JP2022165795A - Motorcycle tires and tire sets - Google Patents

Abstract

An object of the present invention is to provide a motorcycle tire capable of achieving both drainage performance and durability.
SOLUTION: This motorcycle tire 1 is manufactured using a pair of molds that are divided in the tire axial direction. A motorcycle tire 1 has a tread portion 2 in which a plurality of grooves 3 are formed. The tread portion 2 is provided with a pair of mold splitting positions P at positions that do not intersect the grooves 3 .
[Selection diagram] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a motorcycle tire manufactured using a pair of molds split in the tire axial direction.

2. Description of the Related Art Conventionally, a motorcycle tire having a tread portion provided with a plurality of grooves for drainage is known. For example, Patent Literature 1 below proposes a motorcycle tire in which a tread portion is provided with a main oblique groove, a sub oblique groove, and a center main groove.

JP 2014-131899 A

Motorcycle tires such as those disclosed in Patent Document 1 are generally manufactured using a pair of molds that are split in the tire axial direction. However, in the motorcycle tire of Patent Document 1, cracks may occur at the bottom of the groove at the intersections of the splitting positions of the pair of molds and the grooves of the tread portion, or rubber may be caught in the splitting positions. In some cases, a film was formed that prevented drainage.

SUMMARY OF THE INVENTION The present invention has been devised in view of the actual situation as described above, and a main object of the present invention is to provide a tire for a motorcycle that can achieve both drainage performance and durability.

The present invention provides a motorcycle tire manufactured using a pair of molds divided in the tire axial direction, the tire having a tread portion formed with a plurality of grooves, the tread portion having the grooves. The splitting position of the pair of molds is provided at a position that does not intersect the two.

In the motorcycle tire of the present invention, the axial distance between the groove wall of the groove closest to the split position and the split position is preferably 1 to 10 mm.

In the motorcycle tire of the present invention, it is preferable that the groove includes a pair of inclined grooves extending in a direction inclined with respect to the tire circumferential direction across the tire equator.

In the motorcycle tire of the present invention, it is preferable that the rotation direction of the tire is specified, and the distance of the inclined groove from the tire equator gradually increases from the first arrival side to the last arrival side in the rotation direction.

In the motorcycle tire of the present invention, it is preferable that the angle of the inclined groove with respect to the tire circumferential direction is smaller on the first-arriving side in the rotational direction than on the last-arriving side.

In the motorcycle tire of the present invention, it is desirable that the axial length of the longest inclined groove is 50% or more of the half width of the tread.

In the motorcycle tire of the present invention, it is preferable that 15 to 29 pairs of inclined grooves are formed in the tire circumferential direction.

In the motorcycle tire of the present invention, the groove preferably includes a circumferential groove extending in the tire circumferential direction on the tire equator.

In the motorcycle tire of the present invention, it is preferable that the circumferential groove extends in a zigzag shape including bent portions arranged on one side and the other side of the tire equator and connecting portions connecting the bent portions. .

In the motorcycle tire of the present invention, it is preferable that the bent portion includes a shallow groove portion in which the groove depth gradually decreases.

In the motorcycle tire of the present invention, it is desirable that the split position is provided at a position away from the tire equator.

In the motorcycle tire of the present invention, the distance between the split position and the tire equator is preferably 5% to 20% of the tread half width.

In the motorcycle tire of the present invention, it is desirable that the groove is not provided on the tire equator.

The present invention is a tire set comprising a front tire and a rear tire to be mounted on a motorcycle, wherein the front tire is the one motorcycle tire described above, and the rear tire is the other motorcycle tire described above. It is characterized by being a tire for a motorcycle.

A motorcycle tire of the present invention has a tread portion in which a plurality of grooves are formed, and the tread portion is provided with a pair of mold splitting positions at positions that do not cross the grooves. In such a motorcycle tire, the splitting position of the mold does not intersect with the groove of the tread portion, so cracks at the bottom of the groove can be suppressed and durability can be improved.

Further, in this motorcycle tire, even if rubber is caught in the split position, no film is formed in the grooves, so there is no risk of deterioration in drainage performance. Therefore, the motorcycle tire of the present invention can achieve both drainage performance and durability.

1 is an exploded view showing an embodiment of a tread portion of a motorcycle tire of the present invention; FIG. It is an enlarged view of a circumferential groove. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; FIG. 3 is a cross-sectional view taken along line BB of FIG. 2; FIG. 5 is a developed view showing a tread portion of a motorcycle tire of another embodiment.

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a developed view showing a tread portion 2 of a motorcycle tire 1 of this embodiment. As shown in FIG. 1, a motorcycle tire 1 of this embodiment has a tread portion 2 including a tread surface 2a that contacts the road surface during running. The motorcycle tire 1 of the present embodiment is suitably used as a front wheel tire of a motorcycle. A plurality of grooves 3 are formed in the tread portion 2 of this embodiment.

The motorcycle tire 1 of this embodiment is manufactured using a pair of molds (not shown) that are divided in the tire axial direction. For this reason, the tread portion 2 of the present embodiment is provided with a pair of die splitting positions P. As shown in FIG. The split position P of this embodiment is provided at a position that does not intersect the groove 3 .

In such a motorcycle tire 1, the splitting position P of the mold and the grooves 3 of the tread portion 2 do not intersect, so cracks at the bottom of the groove can be suppressed and durability can be improved. Further, in the motorcycle tire 1, even if rubber is caught in the splitting position P, a film is not formed in the grooves 3, so there is no risk of deterioration in drainage performance. Therefore, the motorcycle tire 1 of the present embodiment can achieve both drainage performance and durability.

As a more preferable aspect, the motorcycle tire 1 has a specified tire rotation direction R. As shown in FIG. Such a motorcycle tire 1 can be provided with the grooves 3 corresponding to the tire rotation direction R, and can improve drainage performance.

The grooves 3 of this embodiment include a pair of inclined grooves 4 extending in a direction inclined with respect to the tire circumferential direction across the tire equator C, and a circumferential groove 5 extending in the tire circumferential direction on the tire equator C. I'm in. Such grooves 3 can further improve the drainage performance of the motorcycle tire 1 by the inclined grooves 4 and the circumferential grooves 5 . Moreover, since such a circumferential groove 5 is provided on the tire equator C, the turning response from the time of upright rolling is good, and the handling performance of the motorcycle tire 1 can be improved.

The slanted groove 4 includes, for example, a first slanted groove 4A, a second slanted groove 4B, a third slanted groove 4C, and a fourth slanted groove 4D having different groove widths and lengths. The inclined grooves 4 are not limited to such a mode, and can be provided by appropriately changing the number of types, groove width, length and shape, for example.

It is desirable that the distance L1 from the tire equator C of the inclined groove 4 gradually increases from the first arrival side in the rotation direction R to the last arrival side. Here, the distance L1 is the axial distance of the tread portion 2 in the developed view. Such inclined grooves 4 can facilitate the drainage of the contact surface by rolling, and can improve the drainage performance of the motorcycle tire 1 .

The angle θ of the inclined groove 4 with respect to the tire circumferential direction is desirably smaller on the first arrival side in the rotation direction R than on the last arrival side. Here, the angle θ is the angle with respect to the tire circumferential direction in the developed view of the tread portion 2 . Such inclined grooves 4 can further promote drainage of the ground contact surface during upright rolling, and can improve the drainage performance of the motorcycle tire 1 .

The axial length L2 of the longest inclined groove 4 is preferably 50% or more of the tread half width W. In this embodiment, the first inclined groove 4A is the longest inclined groove 4. As shown in FIG. Here, the length L2 is the axial length of the tread portion 2 in the developed view, and the tread half width W is the axial width of the tread portion 2 from the tire equator C to the tread end Te. is.

In such a motorcycle tire 1, the long inclined grooves 4 promote drainage from the ground contact surface and improve drainage performance. From this point of view, the length L2 is more preferably 70% or more of the tread half width W, and still more preferably 90% or more of the tread half width W.

The motorcycle tire 1 preferably has 15 to 29 pairs of inclined grooves 4 formed in the tire circumferential direction. In this embodiment, 15 to 29 pairs of first inclined grooves 4A, second inclined grooves 4B, third inclined grooves 4C, and fourth inclined grooves 4D are formed in the tire circumferential direction. Such a motorcycle tire 1 is suitable for achieving both drainage performance and durability, and the rigidity of the tread portion 2 can be optimized, so that handling performance can also be improved.

The circumferential groove 5 of the present embodiment includes bent portions 5a arranged on one side and the other side of the tire equator C, and connecting portions 5b connecting the bent portions 5a. Therefore, the circumferential grooves 5 of this embodiment extend in a zigzag shape in the tire circumferential direction. Such a motorcycle tire 1 can improve the drainage performance of the circumferential grooves 5 and prevent the water film from being pushed forward in the direction of travel, resulting in poor visibility. In addition, the circumferential groove 5 may, for example, extend linearly in the tire circumferential direction, or may extend in a wavy shape.

2 is an enlarged view of the circumferential groove 5, FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, and FIG. 4 is a cross-sectional view taken along the line BB of FIG. As shown in FIGS. 2 to 4, the bent portion 5a of the circumferential groove 5 of this embodiment includes a shallow groove portion 5c with a gradually decreasing groove depth.

Such a shallow groove portion 5c promotes drainage in the bent portion 5a, and can improve the drainage performance of the tire 1 for a motorcycle. Further, since the depth of the shallow groove portion 5c gradually changes, it is possible to suppress a decrease in the rigidity of the ground contact surface during upright rolling, thereby improving the durability of the motorcycle tire 1. can.

The shallow groove portion 5c is desirably provided on the later arrival side in the rotation direction R. As shown in FIG. Such a shallow groove portion 5c can also facilitate drainage of the connection portion 5b on the first-arrival side in the rotation direction R, and can further improve the drainage performance of the motorcycle tire 1. As shown in FIG. In addition, the shallow groove portion 5c optimizes the rigidity of the tread portion 2 and helps improve the handling performance of the tire 1 for motorcycles.

As shown in FIG. 1, the split position P is provided at a position away from the tire equator C, for example. The split position P is desirably provided on the upper mold side of the pair of upper and lower molds. The split position P of this embodiment is provided between the inclined groove 4 and the circumferential groove 5 . Such a motorcycle tire 1 can suppress crossing of the split position P with the inclined grooves 4 and the circumferential grooves 5, and can achieve both drainage performance and durability.

The distance L3 between the split position P and the tire equator C is preferably 5% to 20% of the tread half width W. Here, the distance L3 is the axial distance of the tread portion 2 in the developed view. When the distance L3 is 5% or more of the tread half width W, it is possible to suppress the intersection of the split position P and the circumferential groove 5, and improve the durability of the motorcycle tire 1. From this point of view, the distance L3 is more preferably 6% or more of the tread half width W, and still more preferably 7% or more.

Since the distance L3 is 20% or less of the tread half width W, undercutting at the tire equator C can be suppressed, and it is possible to easily remove the tire from the mold. From this point of view, the distance L3 is more preferably 16% or less of the tread half width W, and still more preferably 12% or less.

The axial distances d1 and d2 between the groove wall of the groove 3 closest to the split position P and the split position P are preferably 1 to 10 mm. Here, the distances d1 and d2 are distances in the axial direction of the tread portion 2 in the developed view. The distances d1 and d2 include, for example, a first distance d1 on one side of the split position P in the tire axial direction and a second distance d2 on the other side.

The first distance d1 in this embodiment is the distance between the split position P and the circumferential groove 5 in the axial direction of the tire. The second distance d2 in this embodiment is the axial distance between the split position P and the first inclined groove 4A. The first distance d1 and the second distance d2 may be the same or different.

When the distances d1 and d2 are 1 mm or more, the intersection of the split position P and the groove 3 can be reliably avoided, and the durability of the motorcycle tire 1 can be improved. From this point of view, the distances d1 and d2 are more preferably 2 mm or more, and still more preferably 3 mm or more.

By setting the distances d1 and d2 to 10 mm or less, it is possible to reduce the area where the grooves 3 do not exist and improve the drainage performance of the motorcycle tire 1 . From this point of view, the distances d1 and d2 are more preferably 8 mm or less, and even more preferably 6 mm or less.

FIG. 5 is a developed view showing a tread portion 12 of a motorcycle tire 11 of another embodiment. As shown in FIG. 5, the motorcycle tire 11 of this embodiment has a tread portion 12 including a tread surface 12a that comes into contact with the road surface during running, like the motorcycle tire 1 described above. The motorcycle tire 11 of this embodiment is suitably used as a rear wheel tire of a motorcycle. A plurality of grooves 13 are formed in the tread portion 12 of this embodiment, as in the tread portion 2 described above.

The motorcycle tire 11 of this embodiment is manufactured using a pair of molds (not shown) divided in the tire axial direction, similarly to the motorcycle tire 1 described above. For this reason, the tread portion 12 of this embodiment is also provided with a pair of mold splitting positions P. As shown in FIG. The split position P in this embodiment is also provided at a position that does not intersect the groove 13 .

In such a motorcycle tire 11, the splitting position P of the mold and the groove 13 of the tread portion 12 do not intersect, so cracks at the bottom of the groove can be suppressed and durability can be improved. Further, in the motorcycle tire 11, even if rubber is caught in the split position P, no film is formed in the grooves 13, so there is no risk of deterioration in drainage performance. Therefore, the motorcycle tire 1 of this embodiment can achieve both drainage performance and durability, like the motorcycle tire 1 described above.

As with the motorcycle tire 1 described above, the motorcycle tire 11 of this embodiment has a designated rotation direction R of the tire. Such a motorcycle tire 11 can be provided with the grooves 13 corresponding to the tire rotation direction R, and can improve drainage performance.

The grooves 13 of this embodiment include a pair of inclined grooves 14 that sandwich the tire equator C and extend in a direction that is inclined with respect to the tire circumferential direction. The slanted groove 14 includes, for example, a first slanted groove 14A, a second slanted groove 14B, a third slanted groove 14C and a fourth slanted groove 14D having different groove widths and lengths. The inclined grooves 14 are not limited to such a mode, and for example, the number of types, groove width, length and shape can be appropriately changed.

It is desirable that the distance L1 of the inclined groove 14 from the tire equator C gradually increases from the first-arriving side to the last-arriving side in the rotational direction R, similarly to the above-described inclined grooves 4 . Such inclined grooves 14 can facilitate the drainage of the contact surface by rolling, and can improve the drainage performance of the motorcycle tire 11 .

The angle θ of the inclined groove 14 with respect to the tire circumferential direction is desirably smaller on the first-arriving side in the rotational direction R than on the last-arriving side, similarly to the above-described inclined groove 4 . Such inclined grooves 14 can further promote drainage of the ground contact surface during upright rolling, and can improve the drainage performance of the motorcycle tire 11 .

The length L2 of the longest inclined groove 14 in the tire axial direction is preferably 50% or more of the tread half width W, more preferably 70% or more of the tread half width W, similarly to the above-described inclined groove 4, More preferably, it is 90% or more of the tread half width W. In this embodiment, the first inclined groove 14A is the longest inclined groove 14 as well. In such a motorcycle tire 11, the long inclined grooves 14 promote drainage from the ground contact surface and improve drainage performance.

The groove 13 in this embodiment is not provided on the tire equator C. Such a motorcycle tire 1 can disperse the distortion of the ground contact surface during upright rolling even when used as a rear wheel tire to which a high load is applied, thereby improving wear resistance. can be done.

The split position P in this embodiment is provided on the tire equator C. As shown in FIG. The split position P may be provided at a position away from the tire equator C, for example. When the splitting position P is provided at a position away from the tire equator C, it is desirable that the splitting position P is provided on the upper die side of the pair of upper and lower molds. The split position P of this embodiment is provided between the inclined groove 14 on one side of the tire equator C and the inclined groove 14 on the other side. Such a motorcycle tire 11 can suppress crossing of the split position P and the groove 13, and can achieve both drainage performance and durability.

The distance L3 between the split position P and the tire equator C is preferably 20% or less of the tread half width W. Since the distance L3 is 20% or less of the tread half width W, undercutting at the tire equator C can be suppressed, and it is possible to easily remove the tire from the mold. From this point of view, this distance is more preferably 16% or less of the tread half width W, and still more preferably 12% or less.

The axial distances d1 and d2 between the groove wall of the groove 3 closest to the split position P and the split position P are preferably 1 to 10 mm. Here, the distances d1 and d2 are distances in the axial direction of the tread portion 2 in the developed view. The distances d1 and d2 include, for example, a first distance d1 on one side of the split position P in the tire axial direction and a second distance d2 on the other side.

The first distance d1 in this embodiment is the axial distance between the split position P and the first inclined groove 14A on one side of the split position P in the tire axial direction. The second distance d2 in this embodiment is the axial distance between the split position P and the first inclined groove 14A on the other side of the split position P in the tire axial direction. The first distance d1 and the second distance d2 may be the same or different.

When the distances d1 and d2 are 1 mm or more, the intersection of the split position P and the groove 3 can be reliably avoided, and the durability of the motorcycle tire 1 can be improved. From this point of view, the distances d1 and d2 are more preferably 2 mm or more, and still more preferably 3 mm or more.

By setting the distances d1 and d2 to 10 mm or less, it is possible to reduce the area where the grooves 3 do not exist and improve the drainage performance of the motorcycle tire 1 . From this point of view, the distances d1 and d2 are more preferably 8 mm or less, and even more preferably 6 mm or less.

As shown in FIGS. 1 and 5, motorcycle tires 1 and 11 are preferably used as a tire set including a front tire and a rear tire mounted on a motorcycle, for example. The front tire of this embodiment is the motorcycle tire 1 shown in FIG. Further, the rear wheel tire of this embodiment is a motorcycle tire 11 shown in FIG.

In such a tire set, the motorcycle tire 1 including the circumferential grooves 5 is mounted on the front wheel tire for steering, so excellent drainage can be achieved. Further, in this tire set, the motorcycle tire 11 having no groove 13 on the tire equator C is mounted on the rear wheel tire to which a high load is applied, so excellent durability can be exhibited. Therefore, the tire set of this embodiment can achieve both drainage performance and durability.

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and can be implemented in various modified forms.

Motorcycle tires having the tread portions shown in FIGS. 1 and 5 were produced as prototypes based on the specifications shown in Tables 1 and 2, respectively. As a comparative example, a motorcycle tire having grooves identical to the inclined grooves of the tread portion shown in FIGS. Using a prototype motorcycle tire, drainage performance, durability and handling performance were tested. Main common specifications and test methods are as follows.

<Common specifications>
Front tire: Motorcycle tire having the tread shown in Figure 1 Front tire size: 110/70-13M/C
Front wheel rim size: 13×3.00MT
Rear tire: Motorcycle tire having the tread shown in Fig. 5 Rear tire size: 130/70-13M/C
Rear wheel rim size: 13×3.50MT

<Drainability>
The tires were mounted on the front and rear wheels of a medium-sized scooter with the air pressure of the front tires set to 200 kPa and the air pressure of the rear tires set to 225 kPa, and the water drainage performance was evaluated by a test driver on a scale of 1 to 10. rice field. A similar test was conducted by 20 test drivers and their total points were calculated. The results are expressed as an index with the total score of Comparative Examples being 100, and the larger the number, the better the drainage.

<Durability>
Set the air pressure of the rear tire to 280 kPa and mount it on the drum tester, load it with a load of 2.67 kN and run it for 4 hours, then load it with a load of 2.89 kN and run it for 6 hours, and further 3.13 kN. The state of cracks was evaluated after running for 24 hours with a load of . The results are expressed as an index with the comparative example being 100, and the larger the numerical value, the more excellent the durability.

<Handling performance>
The tires were mounted on the front and rear wheels of a medium-sized scooter with front tire pressure of 200 kPa and rear tire pressure of 225 kPa. rice field. A similar test was conducted by 20 test drivers and their total points were calculated. The results are expressed as an index with the total score of Comparative Examples being 100, and the larger the number, the better the handling performance.

The results of the tests are shown in Tables 1 and 2.

As a result of the test, it was confirmed that the tires for motorcycles of Examples are superior in drainage performance and durability to Comparative Examples, and have both drainage performance and durability.

1 motorcycle tire 2 tread portion 3 groove

Claims (14)

A motorcycle tire manufactured using a pair of molds divided in the tire axial direction,
Having a tread portion in which a plurality of grooves are formed,
The tread portion is provided with a pair of split positions for the molds at positions that do not intersect the grooves.
Motorcycle tires. The motorcycle tire according to claim 1, wherein the axial distance between the groove wall of the groove closest to the split position and the split position is 1 to 10 mm. The motorcycle tire according to claim 1 or 2, wherein the groove includes a pair of inclined grooves extending in a direction inclined with respect to the tire circumferential direction across the tire equator. The direction of rotation of the tire is specified,
The motorcycle tire according to claim 3, wherein the distance of said inclined groove from the tire equator gradually increases from the first arrival side to the last arrival side in the rotational direction. The motorcycle tire according to claim 4, wherein an angle of the inclined groove with respect to the tire circumferential direction is smaller on the first-arriving side in the rotational direction than on the last-arriving side. The motorcycle tire according to any one of claims 3 to 5, wherein the axial length of the longest inclined groove is 50% or more of the tread half width. The motorcycle tire according to any one of claims 3 to 6, wherein 15 to 29 pairs of said inclined grooves are formed in the tire circumferential direction. The motorcycle tire according to any one of claims 1 to 7, wherein the groove includes a circumferential groove extending in the tire circumferential direction on the tire equator. 9. The motorcycle tire according to claim 8, wherein the circumferential groove extends in a zigzag shape including bent portions arranged on one side and the other side of the tire equator and connecting portions connecting the bent portions. The motorcycle tire according to claim 9, wherein the bent portion includes a shallow groove portion whose groove depth gradually decreases. The motorcycle tire according to any one of claims 8 to 10, wherein the split position is provided at a position away from the tire equator. The motorcycle tire according to claim 11, wherein the distance between the split position and the tire equator is 5% to 20% of the tread half width. The motorcycle tire according to any one of claims 1 to 7, wherein the groove is not provided on the tire equator. A tire set comprising a front wheel tire and a rear wheel tire mounted on a motorcycle,
The front tire is the motorcycle tire according to any one of claims 8 to 12,
A tire set, wherein the rear tire is the motorcycle tire according to claim 13 .

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