without functionalisation 0-100 phr and/or Poly butadiene with or without functionalization 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or without coupling agent and/or carbon black with Iodine adsorption value from 36-160 mg/g from 0 to 60 phr, with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr.
The description of the invention and drawing:
Pneumatic Bias motor cycle and scooter tyre comprising a tread, the tread comprising a cap and with sub-tread which is buried in the road touching part "cap", buried sub-tread comprising rubber composition for excellent steering stability, handling characteristics and low rolling resistance, which will enhance the above mentioned characteristics of the road touching surface and has a toroidal shape as a whole. The rubber composition of sub-tread compound which is buried in the road touching part "cap" comprising Natural rubber from 0 to 100 phr and/or Solution/Emulsion SBR with or without functionalisation 0-100 phr and/or Poly butadiene with or without functionalisation 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or without coupling agent and/or carbon black with Iodine adsorption value from 36-160 mg/g from 0 to 60 phr with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr.
Tread has a composite structure of road touching surface and has a toroidal shape as a whole "cap" and with sub-tread which is buried in the road touching part "cap" and/or same "cap" compound and/or sub-tread compound composition extending as side wall.and/or separate side wall comprising different rubber composition other than cap and sub-tread and the rubber composition of the "cap" comprising Natural rubber from 0 to 80 phr and/or Solution/Emulsion SBR with or without functionalisation 0-100 phr and/or Poly butadiene with or without functionalisation 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or without coupling agent and/or carbon black with Iodine adsorption value from 36-160 mg/g from 0 to 60 phr with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr.

Figure 1 is the section view of the Pneumatic Bias motor cycle / scooter tyre with buried sub-tread having same "cap" compound composition extending as side wall.
Figure 2 is the section view of the Pneumatic Bias motor cycle / scooter tyre with buried sub-tread having separate side wall comprising different rubber composition other than 'cap' and 'sub-tread' Figure 3 is the partial section view of the Pneumatic Bias motor cycle/ scooter tyre with buried sub-tread.
Figure 4 the section view of the Pneumatic Bias motor cycle/ scooter tyre with buried sub-tread having side wall comprising same rubber composition of 'sub-tread'.
In Figure 1, 2, 3 and 4 'A' is road touching rubber composition has a round shape as a whole called "cap". In Figure 1, 2, 3 and 4 (B' is the low rolling resistance rubber composition part, which is buried in the road touching part "cap" which has round shape as a whole and the thickness is just beneath 'A' in Figure 3 which is up to Non Skid Depth called NSD. 'C in Figure 2 is the rubber composition which is called 'side wall' and is in both the sides of the tyre. In figure 1, 2 and 4 'D' is the rubber coated metals or metal alloys which is called bead . (F' in figure 1, 2 and 4 is the rubber composition which is placed in between carcass and the cap-buried sub-tread combination, hereafter it is called "breaker". 'G' in figure 1, 2 and 4 is ply cords coated with rubber called "outer ply". 'FT in figure 1, 2 and 4 is ply cords coated with rubber called "inner ply". 'G' and 'H' together in figure 1, 2 and 4 are called "carcass". In figure 1 , 2 and 4 T is rubber composition which comes in the bottom layer of the drawings shown called "inner liner". 'J' in figure 1 , 2 and 4 is the fabric material which is coated with rubber called "chafer".
'A' in Figure 3 is the road touching rubber composition which is toroidal shape as a whole called "cap". 'B' in Figure 3 is the rubber composition which is buried in the road touching rubber composition and a toroidal shape as a whole in the pneumatic tyre, and is called "sub-tread", which is having a thickness range of 5% to 75% of the total gauge of the "cap" the upper value not exceeding the "TWI" described below. In figure 3 Tread Wear Indicator "TWI" is the indication which is globally accepted and is known to expert in the field. According to IS 15627:2005 "Tyre shall be considered unsafe for service on road when remaining worn skid depth reaches minimum value of 0.8 mm at any point of the tread circumference"

We Claim:

1, A Pneumatic Bias and motor cycle and scooter tyre having a toroidal shaped part which is touching the road called "tread", the tread comprising a cap and with sub-tread which is buried in the toroidal shaped road touching part "cap", buried sub-tread comprising rubber composition for excellent steering stability, handling characteristics and low rolling resistance, which will enhance the above mentioned characteristics of the toroidal shaped tyre as a whole and the rubber composition of sub-tread compound which is buried in the road touching part "cap" and having the road touching "cap" composition extending as side walls or separate side walls with same or different rubber composition as "cap" and/or "sub-tread";
Cap extending as sidewall or base extending as sidewall or a separate sidewall of different rubber composition;
(A) the road touching part "cap" comprising. Natural rubber from 0 to 80 phr and/or Solution/Emulsion SBR with or without functionalisation 0-100 phr and/or Poly butadiene with or without functionalisation 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or without coupling agent and/or carbon black with Iodine adsorption value from 36 to 160 mg/g from 0 to 60 phr with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr,
(B) The sub-tread buried under the toroidal road touching part "cap", called "buried sub-tread" comprising rubber composition Natural rubber from 0 to 100 phr and/or Solution/Emulsion SBR with or without functionalisation 0-100 phr and/or Poly butadiene with or without functionalisation 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or without coupling agent and/or carbon black with Iodine adsorption value from 36-160 mg/g from 0 to 60 phr with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr,
(C) the side walls rubber composition can be the same compound which is touching the ground called 'cap' or the rubber composition which is buried under the ground touching part 'cap' called 'buried sub-tread' or any other rubber composition with Natural rubber from 0 to 100 phr and/or Solution/Emulsion SBR with or without functionalisation 0-100 phr and/or Poly butadiene with or without functionalisation 0-60 phr and/or silica, precipitated and/or dispersible 0-80 phr with or

without coupling agent and/or carbon black with Iodine adsorption value from 36-160 mg/g from 0 to 60 phr with a single grade and/or a combination of black grades and/or plasticizer from 0 to 20 phr.
2, A Pneumatic Bias motor cycle and scooter tyre as per claim 1 with buried sub tread having tread
compound with toroidal shape surface as a whole, touching the road "cap", the compound composition
having loss tangent (Tan 5) and storage modulus (G') measured in Dynamic Mechanical Analyzer in
shear mode at frequency 1 Hz and strain of 2.5%;
at30°C Tan6> 0.210
at60°C Tan5< 0.200
at30°C Storage modulus G' > 2.00 MPa
at60°C Storage modulus G' > 1.50 MPa.
3, A Pneumatic Bias motor cycle and scooter tyre as per claim 1 with buried sub tread having tread
compound with toroidal shape surface as a whole touching the road called "cap" and the sub-tread
buried in the "cap" having loss tangent (Tan 5) and storage modulus (G') measured in Dynamic
Mechanical Analyzer in shear mode at frequency 1Hz and strain of 2.5%;
at60°C Tan 5 < 0.180
at30°C Storage modulus G' > 1.20 MPa
at60°C Storage modulus G' > 1.00 MPa.
4, The tyre of claim 1,2 and 3 wherein said tyre's outer tread surface is configured with patterns of rib
and/or lug and/or blocks and/or combination of the any of the above mentioned patterns.