Pneumatic tire

a technology of pneumatic tires and side portions, which is applied in the field of pneumatic tires, can solve the problems of insufficient long wear resistance period of tire products, and insufficient durability of side portions, etc., and achieves excellent wear resistance performance, low rolling resistance, and high durability of side portions. appearance

Active Publication Date: 2012-08-02
BRIDGESTONE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0006]In view of the problems described above, an object of the present invention is to propose detailed tire configurations for providing a tire having excellent wear resistance performance, low rolling resistance and high durability of side portion's appearance.Means for Solving the Problem
[0007]The inventor of the present invention has discovered that performances of a tire can be improved as desired by meticulously regulating the tire shape and that, in a case of shape designing, in particular, it is effective to individually regulate respective shapes of reinforcing structures as a framework of the tire, as well as the shape of the outer surface of the tire, because the shapes of reinforcing structures have significant influences on tire performances. Specifically, the inventor has discovered that suppressing shear deformation of a tire in a section in the tire width direction, in particular, shear deformation in a tread on the outer side in the width direction thereof results in simultaneous improvement of decrease in rolling resistance generated as a result of energy loss caused by this deformation and reduction of wear often generated by shearing force and slip also caused by the deformation.
[0008]The inventor has also discovered that it is possible to improve durability of side portion's appearance which is often seen in a tire having a flat belt by specifying a turn-up height of a carcass ply without decreasing the above-mentioned wear resistance performance and rolling resistance performance, thereby completing the present invention.
[0009]In addition, the inventor has discovered that it is possible to further improve durability of side portion's appearance by providing a carcass ply reinforcing layer and by specifying a height of a bead filler.

Problems solved by technology

First, it is known that a relatively large proportion of rolling resistance of a tire is generated in rubber of a tread portion.
However, it is also known that other performances of the tire such as wear resistance performance are sacrificed in this method.
However, in this case there arises a problem that a sufficiently long wear-resisting period cannot be ensured in the product life of the tire.
However, durability of side portion's appearance is not sufficient and more specified tire designing is still needed in order to achieve other performances, in particular, excellent wear resistance as well.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0031]FIG. 2 shows a widthwise section of a pneumatic tire (hereinafter, referred to as a tire) according to the first embodiment of the present invention. A tire 6 of the present invention comprises a carcass 2 as a framework consisting of at least one carcass ply (one carcass ply in this figure) troidally extending between bead portions embedded with a pair of bead cores 1 and turned around the bead cores 1 from an inner side to an outer side in the tire width direction, a belt comprising at least one inclined belt layer (two inclined belt layers 3a, 3b in this figure) and one circumferential belt layer 4 disposed on a radially outer side of a crown portion of the carcass 2 and a tread 5 disposed on the radially outer side of the belt. The two inclined belt layers 3a, 3b are formed by coating a number of cords extending in a direction inclined with respect to a tire equatorial plane CL with rubber, and the circumferential belt layer 4 is formed by coating a number of cords extendi...

second embodiment

[0060]FIG. 8 shows a widthwise section of a pneumatic tire according to the second embodiment of the present invention. As shown in FIG. 8, a carcass ply reinforcing layer 8 is disposed on a widthwise outer side of the carcass 2 at the maximum width position Wmax of the tire to cover the maximum width position Wmax of the tire. The ratio CRFw / CSH is in a range between 0.2 and 0.6, where CRFw is a width of the carcass ply reinforcing layer 8 and CSH is a distance from a radially outermost side of the carcass 2 to the line drawn in parallel with the tire rotation axis at the bead toe 10 and an reinforcing element embedded in the carcass ply reinforcing layer 8 is inclined at an angle of 30° to 90° with respect to the tire equatorial plane CL.

[0061]Although the carcass ply reinforcing layer 8 is disposed on the widthwise outer side of the turn-up portion 2o of the carcass ply in FIG. 8, the carcass ply reinforcing layer 8 may be disposed between the turn-up portion 2o and the body port...

third embodiment

[0069]FIG. 9 shows a widthwise section of a pneumatic tire according to the third embodiment of the present invention. As shown in FIG. 9, the ratio BFh / CSH is in a range between 0.04 and 0.40, where BFh is the height of a bead filler 9 and CSH is a distance from a radially outermost side of the carcass 2 to the line drawn in parallel with the tire rotation axis at the bead toe 10. The height BFh of the bead filler 9 means a distance from a radially outermost side of the bead filler 9 to the line drawn in parallel with the tire rotation axis at the bead toe 10.

[0070]The turn-up portion 2o of the carcass ply is overlapped with the body portion 2h of the carcass ply at the maximum width position Wmax of the tire on which bending of the side portion is concentrated to reinforce this position and the bead filler 9 is set small so that the bending deformation is applied to the whole side portion under load and therefore, the bending deformation can be prevented from being concentrated on...

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Abstract

There is provided a pneumatic tire having excellent uneven wear resistance performance, low rolling resistance and durability of side portion's appearance. The pneumatic tire comprises a carcass as a framework consisting of at least one carcass ply troidally extending between bead portions embedded with a pair of bead cores and turned around the bead cores from an inner side to an outer side in a tire width direction, a belt comprising at least one inclined belt layer and a tread successively disposed on a radially outer side of a crown portion of the carcass, wherein a ratio BD / BW is in a range between 0.01 and 0.04 in a section of the tire in the width direction in a state where the tire is mounted on an application rim, where BD is radius difference between radius at a central portion and radius at an end portion in the tire width direction of the outermost layer of the inclined belt layer and BW is a width of the outermost layer and CSEh is larger than SWh, where CSEh is a shortest distance from an end of a turn-up portion of the at least one carcass ply to a line drawn in parallel with a tire rotation axis at a bead toe and SWh is a shortest distance between a line drawn in parallel with the tire rotation axis at a maximum width position of the tire and the line drawn in parallel with the tire rotation axis at the bead toe.

Description

TECHNICAL FIELD[0001]The present invention relates to a pneumatic tire having excellent uneven wear resistance performance and low rolling resistance.RELATED ART[0002]In recent years, there has been actively pursued development of products having relatively little undesirable impact on the environment. This trend is due to the environmental problems including global warming and a tire is not an exception in development of such environmentally friendly products. Regarding tires, it is important to ensure performances thereof contributing to reducing fuel consumption of an automobile in order to address these environmental problems. Reducing rolling resistance of a tire has been proposed as one way of achieving such a task and various technologies have been developed in this regard.[0003]Some of the conventional methods of decreasing rolling resistance are as follows.[0004]First, it is known that a relatively large proportion of rolling resistance of a tire is generated in rubber of a...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B60C9/18
CPCB60C3/04B60C9/28Y10T152/10864B60C2009/283Y10T152/10765B60C15/0036B60C2015/009
Inventor KATAYAMA, SHINSAKU
Owner BRIDGESTONE CORP
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