JP2008087627A - Pneumatic tire for two-wheel vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain enhancement of high speed durability, linear advancement stability and turning stability, and to perform stable traveling by enhancing linear property of ground-contact feeling and rigidity feeling when it is transferred from the linear advancement traveling state to the turning traveling state or it is transferred from the turning traveling state to the linear advancement traveling state. <P>SOLUTION: In the pneumatic tire for the two-wheel vehicle, a spiral belt layer 21 is provided between a carcass layer 9 and a tread part 13 and is formed by helically winding a ribbon-like strip material covering a belt cord 23 with a rubber in a circumferential direction C. Divided inclination belt layers 25 formed by covering a plurality of belt cords 27 inclined/extended relative to a tire circumferential direction C with a rubber are provided on a pair of shoulder side portions of the spiral belt layer 21 respectively. Further, an auxiliary spiral belt layer 29 is provided on a center side portion of the spiral belt layer 21 and is formed by helically winding a ribbon-like strip material covering a belt cord 31 with a rubber in a tire circumferential direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire for a motorcycle used for a motorcycle.

  With the recent increase in the speed of two-wheeled vehicles, high-speed durability and straight running stability are also required for pneumatic tires for two-wheeled vehicles. As a prior art, a spiral belt layer is provided between a carcass layer and a tread portion (see Patent Document 1).

  In the pneumatic tire for a motorcycle according to the first prior art, the spiral belt layer is formed by spirally winding a ribbon-shaped strip material formed by coating a belt cord with rubber in the tire circumferential direction. The tread portion can be prevented from protruding outward in the tire radial direction during high-speed running, and the bending rigidity of the entire tread portion can be reduced to increase the contact width of the tread portion during straight running. Thereby, in the pneumatic tire for a motorcycle according to the first prior art, it is possible to improve the high speed durability and the straight running stability.

  Furthermore, high turning stability has been demanded without impairing straight running stability. As a prior art (second prior art) of a pneumatic tire for a motorcycle that meets this demand, a spiral belt layer is required. Some of the pair of shoulder side portions are each provided with a split inclined belt layer formed by rubber-covering a plurality of belt cords extending inclined with respect to the tire circumferential direction (see Patent Document 2).

In the pneumatic tire for a motorcycle according to the second prior art, a split inclined belt layer is provided on a pair of shoulder side portions of the spiral belt layer. In other words, the center region of the tread portion is the spiral belt layer. Since the pair of shoulder areas of the tread is reinforced by the spiral belt layer and the split inclined belt layer, the bending rigidity of the center area of the tread is reduced, and the ground contact width of the tread during straight running is reduced. Can be increased, and the bending rigidity of the pair of shoulder regions of the tread portion can be increased to improve the grip performance (grip force) during turning. Thereby, in the pneumatic tire for a motorcycle according to the second prior art, it is possible to improve the turning stability without impairing the straight running stability.
JP-A-4-2505 Japanese Patent Laid-Open No. 2001-20609

  By the way, in the pneumatic tire for a motorcycle according to the first prior art described above, although the high-speed durability and the straight running stability can be improved, since the bending rigidity of the entire tread portion is small, There is a problem that it is difficult to improve the turning stability because the grip performance at the time becomes low.

  On the other hand, in the pneumatic tire for a motorcycle according to the second prior art, the tread portion can improve the turning stability after improving the high speed durability and the straight running stability. The center region of the tread portion is reinforced only by the spiral belt layer, and the pair of shoulder regions of the tread portion is reinforced by the spiral belt layer and the split inclined belt layer, so that a large rigidity step is formed between the center region and the shoulder region in the tread portion. Occurs. Therefore, when moving from the straight traveling state to the turning traveling state, or when moving from the turning traveling state to the straight traveling state, the linearity of the feeling of contact and the rigidity decreases, and it becomes difficult to perform stable traveling. is there. Note that even if the end portion on the tire equatorial plane side of the divided inclined belt layer is positioned within the ground contact region during straight traveling, the linearity of the ground contact feeling and the rigidity feeling cannot be sufficiently suppressed.

  Therefore, the present invention reduces the rigidity step between the center region and the shoulder region in the tread portion while improving the high-speed durability, the straight running stability, and the turning stability in order to solve the above-described problems. An object of the present invention is to provide a pneumatic tire for a motorcycle having a novel configuration.

  The first feature of the present invention (the feature of the invention described in claim 1) is that a pair of bead portions each having a bead core and a carcass layer provided so as to extend in a toroidal shape between the pair of bead cores. And a pneumatic tire for a motorcycle comprising a tread portion provided on the outer side in the tire radial direction of the crown portion in the carcass layer, and sidewall portions provided on both sides of the tread portion in the carcass layer, A spiral belt layer provided between the carcass layer and the tread portion and formed by spirally winding a ribbon-like strip material formed by covering a belt cord with rubber in the tire circumferential direction; and the spiral belt layer Are provided so as to be covered with the tread portion, and extend inclined with respect to the tire circumferential direction. A split inclined belt layer formed by covering several belt belt cords with rubber, and a ribbon-like strip provided on the center side portion of the spiral belt layer so as to be covered with the tread portion, and covering the belt cord with rubber And an auxiliary spiral belt layer formed by spirally winding the material in the tire circumferential direction.

  According to the first feature, the spiral belt layer is formed by spirally winding a ribbon-shaped strip material formed by covering a belt cord with rubber in the tire circumferential direction. The protrusion to the outer side in the tire radial direction can be suppressed, and high-speed durability can be improved.

  In addition, the divided inclined belt layer is provided on each of the pair of shoulder side portions of the spiral belt layer, in other words, the pair of shoulder regions of the tread portion is reinforced by the spiral belt layer and the divided inclined belt layer. Therefore, the bending rigidity of the pair of shoulder regions of the tread portion can be increased to improve the grip performance (grip force) during turning, and the turning stability can be improved.

  Further, the auxiliary spiral belt layer is provided on the center side portion of the spiral belt layer so as to be covered with the tread portion, and the auxiliary spiral belt layer is a ribbon formed by coating a belt cord with rubber like the spiral belt layer. Is formed by spirally winding a strip-shaped strip material in the tire circumferential direction, so that a sufficient contact width of the tread portion during straight running is ensured and the straight running stability is improved, while the tread portion is improved. The rigidity step between the center region and the shoulder region can be reduced.

  A second feature of the present invention (a feature of the invention described in claim 2) is that, in addition to the first feature, the end portion on the tire equatorial plane side of each of the divided inclined belt layers is within a ground contact region during straight running. The gist is that they are located respectively.

  According to the invention described in claim 1 or claim 2, after improving the high speed durability, the straight running stability, and the turning stability, the rigid step between the center region and the shoulder region is formed in the tread portion. Therefore, when moving from the straight traveling state to the turning traveling state or from the turning traveling state to the straight traveling state, the linearity of the ground contact feeling and the rigidity feeling can be improved and stable traveling can be performed.

  An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  Here, FIG. 1 is a sectional view of a pneumatic tire for a motorcycle according to an embodiment of the present invention, and FIG. 2 is a development view of a carcass layer, a spiral belt layer, a split inclined belt layer, and an auxiliary spiral belt layer.

  As shown in FIGS. 1 and 2, a pneumatic tire 1 for a motorcycle according to an embodiment of the present invention is assembled to a rim (not shown) and includes a pair of bead portions 3. Each bead portion 3 includes a bead core 5 and a bead filler 7 disposed outside the bead core 5 in the tire radial direction R.

  A carcass layer 9 is provided between the pair of bead cores 5 so as to extend in a toroidal shape, and the carcass layer 9 is formed by covering a plurality of carcass cords 11 with rubber. Here, the carcass cord 11 is an organic fiber cord such as a nylon cord, for example. Further, both end portions of the carcass layer 9 are moored so that the corresponding bead cores 5 are folded back from the inner side in the tire width direction W to the outer side in the tire width direction W.

  A tread portion 13 is provided on the outer side in the tire radial direction R of the crown portion in the carcass layer 9, and a plurality of grooves 15 are appropriately formed on the surface of the tread portion 13. Here, the center region of the tread portion 13 is located in the ground contact region during straight traveling, and the shoulder region of the tread portion 13 is located in the ground contact region during turning travel. Further, sidewall portions 17 are provided on both sides of the tread portion 13 in the carcass layer 9, and an inner liner 19 is provided on the inner side surface of the carcass layer 9.

  A spiral belt layer 21 is provided between the carcass layer 9 and the tread portion 13, and the spiral belt layer 21 is formed of one or more belt cords 23 extending substantially in the tire circumferential direction C. The ribbon-shaped strip material which coat | covers is formed by winding in the tire circumferential direction C spirally. Here, the belt cord 23 may be an organic fiber cord or a steel cord.

  The pair of shoulder side portions of the spiral belt layer 21 are provided with the divided inclined belt layer 25 so as to be covered with the tread portion 13, and the divided inclined belt layer 25 is inclined with respect to the tire circumferential direction C. A plurality of extending belt cords 27 are covered with rubber. Here, the belt cord 27 may be an organic fiber cord or a steel cord. Further, the end portion of each divided inclined belt layer 25 on the tire equatorial plane S side is located in a ground contact area during straight traveling.

  An auxiliary spiral belt layer 29 is provided at the center side portion of the spiral belt layer 21 so as to be covered with the tread portion 13, and the auxiliary spiral belt layer 29 covers one or a plurality of belt cords 31 with rubber. The ribbon-shaped strip material is formed by spirally winding in the tire circumferential direction C. Here, the belt cord 31 may be an organic fiber cord or a steel cord.

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  Since the spiral belt layer 21 is formed by spirally winding a ribbon-shaped strip material in which the belt cord 23 is covered with rubber in the tire circumferential direction C, the outer side in the tire radial direction R of the tread portion 13 during high speed running. It is possible to suppress the protrusion to the surface and to improve the high speed durability.

  Further, the divided inclined belt layer 25 is provided on each of the pair of shoulder sides of the spiral belt layer 21. In other words, the pair of shoulder regions of the tread portion 13 is reinforced by the spiral belt layer 21 and the divided inclined belt layer 25. Therefore, the bending rigidity of the pair of shoulder regions of the tread portion 13 can be increased, the grip property (grip force) during turning can be improved, and the turning stability can be improved.

  Further, an auxiliary spiral belt layer 29 is provided at the center side portion of the spiral belt layer 21 so as to be covered with the tread portion 13, and the auxiliary spiral belt layer 29 is formed by covering a belt cord 31 with rubber like the spiral belt layer 21. Since the ribbon-shaped strip material is spirally wound in the tire circumferential direction C, the tread portion 13 is sufficiently secured in contact with the tread portion 13 during straight running, thereby improving the straight running stability. The rigidity step between the center region and the shoulder region in the portion 13 can be reduced.

  As described above, according to the embodiment of the present invention, the rigidity step between the center region and the shoulder region is reduced in the tread portion 13 while improving the high speed durability, the straight traveling stability, and the turning stability. Therefore, when moving from the straight traveling state to the turning traveling state or from the turning traveling state to the straight traveling state, linearity of the ground feeling and the rigidity feeling can be improved and stable traveling can be performed. In particular, since the end portion of each divided inclined belt layer 25 on the tire equatorial plane S side is positioned within the ground contact area during straight traveling, when the straight traveling state is changed to the turning traveling state or the turning traveling state When moving from straight to a straight running state, it is possible to further improve the linearity of the grounding feeling and the rigidity feeling.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, In addition, it can implement in a various aspect. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

  First, before describing the specific contents of the example, the pneumatic tire for a motorcycle according to the first and second comparative examples will be briefly described with reference to FIGS. 3 and 4. Here, FIG. 3 is a cross-sectional view of a pneumatic tire for a motorcycle according to a first comparative example, and FIG. 4 is a cross-sectional view of the pneumatic tire for a motorcycle according to a second comparative example.

  As shown in FIGS. 3 and 4, the pneumatic tire 33 according to the first comparative example omits the divided inclined belt layer 25 and the auxiliary spiral belt layer 29 in the pneumatic tire 1 for a motorcycle according to the embodiment of the present invention. This corresponds to the pneumatic tire for a motorcycle according to the first prior art in the description of the background art. Further, in the pneumatic tire 35 according to the second comparative example, the auxiliary spiral belt layer 29 in the pneumatic tire 1 for a motorcycle according to the embodiment of the present invention is omitted, and the second in the description of the background art is omitted. It corresponds to a pneumatic tire for a motorcycle according to the prior art. The general configuration of the pneumatic tires 33 and 35 according to the first and second comparative examples is substantially the same as the general configuration of the pneumatic tire 1 for a motorcycle according to the embodiment of the present invention, Of the plurality of components in the pneumatic tires 33 and 35 for motorcycles according to the first and second comparative examples, those corresponding to the components in the pneumatic tire 1 for motorcycles according to the embodiment of the present invention are shown in FIG. The same number is attached in the inside and description is abbreviate | omitted.

  Subsequently, specific contents of the embodiment will be described.

The pneumatic tire 1 for a motorcycle according to the embodiment of the present invention is used as an invention, the pneumatic tire 33 for a motorcycle according to a first comparative example is used as a comparative product 1, and the pneumatic tire 35 for a motorcycle according to a second comparative example is used. Was made as a comparative product 2 with a tire size of 190 / 50ZR17M / C (73W). Next, the inventive product, the comparative product 1 and the comparative product 2 are assembled to a rim of 17 M / C × 6.00 and mounted as rear tires for a motorcycle. The trained riders drive the two-wheeled vehicle equipped with the invention, comparative product 1 and comparative product 2 respectively, so that straight running stability, grip performance (grip force) during turning, and straight running state are achieved. An actual vehicle test was conducted on the linearity of the ground contact feeling when transitioning to a turning state (or a transition from a turning state to a straight traveling state. Furthermore, the feeling evaluation (average value of multiple riders) as a result of the test was performed. Summarized by the index display, it will be as shown in Table 1 below.In addition, as the index of linearity stability, grip performance during turning, and linearity of the feeling of ground contact, the straightness stability, grip performance during turning, and The linearity of the feeling of grounding is good respectively.

  In other words, as shown in Table 1, the inventive product improves linearity of the feeling of grounding compared with the comparative product 1 and the comparative product 2 while improving the straight running stability and the grip property at the time of turning to the same level as the comparative product 2. I was able to.

1 is a cross-sectional view of a pneumatic tire for a motorcycle according to an embodiment of the present invention. It is an expanded view of a carcass layer, a spiral belt layer, a division | segmentation inclination belt layer, and an auxiliary | assistant spiral belt layer. It is sectional drawing of the pneumatic tire for two-wheeled vehicles which concerns on a 1st comparative example. It is sectional drawing of the pneumatic tire for two-wheeled vehicles which concerns on a 2nd comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire for two-wheeled vehicles 3 Bead part 9 Carcass layer 13 Tread part 17 Side wall part 21 Spiral belt layer 23 Belt cord 25 Divided inclined belt layer 27 Belt cord 29 Auxiliary spiral belt layer 31 Belt cord

Claims (2)

A pair of bead portions each having a bead core; a carcass layer provided to extend in a toroidal shape between the pair of bead cores; and a tread portion provided on the outer side in the tire radial direction of the crown portion of the carcass layer; In the pneumatic tire for a motorcycle, comprising a sidewall portion provided on both sides of the tread portion in the carcass layer,
A spiral belt layer formed between the carcass layer and the tread portion and formed by spirally winding a ribbon-like strip material formed by covering a belt cord with rubber in the tire circumferential direction;
A split inclined belt layer formed by rubber-covering a plurality of belt cords provided to be covered with the tread portion on a pair of shoulder side portions of the spiral belt layer and extending inclined with respect to the tire circumferential direction;
Auxiliary spiral belt formed by spirally winding a ribbon-shaped strip material formed by covering a belt cord with rubber at a center side portion of the spiral belt layer in a tire circumferential direction. Layers,
A pneumatic tire for a motorcycle, characterized by comprising:   2. The pneumatic tire for a motorcycle according to claim 1, wherein an end portion of each of the divided inclined belt layers on a tire equatorial plane side is positioned in a ground contact area during straight traveling.

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