(19)
(11)EP 3 028 876 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
06.11.2019 Bulletin 2019/45

(21)Application number: 14832817.2

(22)Date of filing:  01.07.2014
(51)Int. Cl.: 
B60C 11/04  (2006.01)
B60C 11/03  (2006.01)
(86)International application number:
PCT/JP2014/067574
(87)International publication number:
WO 2015/015988 (05.02.2015 Gazette  2015/05)

(54)

TIRE FOR MOTORBIKE

REIFEN FÜR EIN MOTORRAD

PNEU POUR MOTOCYCLETTE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 29.07.2013 JP 2013157004

(43)Date of publication of application:
08.06.2016 Bulletin 2016/23

(73)Proprietor: Sumitomo Rubber Industries, Ltd.
Kobe-shi, Hyogo 651-0072 (JP)

(72)Inventor:
  • TAKENAKA Kouji
    Kobe-shi Hyogo 651-0072 (JP)

(74)Representative: Manitz Finsterwald Patent- und Rechtsanwaltspartnerschaft mbB 
Martin-Greif-Strasse 1
80336 München
80336 München (DE)


(56)References cited: : 
EP-A1- 2 181 864
WO-A1-2013/046266
JP-A- 2009 029 176
JP-A- 2013 116 709
WO-A1-2011/080566
JP-A- H02 133 206
JP-A- 2010 111 163
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical field



    [0001] The present invention relates to a motorbike tire having good balance to improve the turning performance and dry grip performance.

    BACKGROUND



    [0002] In general, in order to improve the turning performance of the motorbike tire is required to improve roll agility of transient characteristics during cornering.

    [0003] The roll agility is a turning performance in a turning early period where a motorbike is slightly tilted from a straight running state and in a turning middle period where the motorbike is more tilted from the turning early period. The roll agility is represented by a length of time from the straight running period to the turning early period or from the turning early period to the turning middle period of the motorbike depending on a rider's steering. As this length of time is shorter, the roll agility is better. In order to improve the roll agility, it is necessary that deformation of the tire is promoted in the turning early period and the turning middle period.

    [0004] On the other hand, the transient characteristic is a turning performance in the turning middle period or later. The transient characteristic is represented by a length of time of the motorbike until further roll from the turning middle period depending on the rider's steering. As this length of time is longer, the turning stability is higher and the transient characteristic is better. To improve the transient characteristic, it is necessary that the deformation of the tire is suppressed in the turning middle period or later. Following is a technology related to the present invention.

    CITATION


    Patent literature



    [0005] Patent Document 1: Japanese published unexamined application 2001-39120.
    WO 2011/080566 A1 discloses a motorbike tire in accordance with the preamble of claim 1.
    EP 2 181 864 A1 discloses a motorbike tire whose tread portion is provided with a plurality of inclined axial grooves that overlap substantially with one another in the axial direction of the tire.

    Summary of the invention


    Problems that the Invention is to solve



    [0006] A motorbike tire according to the present invention has a tread portion, wherein the tread portion includes a right region with respect to the tire equator and a left region with respect to the ti re equator, each of the right region and the left region is provided with a plurality of first inclined grooves disposed on the tire equator side and spaced in the circumferential direction of the tire, and a plurality of second inclined grooves disposed nearer the tread end side than the first inclined groove and spaced in the circumferential direction of the tire. The first inclined grooves comprise right first inclined grooves provided in the right region and left first inclined grooves provided in the left region. The second inclined grooves comprise right second inclined grooves provided in the right region and left second inclined grooves provided in the left region. The first inclined grooves are provided in a straight contact region configured to come into contact with a flat surface when the tire is assembled in a normal rim and is filled with normal internal pressure, loaded with a normal load and at a camber angle of 0 degrees. In the right region and the left region, an axially inner end of each second inclined groove is provided within 2% of a tread developed half width of an end edge of the straight contact region, and an axially outer end of each second inclined groove is disposed from 20% to 30% of the tread developed half width closer to the tread end than the axially inner end of the second inclined grooves. No grooves other than the second inclined grooves are provided in a second inclined groove forming region defined by circumferentially projecting the second inclined grooves, or a region length in the developed width direction of a portion of any groove apart from the second inclined grooves that is provided in the second inclined groove forming region is not more than 25% of a developed width of the second inclined groove forming region.

    [0007] According to one aspect, the tread portion has a designated rotational direction. Each of the first inclined grooves extends axially outwardly from an axially inner end toward the opposite direction of the rotational direction, and each of the second inclined grooves extends from the axially inner end to the axially outer end in the tire axial direction.

    [0008] In the motorbike tire according to claim 1 or 2, in the right region and the left region, an axially inner end of each first inclined groove may be provided on the tread end side without intersecting with the tire equator.

    [0009] In the motorbike tire in accordance with the present invention, it is preferable that each first inclined groove has an angle of from 5 to 20 degrees with respect to the tire circumferential direction and each second inclined groove has an angle of from 10 to 30 degrees with respect to the circumferential direction of the tire.

    [0010] In the motorbike tire in accordance with the present invention, a land ratio of the straight contact region of the tread portion is preferably in a range of from 0.90 to 0.95, and a land ratio of the second inclined groove forming region of the tread portion is preferably in a range of from 0.91 to 0.97.

    [0011] In the motorbike tire according to any one of claims 1 to 5, the first inclined grooves and the second inclined grooves in each of the right region and the left region may be arranged alternately in the tire circumferential direction.

    [0012] In the motorbike tire in accordance with the present invention, the right first inclined grooves and the left first inclined grooves are preferably arranged alternately in the tire circumferential direction.

    [0013] In the motorbike tire in accordance with the present invention, each of the right region and the left region may comprise third inclined grooves that are spaced in the tire circumferential direction, and an axially inner end of each third inclined groove is preferably positioned axially outwards of the axially inner ends of the second inclined grooves.

    [0014] In the motorbike tire in accordance with the present invention it is preferable that each third inclined groove has the same direction of inclination as the second inclined grooves and has an angle with respect to the tire circumferential direction larger than an angle of the second inclined groove with respect to the tire circumferential direction.

    [0015] in the motorbike tire in accordance with the present invention preferably, in each of the right region and the left region, fourth inclined grooves are spaced in the tire circumferential direction, an axially inner end of each fourth inclined groove is positioned axially outwards of the axially inner end of the third inclined groove.

    [0016] In the motorbike tire in accordance with the present invention, it is preferable that each fourth inclined groove has the same direction of inclination as the third inclined grooves and has an angle with respect to the tire circumferential direction larger than an angle of the third inclined groove.

    Effect of the invention



    [0017] In the motorbike tire of the present invention, the first inclined groove is provided in the straight contact region. This makes smaller the pattern rigidity of the straight ground area, and the deformation of the tire is promoted where moving from the straight running to the turning. For this reason, the roll agility is improved.

    [0018] The axially inner end of the second inclined groove is provided in the vicinity of the edge of the straight contact region. Thus, the pattern rigidity in the edge vicinity of the straight contact region decreases and the deformation of the tire is promoted in the turning early period and the turning middle period. For this reason, the roll agility is further improved.

    [0019] The axially outer end of the second inclined groove is disposed from 20% to 30% of the tread developed half width nearer the tread end side than the axially inner end of the second inclined groove. Thus, the pattern rigidity of the axially outside of the tread portion is maintained high, and the deformation of the tire is suppressed in the turning middle period or later. For this reason, the transient characteristic and the dry grip performance are improved.

    [0020] No groove other than the second inclined groove is provided in the second inclined groove forming region, or a region length in the developed width direction of the other groove is defined as not more than 25% of the developed width of the second inclined groove forming region. Thus, the rigidity of the second inclined groove forming region is secured, and the deformation of the tire is further suppressed in the turning middle period or later. For this reason, the transient characteristic and the dry grip performance are even more improved.

    [0021] Therefore, in the motorbike tire of the present invention, the turning performance and the dry grip performance are improved in good balance.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0022] 

    FIG. 1 is a development view of a tread portion of a motorbike tire showing an embodiment of the present invention.

    FIG. 2 is a cross-sectional view of the motorbike tire corresponding to the X-X cross-section of FIG. 1.

    FIG. 3 is a development view of the tread portion of the motorbike tire showing an embodiment of the present invention.

    FIG. 4 is a development view of the tread portion showing another embodiment of the present invention.

    FIG. 5 is a development view of the tread portion of yet another embodiment of the present invention.

    FIG. 6 is a development view of the tread portion showing an embodiment of a comparative example.


    EMBODIMENTS OF THE INVENTION



    [0023] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

    [0024] FIG. 1 is a development view of a tread portion 2 of a motorbike tire (hereinafter, simply referred to as "tire") of the present embodiment. FIG. 2 is an X-X line sectional view of Fig. 1. As used herein, particularly stated otherwise regarding such a ground state, dimensions of each part of the tire are the value specified in the normal state of the tire mounted on a normal rim with the normal inner pressure and unloaded.

    [0025] The "normal rim" means a rim determined for each tire by a normal including one on which the tire is based, and the normal rim is the normal rim in the case of JATMA, a "Design Rim" in the case of TRA, and a "Measuring Rim" in the case of ETRTO.

    [0026] The "normal internal pressure" means an air pressure determined for each tire by the normal. The "normal internal pressure" is a maximum air pressure in JATMA, a maximum value described in a table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and "INFLATION PRESSURE" in the case of ETRTO.

    [0027] The tire of the present embodiment comprises an asymmetric tread pattern having a designated rotational direction R of the tire. The rotation direction R of the tire is shown in a sidewall portions (shown in FIG. 2), for example, in characters or the like.

    [0028] As shown in FIG. 2, in the tire, in order to obtain a sufficient ground contact area even at the time of turning when the camber angle is deep, an outer surface 2a between tread ends 2t and 2t of the tread portion 2 extends curved in a circular arc convexed toward the outside. A tread width TW, which is an axial length between the tread ends 2t and 2t, is the greatest width of the tire. A deployment length of the outer surface 2a between the tread ends 2t and 2t is a tread width TW. A developed length of the outer surface 2a between the tread end 2t and the tire equator C is a tread developed half width CW.

    [0029] The tire comprises a carcass 6 extending from the tread portion 2 through a sidewall portion 3 to a bead core 5 of a bead portion 4, and a tread reinforcing layer 7 disposed radially outer side and inside of the carcass 6 in the tread portion 2.

    [0030] The carcass 6 is formed of a single carcass ply 6A, for example. The carcass ply 6A includes a main body 6a extending from a tread portion 2 through the sidewall portion 3 to the bead cores 5 embedded in the bead portion 4, and a turned-up portion 6b which is continued to the main body portion 6a and turned up around the bead core 5.

    [0031] The carcass ply 6A has a carcass cord inclined at an angle of preferably from 75 to 90 degrees, for example, more preferably from 80 to 90 degrees with respect to the tire equator C. For the carcass cord, an organic fiber cord, e.g. nylon, polyester, rayon and the like is preferably used. Incidentally, between the main portion 6a and turned-up portion 6b of the carcass ply 6A, a bead apex 8 made of hard rubber is disposed.

    [0032] The tread reinforcing layer 7 is formed of at least a single belt cord arranged to be inclined at a small angle of from 5 to 40 degrees with respect to the tire equator C, in the present embodiment two belt plies, that is to say radially inner and outer plies, 7A and 7B of which belt cords are intersected with each other. In addition, for the belt cord, steel cords, aramid or rayon or the like is preferably employed, for example.

    [0033] As shown in FIG. 1, the tread portion 2 of the tire of the present embodiment includes a right region RE disposed on the right side of the tire equator C, and a left region LE disposed on the of the tire equator C.

    [0034] The tread portion 2 of the tire comprises a straight contact region ES. The straight contact region ES is a region where the tire under the normal state with the normal load contacts with a plane surface at the camber angle of 0 degrees. A developed width Sw between the end edges Se and Se of the straight contact region ES is in a range of from 40% to 60% of the tread developed half width CW, for example. The axial center of the straight contact region is provided on the tire equator C.

    [0035] In this embodiment, each of the right region RE and the left region LE of the tread portion 2 comprises a first inclined groove 11, a second inclined groove 12, a third inclined groove 13, and a fourth inclined groove 14 which are spaced in the circumferential direction of the tire from the tire equator C toward the tread end 2t. Thus, each of the right region RE and the left region LE comprises a second inclined groove forming region E2 (shown in FIG. 3) where the second inclined groove 12 is projected in the tire circumferential direction, and a third inclined groove forming region E3 where the third inclined groove 13 is projected in the circumferential direction.

    [0036] The first inclined groove 11 is provided in the straight contact region ES. This makes smaller the pattern rigidity of the straight contact region ES, and the deformation of the tire is promoted when shifting from the straight running to the turning. For this reason, the roll agility in the turning early period can be improved.

    [0037] Each of the first inclined grooves 11 extends from the axially inner end 11i toward the opposite direction of the rotation direction R to the axially outer end 11e. As a result, the lateral rigidity of the axially outside of the first inclined groove 11 decreases toward the backward direction of the rotation. Therefore, the deformation of the tire when shifting from the straight running to the turning is further promoted. Therefore, the roll agility is further improved.

    [0038] In order to effectively exhibit the effect described above, the first inclined groove 11 preferably has an angle θ1 of from 5 to 20 degrees with respect to the tire circumferential direction. That is, when the angle θ1 of the first inclined groove 11 is less than 5 degrees. the lateral rigidity of the axial outward of the first inclined groove 11 can not be effectively reduced toward the backward direction of the rotation, and there is a possibility that the roll agility of the turning early period is lowered. Also, when the angle θ1 of the first inclined groove 11 exceeds 20 degrees. there may not be effectively reduced the pattern rigidity of the straight contact region ES. In this specification, the angle θ1 of the first inclined groove 11 is defined by a vi rtual straight line connecting the axially outer end 11e and the axially inner end 11i of the first inclined groove 11 (the same applies to another inclined groove).

    [0039] The axially inner end 11i of the first inclined groove 11 is provided on the tread end 2t side without intersecting the tire equator C in this embodiment. Thus, the pattern rigidity of the tread portion 2 on the tire equator C is secured high, and the dry grip performance during the straight running can be secured high. when a length L1 in the developed width direction between the axially inner end 11i of the first inclined groove 11 and the tire equator C is large, it is not possible to reduce the pattern rigidity of the entire straight contact region ES, and there is a possibility that the roll agility is deteriorated. Therefore, the length L1 in the developed width direction between the axially inner end 11i of the first inclined groove 11 and the tire equator C is preferably from 1.0% to 3.0% of the tread developed half width CW.

    [0040] The axially outer end 11e of the inclined groove 11 of the present embodiment is provided on the axially outer side than the end edge Se of the straight contact region ES. Thus, the pattern rigidity of the vicinity of the end edge of the straight contact region ES further decreases, and the deformation of the tire between the turning early period and the turning middle period is further promoted. when the outer end 11e of the first inclined groove 11 is provided axially outer side than the end edge Se of the straight contact region ES, there is a possibility that the deformation of the tire is promoted also in the turning middle period or later. Therefore, the length L2 in the developed width direction between the outer end 11e of the first inclined groove 11 and the end edge Se of the straight contact region ES is preferably in a range of from 2% to 10% of the tread developed half width CW.

    [0041] A land ratio R1 of the straight contact region ES is preferably in a range of from 0.90 to 0.95. As a result, the dry grip performance in the straight running period and the roll agility in the turning early period are improved in good balance. when the land ratio R1 of the straight contact region ES is less than 0.90, the pattern rigidity of the straight contact region ES decreases, and the dry grip performance, especially the dry grip performance in the straight running period, is likely to be worse. when the land ratio R1 of the straight contact region ES is more than 0.95, the pattern rigidity of the straight contact region ES increases, and the roll agility in the turning early period is likely to be worse. The land ratio R1 of the straight contact region ES is a ratio (Ma / Mb) between a total surface area Ma of a tread of the straight contact region ES and a virtual surface area Mb of a tread of the straight contact region ES obtained by filling the first inclined groove 11 or the second inclined groove 12.

    [0042] A right first inclined groove 11A provided in the right region RE and a left first inclined groove 11B provided in the left region LE are arranged alternately in the tire circumferential direction in this embodiment. As a result, the pattern rigidity of the straight contact region ES is ensured in good balanced on both sides of the tire equator C, further the turning performance is improved.

    [0043] The first inclined groove 11 of this embodiment includes a tapering section 11a of which a groove width W1 is gradually reduced toward the one side in the tire circumferential direction (a bottom side in FIG. 1) in not less than 70% of the circumferential length L3 of the first inclined groove 11. The first inclined groove 11 is possible to suppress the excessive decrease of the pattern rigidity of the straight contact region ES and to ensure the dry grip performance.

    [0044] In order to improve the roll agility and the dry grip performance in good balance, the groove width W1 of the first inclined groove 11 (a developed width along the longitudinal direction) is preferably in a range of about from 2.0 to 7.0 mm. The groove depth D1 of the first inclined groove 11 (shown in FIG. 2) is preferably in a range of about from 2.0 to 6.0 mm.

    [0045] The axially inner end 12i of the second inclined groove 12 is provided in the region ranging 2% of the tread developed half width CW with respect to the end edge Se of the straight contact region ES. Thus, a pattern rigidity of a vicinity of the end edge Se of the straight contact region ES decreases, and the deformation of the ti re is further accelerated in the turning early period and the turning middle period. For this reason, the roll agility is further improved. when the axially inner end 12i of the second inclined groove 12 is provided in the axial inside of the end edge Se of the straight contact region ES beyond 2% of the tread developed half width Cw, the dry grip performance in the straight running period is greatly reduced. when the axially inner end 12i of the second inclined groove 12 is provided in the axial outside of the end edge Se of the straight contact region ES beyond 2% of the tread developed half width CW, it is not possible to reduce the pattern rigidity of the vicinity of the end edge Se of the straight contact region ES. Therefore, the deformation of the tire is suppressed between the turning early period and the turning middle period.

    [0046] The axially outer end 12e of the second inclined groove 12 is disposed from 20% to 30% of the tread developed half width CW nearer the tread end 2t side than the axially inner end 12i of the second inclined groove 12. Thus, the pattern rigidity of the axial outside of the tread portion 2 is kept high, and the deformation of the tire is suppressed in the turning middle period or later. For this reason, the transient characteristic and the dry grip performance are improved.

    [0047] when the outer end 12e of the second inclined groove is provided at a position less than 20% of the tread developed half width CW spaced from the axially inner end 12i , it is not possible to reduce the pattern rigidity of the tread portion 2 which grounds in the turning middle period. For this reason, the roll agility in the turning middle period deteriorates.When the outer end 12e of the second inclined groove is provided at a position more than 30% of the tread developed half width CW spaced from the axially inner end 12i, the pattern rigidity of the axially outside of the tread portion 2 is lowered, and the deformation of the tire is promoted also between the turning middle period and the turning terminal period. For this reason, the transient characteristic and the dry grip performance are deteriorated.

    [0048] As shown in FIG. 3, the second inclined groove forming region E2 comprises grooves other than the second inclined groove 12. In the second inclined groove forming region E2 in this embodiment, the first inclined groove 11 and the third inclined groove 13 are disposed. Region lengths (L4 + L5) in the developed width direction of the grooves 11 and 13 other than the second inclined groove 12 is not more than 25% of the developed width AW of the second inclined groove forming region E2. Thus, the rigidity of the second inclined groove forming region E2 is secured, and the deformation of the tire is further suppressed in the turning middle period or later.

    [0049] From the viewpoints of reducing the rigidity of the axial inside of the second inclined groove forming region E2 and of smoothing the deformation of the tire between the turning early period and the turning middle period, it is preferable that the region length L4 in the developed width direction of the first inclined groove 11 disposed in the second inclined groove forming are E2 is not more than 15% of the developed width AW of the second inclined groove forming region E2. The region length L5 in the developed width direction of the third inclined groove 13 disposed in the axially outside of the second inclined groove forming region E2 is preferably not more than 5% of the developed width AW of the second inclined groove forming region E2 in order to reliably suppress the deformation of the tire.

    [0050] In view of even improving in the transient characteristic and the dry grip performance, the second inclined groove forming region E2 may have an aspect of not comprising other than the second inclined groove 12.

    [0051] A land ratio R2 of the second inclined groove forming region E2 is preferably in a range of from 0.91 to 0.97. That is, when the land ratio R2 of the second inclined groove forming region E2 is less than 0.91, the dry grip performance may be lowered in the turning middle period. when the land ratio R2 of the second inclined groove forming region E2 is greater than 0.97, there is a possibility that the deformation of the tire is not promoted between the turning early period and the turning middle period. The land ratio R2 is a ratio (Mc/Md) between a total surface area Mc of the tread of the second inclined groove forming region E2 and a virtual surface area Md of a virtual tread surface of the second inclined groove forming region obtained by filling through the first inclined groove 11 to third inclined groove 13.

    [0052] The land ratio R2 of the second inclined groove forming region E2 is preferably greater than the land ratio R1 of the straight contact region ES. As a result, since the pattern rigidity of the second inclined groove forming region E2 is ensured larger than the pattern rigidity of the straight contact region ES, the deformation of the tire in the turning middle period or later is reliably prevented. Therefore, the roll agility in the turning early period and the transient characteristic in the turning middle period are improved in good balance.

    [0053] The second inclined groove 12 of the present embodiment extends from the axially inner end 12i to the axially outer end 12e in the direction of rotation R. Thus, the lateral rigidity of axially outer side of the second inclined groove 12 can be secured largely in the backward direction of the rotation. Therefore, since the deformation of the tire is suppressed in the turning middle period or later, the transient characteristic are even more improved.

    [0054] In order to effectively exhibit the effects described above, the second inclined groove 12 is preferable to have an angle θ2 of from 10 to 30 degrees with respect to the tire circumferential direction. That is, when the angle θ2 of the second inclined groove 12 exceeds 30 degrees, the tire circumferential length L6 of the second inclined groove 12 is excessively small. For this reason, the pattern rigidity of the second inclined groove forming region E2 is excessively large, and the roll agility in the turning middle period is likely to be worse. when the angle θ2 of the second inclined groove 12 is less than 10 degrees, the tire circumferential length L6 of the second inclined groove 12 is excessively large, and the pattern rigidity of the second inclined groove forming region E2 decreases, and the transient characteristic in the turning middle period or later may decrease.

    [0055] The angleθ2 of the second inclined groove 12 is preferably larger than an angleθ1 (shown in FIG.1) of the first inclined groove 11. Thus, in the time of turning, the lateral rigidity of the second inclined groove forming region E2, on which an axial road larger than the straight contact region ES acts, is improved. For this reason, the turning performance is further improved. From this standpoint, the angle θ2 of the second inclined groove 12 is preferably from 5 to 15 degrees larger than the angle θ1 of the first inclined groove 11.

    [0056] In each of the right region RE and the left region LE, the first inclined groove 11 and the second inclined groove 12 are preferably provided alternately in the tire circumferential direction. As a result, in each of the right region RE and the left region LE, the pattern rigidity can be secured in good balance. For this reason, the turning performance and the dry grip performance can improved in better balance.

    [0057] The second inclined groove 12 of the present embodiment includes a tapering section 12a where a groove width w2 gradually reduces toward the axial outside in more than 70% of the second tire circumferential length L6 of the inclined grooves 12. Such a second inclined groove 12 increases the pattern rigidity of the tire axial outside of the second inclined groove forming region E2 and improves the dry grip performance and the transient characteristic.

    [0058] In order to improve the roll agility and the dry grip performance in good balance, the groove width w2 of the second inclined groove 12 is preferably about from 1.5 to 6.5 mm. A groove depth D2 (shown in FIG. 2) of the second inclined groove 12 is preferably about from 70% to 90% of the groove depth D1 of the first inclined groove 11.

    [0059] As shown in FIG. 1, an axially inner end 13i of the third inclined groove 13 is provided on the axially outer side than the axially inner end 12i of the second inclined groove 12. Thus, the rigidity of the second inclined groove forming region E2 is secured, and the deformation of the tire is suppressed in the turning middle period or later. when a length L7 in the developed width direction, which is a length between the inner end 13i of the third inclined groove 13 and the inner end 12i of the second inclined grooves 12, is excessively large, a rigidity difference near the axially outer end 12e of the second inclined groove 12 increases, the tire may not possibly turn smoothly. Therefore, the length L7 in the developed width direction is preferably in a range of from 85% to 100% of the developed width AW (shown in FIG. 3) of the second inclined groove forming region E2.

    [0060] The third inclined groove 13 is inclined in the same di recti on as the second inclined groove 12. That is, the third inclined groove 13 extends from the axially inner end 13i of the third inclined groove 13 to the axially outer end 13e in the rotation direction R. Thus, the lateral rigidity of the land portion in the axially outer side than the third inclined groove 13 increases even larger toward the backward direction of the rotation. Therefore, the deformation of the tire is suppressed in from the turning middle period to the turning later period.

    [0061] The third inclined groove 13 preferably has an angle θ3 with respect to the tire circumferential direction larger than the second inclined groove 12. As a result, the lateral rigidity of a third inclined groove forming region E3, on which a lateral force larger than the second inclined groove forming region E2 acts, is largely secured. Therefore, the turning performance is further improved. when the angle θ3 of the third inclined groove 13 is excessively larger than the angle θ2 of the second inclined groove 12, the rigidity difference between the second inclined groove forming region E2 and the third inclined groove forming region E3 increases, and the tire may not possibly turn smoothly. From this standpoint, the angle θ3 of the third inclined groove 13 is preferably from 2 to 15 degrees greater than the angle θ2 of the second inclined groove 12. From the same point of view, the angle θ3 of the third inclined groove 13 is preferably in a range of from 20 to 40 degrees.

    [0062] Although not particularly limited, a developed width BW of the third inclined groove forming region E3 is preferably in a range of from 15% to 25% of the tread developed half width CW.

    [0063] An axially inner end 14i of the fourth inclined groove 14 is provided on the axially outer side than the axially inner end 13i of the third inclined groove 13. Thus, the pattern rigidity of the third inclined groove forming region E3 is secured high. A length L8 in the developed width direction between the inner end 14i of the fourth inclined groove 14 and the inner end 13i of the third inclined groove 13 is preferably in a range of from 85% to 100% of the developed width BW of the third inclined groove forming region E3.

    [0064] The fourth inclined groove 14 has an inclination in the same direction as the third inclined groove 13. That is, the fourth inclined groove 14 extends from the axially inner end 14i of the fourth inclined groove 14 to the axially outer end 14e in the rotation direction R. Thus, the lateral rigidity in the axially outer side of the fourth inclined groove 14 is ensured even greater toward the backward direction of the rotation. Thus, since the deformation of the tire is suppressed in the turning terminal period, the transient characteristic is further improved.

    [0065] The fourth inclined groove 14 has an angle θ4 with respect to the tire circumferential direction larger than the angle θ3 of the third inclined groove 13. As a result, the lateral rigidity of the land portion outward the third inclined groove forming region E3, on which a large lateral force than the third inclined groove forming region E3 acts, is largely secured. when the angle θ4 of the fourth inclined groove 14 is excessively larger than the angle θ3 of the third inclined groove 13, the rigidity difference between the third inclined groove forming region E3 and the land portion outward the third inclined groove forming region E3 may increase. For this reason, the angle θ4 of the fourth inclined groove 14 is preferably from 20 to 40 degrees larger than the angle θ3 of the third inclined groove 13. From the same point of view, the angle θ4 of the fourth inclined groove 14 is preferably in a range of from 50 to 70 degrees.

    [0066] The outer end 14e of the fourth inclined groove 14 terminates in the tread portion 2 without reaching the tread end 2t. As a result, the transient characteristic in the time of maximum turning is further improved.

    [0067] To improve the roll agility and the dry grip performance in good balance, the third groove width w3 of the third inclined grooves 13 and the groove width w4 of the fourth inclined groove 14 are preferably in a range of from 1.0 to 6.0 mm. A groove depth D3 (shown in FIG. 2) of the third inclined groove 13 and a groove depth (not shown) of the fourth inclined groove 14 are preferably in a range of from 70% to 90% of the groove depth D1 of the first inclined groove 11.

    [0068] Above, although embodiments of the invention have been described in detail, the invention is not intended to be limited to the specific embodiments described above are implemented by changing the various aspects.

    Example



    [0069] In order to confirm the effects of the present invention, motorbike tires having a basic pattern of FIG. 1 were tested based on the specifications shown in Table 1. The main common specifications and testing methods of each tire were as follows.
    Tread width Twa: 122 mm
    Tread developed half width Cw: 83 mm
    Developed width Sw of straight contact region: 41 mm
    Groove depth D1 of first inclined groove: 4.1 mm
    Groove depth D2 of second inclined groove: 3.7 mm
    Groove depth D3 of third inclined groove: 3.5 mm
    Angle θ3 of third inclined groove: 35 degrees
    Groove depth D4 of fourth inclined groove: 3.3 mm
    Angle θ4 of fourth inclined groove: 60 degrees
    Pitch L (shown in FIG. 1) of first inclined groove: 188 mm

    <Turning performance and Dry grip performance>



    [0070] Each of the test tires were attached to the all-wheel s of a motorbike of 1000 cc displacement under the following conditions. Then, a test rider ran the motorbike on a test course of dry asphalt road surface and evaluated turning performance by roll agility and transient characteristic and driving characteristics regarding dry grip in a sensory test. The results are displayed in five-point method with the conventional example as 4.0. The numerical value is larger, the better the turning performance and dry grip performance.

    (Front tire)



    [0071] Size: 120/70ZR17
    Rim: MT3.50 x 17
    Internal pressure: 250 kPa

    (Rear tire)



    [0072] Size: 190/55ZR17
    Rim: MT6.00 x 17
    Internal pressure: 290kPa

    [0073] The test results and the like are shown in Table 1.
    [Table 1]
     Con. Ex.Compar. Ex. 1Ex. 1Compar. Ex. 2Ex. 2Ex. 3Compar. Ex. 3Compar. Ex. 4Ex. 4Ex. 5Compar. Ex. 5Ex. 6
    Figure showing shape of tread portion FIG. 1 FIG. 6 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1
    Length in developed width direction between end edge and inner end of second inclined groove / CW [%] *1 10 0 0 -3 -2 2 3 0 0 0 0 0
    Length in developed width direction between outer end and inner end of second inclined groove / CW [%]*1 22 25 25 25 25 25 25 18 20 30 35 25
    Region length of another groove / developed width of second inclined groove forming region [%]*2 100 5 25 25 25 25 25 25 25 25 25 20
    Angle θ1 of first inclined groove angle [degrees] 10 - 10 10 10 10 10 10 10 10 10 10
    Angle θ2 of second inclined groove [degrees] 20 20 20 20 20 20 20 20 20 20 20 20
    Land ratio R1 of straight contact region [%] 91 100 92 90 91 92 92 92 92 92 92 92
    Land ratio R2 of second inclined groove forming region [%] 95 95 95 95 95 95 95 95 95 95 95 95
    Roll agility in turning early period [5-point method; Larger is better.] 4.0 3.5 5.0 3.5 4.0 4.0 3.5 4.0 4.0 4.5 5.0 5.0
    Roll agility in turning middle period [5-point method; Larger is better.] 4.0 4.5 5.0 4.5 4.5 4.5 4.0 3.5 4.0 4.0 3.5 4.5
    Transient characteristic [5-point method; Larger is better.] 4.0 3.0 5.0 3.5 4.0 4.0 3.5 4.0 4.0 4.0 3.5 5.0
    Dry grip performance [5-point method; Larger is better.] 4.0 5.0 5.0 4.5 4.5 4.5 5.0 5.0 5.0 5.0 4.5 5.0
    *1 End edge : End edge of straight contact region
    *1 CW: Tread developed half width
    *1 Negative notation indicates that the inner end is inside the tire axial direction than the edge.
    *2 Another groove: All the grooves other than the second inclined groove provided in the second inclined groove forming region.
    *2 Region length: A region length in the developed width direction in the second inclined groove forming region.
     Compar. Ex. 6Ex. 7Ex. 8Ex. 9Ex. 10Ex. 11Ex. 12Ex. 13Ex. 14Ex. 15Ex. 16
    Figure showing shape of tread portion FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 4 FIG. 5
    Length in developed width direction between end edge and inner end of second inclined groove / CW [%] *1 0 0 0 0 0 0 0 0 0 0 0
    Length in developed width direction between outer end and inner end of second inclined groove e / CW [%]*1 25 25 25 25 25 25 25 25 25 25 25
    Region length of another groove / developed width of second inclined groove forming region [%] *2 30 25 25 25 25 25 25 25 25 25 25
    Angle θ1 of first inclined groove angle [degrees] 10 3 5 20 22 10 10 10 10 10 10
    Angle θ2 of second inclined groove [degrees] 20 20 20 20 20 8 10 30 35 20 20
    Land ratio R1 of straight contact region [%] 92 92 92 92 92 92 92 92 92 92 92
    Land ratio R2 of second inclined groove forming region [%] 95 95 95 95 95 96 96 94 94 95 95
    Roll agility in turning early period [5-point method; Larger is better.] 4.0 4.0 4.5 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0
    Roll agility in turning middle period [5-point method; Larger is better.] 4.0 5.0 5.0 5.0 5.0 4.0 4.5 5.0 5.0 4.0 4.0
    Transient characteristic [5-point method; Larger is better.] 4.0 5.0 5.0 4.5 4.0 5.0 5.0 4.5 4.0 3.5 4.0
    Dry grip performance [5-point method; Larger is better.] 4.5 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0


    [0074] The test results, it could be confirmed that the performances were improved in good balance in the tires of Examples as compared with the tires of Comparative Examples and Conventional Examples. Moreover, it has been made the same test by changing the tire sizes, the same tendency as the test result was indicated.

    Description of the code



    [0075] 
    2
    Tread portion
    11
    First inclined groove
    12
    Second inclined groove
    ES
    Straight contact region
    Se
    End edge of straight contact region
    CW
    Tread developed half width
    2t
    Tread end



    Claims

    1. A motorbike tire having a tread portion (2), wherein
    the tread portion (2) includes a right region (RE) with respect to the tire equator (c) and a left region (LE) with respect to the tire equator (c),
    each of the right region (RE) and the left region (LE) is provided with a plurality of first inclined grooves (11) disposed on the tire equator side and spaced in the circumferential direction of the ti re, and a plurality of second inclined grooves (12) di sposed nearer to the tread end side than the first inclined grooves (11) and spaced in the circumferential direction of the tire;
    the first inclined grooves (11) comprise right first inclined grooves (11A) provided in the right region (RE) and left first inclined grooves (11B) provided in the left region (LE);
    the second inclined grooves (12) comprise right second inclined grooves provided in the right region (RE) and left second inclined grooves provided in the left region (LE);
    the first inclined grooves (11A, 11B) are provided in a straight contact region (ES) configured to come into contact with a flat surface when the tire is assembled in a normal rim, filled with normal internal pressure loaded with a normal load and at a camber angle of 0 degrees,
    characterized in that
    in the right region (RE) and the left region (LE),

    an axially inner end (12i) of each second inclined groove (12) is provided within 2% of a tread developed half width (CW) of an end edge (Se) of the straight contact region (ES), and

    an axially outer end (12e) of each second inclined groove (12) is disposed from 20% to 30% of the tread developed half width (CW) closer to the tread end (2t) than the axially inner end (12i) of the second inclined groove (12); and

    no grooves other than the second inclined grooves (12) are provided in a second inclined groove forming region (E2) defined by circumferentially projecting the second inclined grooves (12),
    or a region length (L4, L5) in the developed width direction of a portion of any groove apart from the second inclined grooves (12) that is provided in the second inclined groove forming region (E2) is not more than 25% of a developed width (AW) of the second inclined groove forming region (E2).
     
    2. The motorbike tire according to claim 1, wherein
    the tread portion (2) has a designated rotational direction (R);

    each of the first inclined grooves (11A, 11B) extends axially outwardly from an axially inner end (11i) toward the opposite direction of the rotational direction (R); and

    each of the second inclined grooves (12) extends from the axially inner end (12i) to the axially outer end (12e) in the rotational direction (R).


     
    3. The motorbike tire according to claim 1 or 2, wherein
    in the right region (RE) and the left region (LE), an axially inner end (11i) of each first inclined groove (11) is provided on the tread end side without intersecting with the tire equator (C).
     
    4. The motorbike tire according to claim 2, wherein
    each first inclined groove (11) has an angle (θ1) of from 5 to 20 degrees with respect to the tire circumferential direction, and
    each second inclined groove (12) has an angle (θ2) of from 10 to 30 degrees with respect to the ti re circumferential direction.
     
    5. The motorbike tire according to any one of claims 1 to 4, wherein
    a land ratio (R1) of the straight contact region (ES) of the tread portion (2) is in a range of from 0.90 to 0.95, and a land ratio (R2) of the second inclined groove forming region (E2) of the tread portion (2) is in a range of from 0.91 to 0.97.
     
    6. The motorbike tire according to any one of claims 1 or 5, wherein the first inclined grooves (11) and the second inclined grooves (12) in each of the right region (RE) and the left region (LE) are arranged alternately in the tire circumferential direction.
     
    7. The motorbike tire according to any one of claims 1 or 6, wherein the right first inclined grooves (11A) and the left first inclined grooves (11B) are arranged alternately in the tire circumferential direction.
     
    8. The motorbike tire according to any one of claims 1 or 7, wherein
    each of the right region (RE) and the left region (LE) comprises third inclined grooves (13) that are spaced in the tire circumferential direction; and
    an axially inner end (13i) of each third inclined groove (13) is positioned axially outwards of the axially inner ends (12i) of the second inclined grooves (12).
     
    9. The motorbike tire according to claim 8, wherein
    each third inclined groove has the same direction of inclination as the second inclined grooves (12) and has an angle (θ3) with respect to the tire circumferential direction larger than an angle (θ2) of the second inclined groove with respect to the tire circumferential direction.
     
    10. The motorbike tire according to claim 8 or 9, wherein
    in each of the right region (RE) and the left region (LE) fourth inclined grooves (14) are spaced in the tire circumferential direction,
    an axially inner end (14i) of each fourth inclined groove (14) is positioned axially outwards of the axially inner end (13i) of the third inclined groove (13).
     
    11. The motorbike tire according to claim 10, wherein each fourth inclined groove (14) has the same direction of inclination as the third inclined grooves (13), and has an angle (θ4) with respect to the tire circumferential direction larger than an angle (θ3) of the third inclined grooves (13).
     


    Ansprüche

    1. Motorradreifen mit einem Laufflächenabschnitt (2), wobei

    der Laufflächenabschnitt (2) einen rechten Bereich (RE) in Bezug auf den Reifenäquator (C) und einen linken Bereich (LE) in Bezug auf den Reifenäquator (C) umfasst,

    ein jeder von dem rechten Bereich (RE) und dem linken Bereich (LE) mit einer Vielzahl von ersten geneigten Rillen (11) versehen ist, die auf der Reifenäquatorseite angeordnet und in der Umfangsrichtung des Reifens beabstandet sind, und einer Vielzahl von zweiten geneigten Rillen (12), die näher an der Laufflächenendseite als die ersten geneigten Rillen (11) angeordnet und in der Umfangsrichtung des Reifens beabstandet sind;

    die ersten geneigten Rillen (11) rechte erste geneigte Rillen (11A) umfassen, die in dem rechten Bereich (RE) vorgesehen sind, und linke erste geneigte Rillen (11B), die in dem linken Bereich (LE) vorgesehen sind;

    die zweiten geneigten Rillen (12) rechte zweite geneigte Rillen umfassen, die in dem rechten Bereich (RE) vorgesehen sind, und linke zweite geneigte Rillen, die in dem linken Bereich (LE) vorgesehen sind;

    die ersten geneigten Rillen (11A, 11B) in einem geraden Kontaktbereich (ES) vorgesehen sind, der konfiguriert ist, um mit einer ebenen Oberfläche in Kontakt zu kommen, wenn der Reifen auf einer normalen Felge aufgezogen ist, die mit einem normalen Innendruck gefüllt ist, der mit einer normalen Last belastet ist, und mit einem Sturzwinkel von 0 Grad,

    dadurch gekennzeichnet, dass

    in dem rechten Bereich (RE) und in dem linken Bereich (LE),

    ein axial inneres Ende (12i) jeder zweiten geneigten Rille (12) innerhalb von 2% einer abgewickelten Laufflächenhalbbreite (CW) einer Endkante (Se) des geraden Kontaktbereichs (ES) vorgesehen ist, und

    ein axial äußeres Ende (12e) jeder zweiten geneigten Rille (12) von 20% bis 30% der abgewickelten Laufflächenhalbbreite (CW) näher am Laufflächenende (2t) angeordnet ist als das axial innere Ende (12i) der zweiten geneigten Rille (12); und

    keine anderen Rillen als die zweiten geneigten Rillen (12) in einem Bildungsbereich der zweiten geneigten Rillen (E2) vorgesehen sind, der durch Projizieren der zweiten geneigten Rillen (12) in Umfangsrichtung definiert ist,

    oder eine Bereichslänge (L4, L5) in der abgewickelten Breitenrichtung eines Abschnitts einer beliebigen Rille mit Ausnahme der zweiten geneigten Rillen (12), die in dem Bildungsbereich der zweiten geneigten Rillen (E2) vorgesehen sind, nicht mehr als 25% einer abgewickelten Breite (AW) des Bildungsbereichs der zweiten geneigten Rillen (E2) beträgt.


     
    2. Motorradreifen nach Anspruch 1, wobei

    der Laufflächenabschnitt (2) eine vorgegebene Drehrichtung (R) aufweist;

    eine jede der ersten geneigten Rillen (11A, 11B) sich von einem axial inneren Ende (11i) in der entgegengesetzten Richtung zu der Drehrichtung (R) axial nach außen erstreckt; und

    eine jede der zweiten geneigten Rillen (12) sich von dem axial inneren Ende (12i) zu dem axial äußeren Ende (12e) in der Drehrichtung (R) erstreckt.


     
    3. Motorradreifen nach Anspruch 1 oder 2, wobei in dem rechten Bereich (RE) und in dem linken Bereich (LE) ein axial inneres Ende (11i) jeder ersten geneigten Rille (11) auf der Laufflächenendseite vorgesehen ist, ohne den Reifenäquator (C) zu schneiden.
     
    4. Motorradreifen nach Anspruch 2, wobei

    jede erste geneigte Rille (11) einen Winkel (θ1) von 5 bis 20 Grad in Bezug auf die Reifenumfangsrichtung aufweist, und

    jede zweite geneigte Rille (12) einen Winkel (θ2) von 10 bis 30 Grad in Bezug auf die Reifenumfangsrichtung aufweist.


     
    5. Motorradreifen nach einem der Ansprüche 1 bis 4, wobei ein Landverhältnis (R1) des geraden Kontaktbereichs (ES) des Laufflächenabschnitts (2) in einem Bereich von 0,90 bis 0,95 liegt und ein Landverhältnis (R2) des Bildungsbereichs der zweiten geneigten Rillen (E2) des Laufflächenabschnitts (2) in einem Bereich von 0,91 bis 0,97 liegt.
     
    6. Motorradreifen nach einem der Ansprüche 1 oder 5, wobei die ersten geneigten Rillen (11) und die zweiten geneigten Rillen (12) in einem jeden von dem rechten Bereich (RE) und dem linken Bereich (LE) abwechselnd in der Reifenumfangsrichtung angeordnet sind.
     
    7. Motorradreifen nach einem der Ansprüche 1 oder 6, wobei die rechten ersten geneigten Rillen (11A) und die linken ersten geneigten Rillen (11B) abwechselnd in der Reifenumfangsrichtung angeordnet sind.
     
    8. Motorradreifen nach einem der Ansprüche 1 oder 7, wobei

    ein jeder von dem rechten Bereich (RE) und dem linken Bereich (LE) dritte geneigte Rillen (13) umfasst, die in der Reifenumfangsrichtung beabstandet sind; und

    ein axial inneres Ende (13i) jeder dritten geneigten Rille (13) axial außen von den axial inneren Enden (12i) der zweiten geneigten Rillen (12) positioniert ist.


     
    9. Motorradreifen nach Anspruch 8, wobei
    jede dritte geneigte Rille die gleiche Neigungsrichtung wie die zweiten geneigten Rillen (12) aufweist und einen Winkel (θ3) in Bezug auf die Reifenumfangsrichtung aufweist, der größer ist als ein Winkel (θ2) der zweiten geneigten Rille in Bezug auf die Reifenumfangsrichtung.
     
    10. Motorradreifen nach Anspruch 8 oder 9, wobei

    in einem jeden von dem rechten Bereich (RE) und dem linken Bereich (LE) vierte geneigte Rillen (14) in der Reifenumfangsrichtung beabstandet sind,

    ein axial inneres Ende (14i) jeder vierten geneigten Rille (14) axial außerhalb des axial inneren Endes (13i) der dritten geneigten Rille (13) positioniert ist.


     
    11. Motorradreifen nach Anspruch 10, wobei
    jede vierte geneigte Rille (14) die gleiche Neigungsrichtung wie die dritten geneigten Rillen (13) aufweist und einen Winkel (θ4) in Bezug auf die Reifenumfangsrichtung aufweist, der größer ist als ein Winkel (θ3) der dritten geneigten Rillen (13).
     


    Revendications

    1. Pneumatique pour motocyclette ayant une portion formant bande de roulement (2), dans lequel
    la portion formant bande de roulement (2) inclut une région de droite (RE) par rapport à l'équateur de pneumatique (C) et une région de gauche (LE) par rapport à l'équateur de pneumatique (C),
    chacune de la région de droite (RE) et de la région de gauche (LE) est dotée d'une pluralité de premières rainures inclinées (11) disposées sur le côté de l'équateur de pneumatique et espacées dans la direction circonférentielle du pneumatique, et une pluralité de secondes rainures inclinées (12) disposées plus proches du côté d'extrémité de roulement que les premières rainures inclinées (11) et espacées dans la direction circonférentielle du pneumatique ;
    les premières rainures inclinées (11) comprennent des premières rainures inclinées de droite (11A) prévues dans la région de droite (RE) et des premières rainures inclinées de gauche (11B) prévues dans la région de gauche (LE) ;
    les secondes rainures inclinées (12) comprennent des secondes rainures inclinées de droite prévues dans la région de droite (RE) et des secondes rainures inclinées de gauche prévues dans la région de gauche (LE) ;
    les premières rainures inclinées (11A, 11B) sont prévues dans une région de contact rectiligne (ES) configurée pour venir en contact avec une surface plane quand le pneumatique est assemblé sur une jante normale, rempli avec une pression interne normale, chargé avec une charge normale et avec un angle de cambrage de 0°,
    caractérisé en ce que
    dans la région de droite (RE) et dans la région de gauche (LE),
    une extrémité axialement intérieure (12i) de chaque seconde rainure inclinée (12) est prévue à l'intérieur de 2 % d'une demi-largeur développée de roulement (CW) d'une bordure terminale (Se) de la région de contact rectiligne (ES), et
    une extrémité axialement extérieure (12e) de chaque seconde rainure inclinée (12) est disposée depuis 20 % à 30 % de la demi-largeur développée de roulement (CW) plus proche de l'extrémité de roulement (2t) que l'extrémité axialement intérieure (12i) de la seconde rainure inclinée (12) ; et
    il n'est prévu aucune rainure autre que les secondes rainures inclinées (12) dans une seconde région de formation de rainure inclinée (E2) définie en projetant circonférentiellement les secondes rainures inclinées (12),
    ou une longueur de région (L4, L5) dans la direction de largeur développée d'une portion d'une quelconque rainure autre que les secondes rainures inclinées (12) qui est prévue dans la seconde région de formation de rainures inclinées (E2) n'est pas supérieure à 25 % d'une largeur développée (AW) de la seconde région de formation de rainures inclinées (E2).
     
    2. Pneumatique de motocyclette selon la revendication 1, dans lequel la portion formant bande de roulement (2) présente une direction de rotation par conception (R) ;
    chacune des premières rainures inclinées (11A, 11B) s'étend axialement vers l'extérieur depuis une extrémité axialement intérieure (11i) vers la direction opposée de la direction de rotation (R) ; et
    chacune des secondes rainures inclinées (12) s'étend depuis l'extrémité axialement intérieure (12i) vers l'extrémité axialement extérieure (12e) dans la direction de rotation (R).
     
    3. Pneumatique de motocyclette selon la revendication 1 ou 2, dans lequel
    dans la région de droite (RE) et dans la région de gauche (LE), une extrémité axialement intérieure (11i) de chaque première rainure inclinée (11) est prévue sur le côté d'extrémité de roulement sans recouper l'équateur de pneumatique (C).
     
    4. Pneumatique de motocyclette selon la revendication 2, dans lequel
    chaque première rainure inclinée (11) fait un angle (θ1) de 5 à 20° par rapport à la direction circonférentielle du pneumatique, et
    chaque seconde rainure inclinée (12) fait un angle (θ2) de 10 à 30° par rapport à la direction circonférentielle du pneumatique.
     
    5. Pneumatique de motocyclette selon l'une quelconque des revendications 1 à 4, dans lequel
    un rapport de relief (R1) de la région de contact rectiligne (ES) de la portion formant bande de roulement (2) est dans une plage de 0,90 à 0,95, et un rapport de relief (R2) de la seconde région de formation de rainure inclinée (E2) de la portion formant bande de roulement (2) est dans une plage de 0,91 à 0,97.
     
    6. Pneumatique de motocyclette selon l'une quelconque des revendications 1 ou 5,
    dans lequel les premières rainures inclinées (11) et les secondes rainures inclinées (12) dans chacune de la région de droite (RE) et de la région de gauche (LE) sont agencées alternativement dans la direction circonférentielle du pneumatique.
     
    7. Pneumatique de motocyclette selon l'une quelconque des revendications 1 ou 6,
    dans lequel les premières rainures inclinées de droite (11A) et les premières rainures inclinées de gauche (11B) sont agencées alternativement dans la direction circonférentielle du pneumatique.
     
    8. Pneumatique de motocyclette selon l'une quelconque des revendications 1 ou 7, dans lequel
    chacune de la région de droite (RE) et de la région de gauche (LE) comprend des troisièmes rainures inclinées (13) qui sont espacées dans la direction circonférentielle du pneumatique ; et
    une extrémité axialement intérieure (13i) de chaque troisième rainure inclinée (13) est positionnée axialement à l'extérieur des extrémités axialement intérieures (12i) des secondes rainures inclinées (12).
     
    9. Pneumatique de motocyclette selon la revendication 8, dans lequel
    chaque troisième rainure inclinée présente la même direction d'inclinaison que les secondes rainures inclinées (12) et fait un angle (θ3) par rapport à la direction circonférentielle du pneumatique supérieur à un angle (θ2) de la seconde rainure inclinée par rapport à la direction circonférentielle du pneumatique.
     
    10. Pneumatique de motocyclette selon la revendication 8 ou 9, dans lequel
    dans chacune de la région de droite (RE) et de la région de gauche (LE) des quatrièmes rainures inclinées (14) sont espacées dans la direction circonférentielle du pneumatique,
    une extrémité axialement intérieure (14i) de chacun quatrièmes rainures inclinées (14) est positionnée axialement à l'extérieur de l'extrémité axialement intérieure (13i) de la troisième rainure inclinée (13).
     
    11. Pneumatique de motocyclette selon la revendication 10, dans lequel chaque quatrième rainure inclinée (14) présente la même direction d'inclinaison que les troisièmes rainures inclinées (13), et fait un angle (θ4) par rapport à la direction circonférentielle du pneumatique supérieur à un angle (θ3) des troisièmes rainures inclinées (13).
     




    Drawing





















    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description