JP7427963B2 - motorcycle tires - Google Patents

Description

The present invention relates to a motorcycle tire.

Patent Document 1 listed below describes a pneumatic tire for a motorcycle for traveling on rough terrain that has a tread portion. The tread portion is provided with a crown block arranged on the tire equator. The crown block has an oblong block body and a protrusion projecting from the block body.

Patent No. 6047131

Since the convex portion is provided in a cantilevered manner on the block main body, the tip of the convex portion is more easily deformed than the base portion during running, and the rigidity decreases due to fatigue during running. There is also a risk. For this reason, there is room for further improvement in the traction performance and anti-skid performance of the above two-wheeled vehicle tires.

The present invention was devised in view of the above-mentioned circumstances, and an object of the present invention is to provide a two-wheeled vehicle tire that can further improve traction performance and anti-skid performance.

The present invention provides a two-wheeled vehicle tire, in which a tread portion is provided with a plurality of blocks, the plurality of blocks includes at least one finned block, and the finned block has a block body portion, at least one fin part protruding from the block main body in the tire circumferential direction, the fin part including a root part connected to the block main body part, and a tip part on the opposite side of the root part, The width of the tip portion in the tire axial direction is larger than the width of the root portion in the tire axial direction.

In the two-wheeled vehicle tire according to the present invention, it is preferable that the tread portion has a specified rotation direction, and the fin portion protrudes from the block main body portion toward the rear side in the rotation direction.

In the motorcycle tire according to the present invention, it is preferable that the length of the fin portion in the tire circumferential direction is 0.5 times or more the length of the block body portion in the tire circumferential direction.

In the motorcycle tire according to the present invention, it is preferable that the width of the fin portion in the tire axial direction is 0.05 to 0.2 times the width of the block body portion in the tire axial direction.

In the two-wheeled vehicle tire according to the present invention, it is desirable that the width of the fin portion in the tire axial direction continuously increases toward the tip end.

In the two-wheeled vehicle tire according to the present invention, the fin portion includes an end-side fin portion disposed at at least one of both ends of the block body portion in the tire axial direction, and the end-side fin portion extends in the tire circumferential direction. It has a pair of extending edges, the pair of edges include an outer edge and an inner edge disposed closer to the center of the block body in the tire axial direction than the outer edge, and the inner edge includes: It is preferable that the tire be inclined toward the center of the block main body in the tire axial direction toward the tip.

In the motorcycle tire according to the present invention, it is desirable that the angle of the inner edge with respect to the tire circumferential direction is 45 degrees or less.

In the two-wheeled vehicle tire according to the present invention, it is preferable that the outer edge slopes toward the tip end in a direction opposite to the inner edge.

In the motorcycle tire according to the present invention, it is desirable that the angle of the outer edge with respect to the tire circumferential direction is 45 degrees or less.

In the two-wheeled vehicle tire according to the present invention, it is preferable that the fin portion includes a pair of end-side fin portions disposed at both ends of the block main body portion in the tire axial direction.

In the motorcycle tire according to the present invention, the shortest distance in the tire axial direction between the inner edges of the pair of end side fin portions is 0.15 to 0.75 times the width of the block body portion in the tire axial direction. It is desirable that

In the two-wheeled vehicle tire according to the present invention, it is preferable that the block height of the inner edge of the end-side fin portion is smaller than the block height of the outer edge at the tip portion.

In the motorcycle tire according to the present invention, the block includes at least two finned blocks adjacent in the tire axial direction, and the fin interval between these finned blocks is 50% or more of the block body interval. It is desirable that

In the fin portion of the present invention, the width of the tip portion in the tire axial direction is larger than the width of the root portion in the tire axial direction, so that the tip portion has high rigidity. Therefore, for example, when the vehicle is traveling straight, the fin portion effectively suppresses the collapse of the block main body portion upon contact with the ground. This helps the block body and fins penetrate deeply into the road surface, which in turn improves traction performance.

Further, in the fin portion configured as described above, deformation of the tip portion is suppressed even during cornering. This causes the edge of the fin portion in the tire circumferential direction to properly contact the road surface, thereby exhibiting excellent anti-skid performance.

Further, in the fin portion configured as described above, the rigidity of the tip portion is prevented from decreasing early due to fatigue caused by running, and the above-mentioned effect is maintained for a long period of time.

1 is a sectional view showing an embodiment of a two-wheeled vehicle tire of the present invention. FIG. 3 is a plan view of the finned block. FIG. 3 is a plan view of the finned block. FIG. 4 is an end view taken along the line AA in FIG. 3; It is a top view of a tread part. It is a top view of a tread part. It is a top view of the finned block of other embodiments.

Hereinafter, one embodiment of the present invention will be described based on the drawings.
FIG. 1 is a tire meridian cross-sectional view including a tire rotation axis (not shown) in a normal state of a two-wheeled vehicle tire (hereinafter sometimes simply referred to as "tire") 1 according to the present embodiment. It is desirable that the tire 1 be mounted on, for example, a motorcycle (not shown) that is suitable for running on rough terrain such as muddy roads.

The "regular state" is a state in which the tire 1 is mounted on a regular rim (not shown), is adjusted to have a regular internal pressure, and is under no load. In this specification, unless otherwise specified, the dimensions of each part of the tire 1 are values measured under normal conditions.

The above-mentioned "regular rim" is a rim defined for each tire by the standard in the standard system including the standard on which Tire 1 is based, for example, "Standard rim" for JATMA, "Design Rim" for TRA. ", for ETRTO it is "Measuring Rim".

The above-mentioned "regular internal pressure" is the air pressure specified for each tire by each standard in the standard system including the standard on which Tire 1 is based, and in the case of JATMA it is the "maximum air pressure", and in the case of TRA it is the air pressure in the table "TIRE LOAD". The maximum value listed in "LIMITS AT VARIOUS COLD INFLATION PRESSURES" is "INFLATION PRESSURE" for ETRTO.

As shown in FIG. 1, in the tire 1 of this embodiment, the tread surface 2a between the tread ends 2t, 2t of the tread portion 2 extends outward in the tire radial direction in a convex arc shape. In this specification, the distance in the tire axial direction between the tread ends 2t, 2t when the tread portion 2 is developed flatly is defined as the tread development width TW.

The tire 1 includes, for example, a carcass 6 extending between the bead portions 4 on both sides, and a tread reinforcing layer 7 disposed on the outside of the carcass 6 in the tire radial direction. The carcass 6 and the tread reinforcing layer 7 preferably have a known structure.

The tread portion 2 is provided with a plurality of blocks 10. The block 10 is raised from the tread bottom surface 2S. In this specification, the tread bottom surface 2S is a surface between the blocks 10, 10 extending substantially parallel to the carcass 6. The above-mentioned "substantially parallel" means that, for example, small irregularities such as tie bars and depressions provided on the tread bottom surface 2S are excluded.

The block 10 includes at least one finned block 11. FIG. 2 is a plan view of the finned block 11 of this embodiment. As shown in FIG. 2, the finned block 11 of this embodiment includes a block main body portion 12 and at least one fin portion 13 protruding from the block main body portion 12 in the tire circumferential direction.

The fin portion 13 includes a root portion 13A connected to the block main body portion 12, and a tip portion 13B on the opposite side of the root portion 13A. The width (maximum width) wb of the tip portion 13B in the tire axial direction is larger than the width (minimum width) wa of the root portion 13A in the tire axial direction. Thereby, the tip portion 13B has high rigidity. Therefore, for example, when the vehicle is traveling straight, the fin portion 13 effectively suppresses the collapse of the block body portion 12 when it touches the ground. This helps the block body portion 12 and the fin portions 13 to penetrate deeply into the road surface, which in turn improves traction performance. Further, in the fin portion 13 configured in this manner, deformation of the tip portion 13B is suppressed even during cornering. This causes the edge of the fin portion 13 in the tire circumferential direction to properly contact the road surface, thereby exhibiting excellent anti-skid performance. Furthermore, the rigidity of the tip portion 13B of the fin portion 13 is prevented from decreasing early due to fatigue caused by running, and the above-mentioned effect is maintained for a long period of time. In order to effectively exhibit such an effect, the width wb of the tip portion 13B is preferably 1.3 times or more, more preferably 1.4 times or more, and 1.7 times or less than the width wa of the root portion 13A. is desirable, and 1.6 times or less is more desirable.

In the present embodiment, the rotation direction F of the tire 1 is specified in order to maximize the performance of the tread pattern of the tread portion 2. Furthermore, the finned block 11 has, for example, a line-symmetrical shape with respect to the tire circumferential direction line.

The fin portion 13 protrudes from the block main body portion 12 toward the rear-arriving side (hereinafter sometimes simply referred to as the “later-arriving side”) in the rotation direction F. Such a fin portion 13 supports the block main body portion 12 from the rear side and effectively prevents it from collapsing during running.

In this embodiment, the block main body portion 12 has a horizontally elongated shape in which the width (maximum width) W1 in the tire axial direction is larger than the length L1 in the tire circumferential direction. Since such a block main body portion 12 has a large shearing force in the tire circumferential direction, it improves traction performance. The block main body portion 12 has, for example, a substantially V-shaped hexagonal shape with a center portion 12c in the tire axial direction protruding in the tire circumferential direction. In this embodiment, the central portion 12c protrudes toward the rear-arriving side. Note that the shape of the block main body 12 is not limited to a hexagonal shape, and various oblong shapes such as a rectangular shape and a trapezoidal shape may be adopted.

The block main body 12 of this embodiment has a first lateral edge 15 arranged on the first-arriving side (hereinafter sometimes simply referred to as "first-arriving side") in the rotational direction F, and a second lateral edge 15 arranged on the later arriving side. It includes a horizontal edge 16 and a first vertical edge 17 continuous to the first horizontal edge 15. In this embodiment, the first lateral edge 15 and the second lateral edge 16 extend in the tire axial direction. In this embodiment, the first vertical edges 17 are arranged on both sides of the first horizontal edges 15 and extend in the tire circumferential direction. In this specification, "extending in the tire axial direction" refers to an aspect in which the tire axial direction component is larger than the tire circumferential direction component. In this specification, "extending in the tire circumferential direction" refers to an aspect in which the tire circumferential component is larger than the tire axial component. In this embodiment, the first horizontal edge 15, the second horizontal edge 16, and the first vertical edge 17 extend linearly.

The block body 12 includes, for example, a shallow groove 19 extending from the first lateral edge 15 to the second lateral edge 16. The shallow groove 19 of this embodiment is formed in a Y-shape having a first groove part 19a extending from the first lateral edge 15 and branch groove parts 19b branching on both sides from the first groove part 19a. The first groove portion 19a of this embodiment passes through the center portion 12c of the block body portion 12 in the tire axial direction. The branch groove portion 19b of this embodiment is divided from the central portion 12c of the block body portion 12 to both outer sides in the tire axial direction.

In this embodiment, the fin portion 13 and the block main body portion 12 are separated by an imaginary line 16c that extends the second lateral edge 16 smoothly in the tire axial direction. The root portion 13A is formed including a virtual line 16c.

The width W2 of the fin portion 13 in the tire axial direction increases continuously toward the tip portion 13B. Since the change in rigidity of the fin portion 13 is small, the occurrence of wear and uneven wear is suppressed, so that the skid resistance performance is maintained at a high level over a long period of time. In particular, a relatively large lateral force acts on the end-side fin portions 20 disposed at both ends 12e, 12e, so that the above-mentioned effect is effectively exerted.

The length L2 of the fin portion 13 in the tire circumferential direction is 0.5 times or more the length L1 of the block body portion 12 in the tire circumferential direction. Such a fin portion 13 exhibits anti-skid performance and effectively suppresses collapse of the block body portion 12. If the length L2 of the fin portion 13 is excessively large, chipping or cracking may occur at the root portion 13A of the fin portion 13, which may deteriorate skid resistance and traction performance. Therefore, the length L2 of the fin portion 13 is desirably 1.5 times or less the length L1 of the block body portion 12.

The width (maximum width) W2a of the fin portion 13 in the tire axial direction is preferably 0.05 to 0.2 times the width W1 of the block body portion 12 in the tire axial direction. Since the maximum width W2a of the fin portion 13 is 0.05 times or more the width W1 of the block main body portion 12, the rigidity of the fin portion 13 can be increased and wear caused by running can be reduced. Since the maximum width W2a of the fin portion 13 is 0.2 times or less than the width W1 of the block main body portion 12, in the case where two end side fin portions 20, 20 are provided as in this embodiment, the fin portion 13 A large distance in the tire axial direction can be ensured between the fin portion 13 and the fin portion 13. As a result, mud and the like caught between the fin portions 13 are smoothly discharged. In this embodiment, the maximum width W2a of the fin portion 13 is the same as the width wb of the tip portion 13B.

The fin portion 13 includes, for example, an end-side fin portion 20 disposed on at least one of both ends 12e, 12e of the block body portion 12 in the tire axial direction. In this embodiment, a pair of end-side fin parts 20 are formed at both ends 12e, 12e of the block main body part 12. In this embodiment, the fin section 13 further includes a central fin section 21 provided at the central section 12c. Such a fin portion 13 greatly suppresses the collapse of the block main body portion 12.

In this embodiment, in the end-side fin portion 20, the width wb of the tip portion 13B is formed to be larger than the width wa of the root portion 13A. Since the end-side fin portion 20 supports both ends 12e, 12e of the block main body portion 12, which have relatively low rigidity, the traction performance and anti-skid performance are greatly improved over a long period of time.

FIG. 3 is a plan view of the finned block 11. As shown in FIG. 3, in this embodiment, the end fin portion 20 has a pair of edges (second longitudinal edges) 22 extending in the tire circumferential direction. The end fin portion 20 further includes, for example, a third horizontal edge 23 that connects the pair of second vertical edges 22 and extends in the tire axial direction. The tip portion 13B of the end-side fin portion 20 is formed to include the third lateral edge 23.

In the end-side fin portion 20, the pair of second longitudinal edges 22 include, for example, an outer edge 25 and an inner edge 26 disposed closer to the center portion 12c of the block body portion 12 in the tire axial direction than the outer edge 25. Contains.

In this embodiment, the outer edge 25 extends parallel to the tire circumferential direction. Such an outer edge 25 increases the scratching force in the axial direction of the tire, thereby increasing the anti-skid performance. For example, the outer edge 25 forms a straight line with the first longitudinal edge 17. This further improves the anti-skid performance over a long period of time. Note that the outer edge 25 is not limited to such a form.

For example, the inner edge 26 has a first inclined part 27 which is inclined toward the center part 12c of the block body part 12 in the tire axial direction toward the tip part 13B, and which is inclined in the opposite direction to the first inclined part 27. A second inclined portion 28 is included. Such an inner edge 26 is such that the first inclined part 27 exerts a shearing force on the mud etc. in the area surrounded by the first inclined part 27, the second inclined part 28, and the second lateral edge 16. , improve traction performance.

The first inclined portion 27 of this embodiment extends linearly. The first inclined portion 27 increases the shearing force. The first inclined portion 27 is continuous with the third lateral edge 23, for example.

The second inclined portion 28 of this embodiment extends in an arc shape. Such a second inclined portion 28 reduces the rigidity level difference at the connection portion between the block main body portion 12 and the fin portion 13, and increases the rigidity of the finned block 11. The second sloped portion 28 is, for example, smoothly connected to the second lateral edge 16 and the first sloped portion 27.

The angle θ1 of the inner edge 26 with respect to the tire circumferential direction is preferably 45 degrees or less, and more preferably 35 degrees or less. Such an inner edge 26 further increases the scratching force in the axial direction of the tire, thereby maintaining skid resistance performance over a long period of time. If the angle θ1 of the inner edge 26 is too small, the rigidity of the fin portion 13 cannot be increased, and the traction performance may not be improved. Therefore, the angle θ1 of the inner edge 26 is preferably 5 degrees or more, and more preferably 10 degrees or more. The angle θ1 of the inner edge 26 is measured at the first inclined portion 27 in this embodiment.

The shortest distance L3 in the tire axial direction between the inner edges 26, 26 of the pair of end-side fin portions 20 is preferably 0.15 to 0.75 times the width W1 of the block body portion 12 in the tire axial direction. . Since the shortest distance L3 is 0.15 times or more the width W1 of the block main body portion 12, smooth discharge of mud etc. caught between the pair of end side fin portions 20, 20 is maintained. Since the shortest distance L3 is 0.75 times or less than the width W1 of the block body 12, the maximum width W2a of the end fin portion 20 is maintained large, and the collapse of the block body 12 can be effectively suppressed. . In order to effectively exhibit the above-mentioned effect, in the finned block 11 of the present embodiment, the shortest distance L3 is more desirably 0.30 times or more the width W1 of the block body portion 12 in the tire axial direction, and more preferably 0.30 times or more. More preferably 40 times or more, and even more preferably 0.70 times or less.

FIG. 4 is an AA end view of FIG. 3. As shown in FIG. 4, in the end-side fin portion 20 of this embodiment, the block height h2 of the inner edge 26 is smaller than the block height h1 of the outer edge 25 at the tip portion 13B. Such an end-side fin portion 20 reduces the ground pressure acting on the inner edge 26, suppresses chipping and cracking of the tip portion 13B, and maintains a high scratching effect in the tire axial direction. If the block height h2 of the inner edge 26 is excessively smaller than the block height h1 of the outer edge 25, the scratching effect of the inner edge 26 may be reduced, and the anti-skid performance may deteriorate. From this point of view, the block height h2 of the inner edge 26 is preferably 80% or more and 90% or less of the block height h1 of the outer edge 25. In this specification, the block height is the height in the tire radial direction from the tread bottom surface 2S.

As shown in FIG. 3, the central fin portion 21 includes a pair of edges (third longitudinal edges) 30, 30 extending in the tire circumferential direction, and a third longitudinal edge extending in the tire axial direction connecting the third longitudinal edges 30, 30. 4 horizontal edges 31. In this embodiment, the fourth lateral edge 31 forms the tip portion 13B of the central fin portion 21.

In the present embodiment, the central fin portion 21 is formed so that the width wb of the tip portion 13B and the width wa of the root portion 13A are the same size. The central fin portion 21 includes, for example, a uniform width portion 32 whose width W2 in the tire axial direction is the same toward the tip portion 13B. In this embodiment, the equal width portion 32 extends parallel to the tire circumferential direction. Note that the central fin portion 21 is not limited to such a configuration, and for example, the width wb of the tip portion 13B may be formed larger than the width wa of the root portion 13A.

Although not particularly limited, it is desirable that the length L2b of the center fin portion 21 in the tire circumferential direction is larger than the length L2a of the end side fin portion 20 in the tire circumferential direction. Since such a central fin portion 21 has a large edge component in the tire axial direction, it improves sideslip resistance. If the length L2b of the central fin portion 21 becomes excessively large, chips or cracks will easily occur in the central fin portion 21, and the skid resistance performance will deteriorate on the contrary. Therefore, the length L2b of the central fin portion 21 is preferably 1.2 times or more, and more preferably 1.3 times or more, the length L2a of the end-side fin portions 20. Further, the length L2b of the central fin portion 21 is preferably 1.7 times or less, and more preferably 1.6 times or less, the length L2a of the end side fin portions 20.

FIG. 5 is a plan view of the tread portion 2. As shown in FIG. As shown in FIG. 5, the block 10 includes a crown block 10A, a pair of middle blocks 10B, and a pair of shoulder blocks 10C in this embodiment. The crown block 10A is arranged in a crown region Cr that includes the tire equator C, for example. The middle block 10B of this embodiment is arranged in a middle region Mi adjacent to the outer side of the crown region Cr in the tire axial direction. In this embodiment, the shoulder block 10C is arranged in a shoulder region Sh adjacent to the outer side of the middle region Mi in the tire axial direction. In this embodiment, the crown block 10A, middle block 10B, and shoulder block 10C are arranged in the tire circumferential direction.

The crown region Cr is a region that mainly touches the ground during straight running. In the crown region Cr of this embodiment, the length Wc in the tire axial direction centered on the tire equator C is 25% to 35% of the tread development width TW. The middle region Mi is a region where the vehicle primarily touches the ground at the beginning of a turn with a large turning radius. The length Wm of the middle region Mi in the tire axial direction in this embodiment is 15% to 25% of the tread development width TW. The shoulder region Sh is a region that primarily touches the ground at the end of a turn with a small turning radius. The length Ws of the shoulder region Sh in the tire axial direction in this embodiment is 5% to 15% of the tread development width TW.

In this embodiment, the crown block 10A and the middle block 10B are formed as a finned block 11. In this way, by using the finned blocks 11 as the crown block 10A and the middle block 10B, which have many chances of coming into contact with the ground, sideslip resistance and traction performance are further improved. Note that the present invention is not limited to such an embodiment; for example, only the crown block 10A may be formed as the finned block 11, or only the middle block 10B may be formed as the finned block 11.

The crown block 10A of this embodiment has a pair of end-side fin parts 20, 20 and a center fin part 21. The middle block 10B of this embodiment has only a pair of end side fin parts 20, 20, and is not provided with a center fin part 21. In addition, the crown block 10A may have only a pair of end side fin parts 20, 20, and may have a mode in which the center fin part 21 is not provided. Further, the middle block 10B may have a pair of end-side fin portions 20, 20 and a center fin portion 21 (not shown).

The end fin portion 20 of the middle block 10B has the same configuration as the end fin portion 20 of the crown block 10A. Therefore, in this specification, a different configuration from the end fin portion 20 of the crown block 10A will be explained regarding the end fin portion 20 of the middle block 10B.

In such a middle block 10B, the shortest distance L3b in the tire axial direction between the inner edges 26, 26 of the pair of end-side fin portions 20 is desirably 0.15 times or more the width W1 of the block body portion 12, and is 0. More preferably, it is 0.25 times or more, and even more preferably 0.35 times or more. Further, the shortest distance L3b is preferably 0.75 times or less, more preferably 0.65 times or less, and even more preferably 0.55 times or less than the width W1 of the block main body portion 12.

The block 10 includes, for example, at least two finned blocks 11 adjacent to each other in the tire axial direction. In this embodiment, the crown block 10A and the middle block 10B are adjacent to each other in the tire axial direction. It is desirable that the fin interval W4 between the crown block 10A and the middle block 10B is 50% or more of the block body interval W5. Thereby, mud and the like that tend to get caught between the crown block 10A and the middle block 10B can be smoothly discharged. Therefore, the scratching force in the tire axial direction by the outer edge 25 and the first longitudinal edge 17 of the crown block 10A and the outer edge 25 and the first longitudinal edge 17 of the middle block 10B is maintained, so the anti-skid performance is improved. It will be done. The fin part interval W4 is the shortest distance in the tire axial direction between the fin part 13 of the crown block 10A and the fin part 13 of the middle block 10B. The block body interval W5 is the shortest distance in the tire axial direction between the block body 12 of the crown block 10A and the block body 12 of the middle block 10B.

FIG. 6 is a plan view of the tread portion 2. FIG. As shown in FIG. 6, for example, the first lateral edge 15 of the middle block 10B is arranged on an imaginary line 15c extending the first lateral edge 15 of the crown block 10A outward in the tire axial direction. desirable. This further improves traction performance. The phrase "disposed on the imaginary line 15c" refers to a mode in which the imaginary line 15c and the first horizontal edge 15 of the middle block 10B completely match. Moreover, the above-mentioned "arranged on the imaginary line 15c" means that the first lateral edge is located within 20% of the length L1b of the block body portion 12 of the middle block 10B from the imaginary line 15c to both sides in the tire circumferential direction. 15 is arranged. In this embodiment, the virtual line 15c is formed as a straight line.

From a similar point of view, it is desirable that the third lateral edge 23 of the middle block 10B be arranged on an imaginary line 23c extending the third lateral edge 23 of the crown block 10A outward in the tire axial direction. The expression "disposed on the imaginary line 23c" refers to a state in which the imaginary line 23c and the third horizontal edge 23 of the middle block 10B completely match. Moreover, the above-mentioned "arranged on the imaginary line 23c" means that the first part of the middle block 10B is located within 20% of the length L2b of the fin portion 13 of the middle block 10B from the imaginary line 23c to both sides in the tire circumferential direction. This includes a mode in which three horizontal edges 23 are arranged. In this embodiment, the virtual line 23c is formed as a straight line.

In the tread portion 2 of this embodiment, a tie bar 35 is provided between the crown block 10A and the middle block 10B. Such tie bars 35 increase the rigidity of the end fin portions 20 of the crown block 10A and the end fin portions 20 of the middle block 10B, thereby improving traction performance and anti-skid performance. In this specification, the tie bar 35 is a convex body that connects adjacent blocks 10 and protrudes from the tread bottom surface 2S. The tie bar 35 has a height h4 smaller than the block height h3 of the block 10. The height h4 of the tie bar 35 is preferably 10% to 30% of the block height h3 of the block 10 (shown in FIG. 1).

In this embodiment, the tie bar 35 is formed over the entire area between the crown block 10A and the middle block 10B and between the imaginary line 15c and the imaginary line 23c. Thereby, the above-mentioned effect is exhibited more effectively.

When the rubber hardness of the block 10 is low, the block rigidity decreases and the block becomes easily deformed. Therefore, in order to achieve both the ability of the block 10 to penetrate into muddy ground and the prevention of the block 10 from falling down, it is preferable that the rubber hardness is 70 or higher. The upper limit of the rubber hardness is preferably 90 or less from the viewpoint of block chipping and the like. The rubber hardness is a durometer type A hardness measured in an environment of 23° C. using a durometer type A based on JIS-K6253.

FIG. 7 is a plan view showing another embodiment of the finned block 11. Constituent features that are the same as those of the finned block 11 of this embodiment may be given the same reference numerals and detailed descriptions thereof may be omitted. As shown in FIG. 7, in the finned block 11 of this embodiment, the outer edge 25 of the end-side fin portion 20 is inclined in the opposite direction to the inner edge 26 toward the tip portion 13B. Such outer edge 25 also helps to make the width wb of the tip portion 13B larger than the width wa of the root portion 13A, thereby improving traction performance and anti-skid performance over a long period of time. The outer edge 25 in this embodiment extends in a straight line. Such an end-side fin portion 20 is arranged, for example, on the crown block 10A or the middle block 10B.

The angle θ2 of the outer edge 25 with respect to the tire circumferential direction is preferably 45 degrees or less, and more preferably 35 degrees or less. Since such an outer edge 25 increases the scratching force in the tire axial direction, the anti-skid performance is maintained over a long period of time.

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

A motorcycle tire having the basic pattern shown in FIG. 5 was prototyped based on the specifications shown in Table 1. The traction performance and anti-skid performance of each test tire were then tested. The test methods and common specifications are as follows.

<Traction performance/anti-skid performance>
A test rider drove the following vehicle multiple times on an uneven road surface, and evaluated the stability of the vehicle due to traction when going straight and when turning, and the presence and size of skidding, etc. based on the test rider's sensibility. Evaluated. The running time is 30 minutes per run. The number of runs was three, and the test results of the first and third times are shown.
・Vehicle: For motocross competition with a displacement of 450cc ・Front tire (common use): Commercially available tire for rough terrain (tire size 80/100-21, rim size 1.60WM)
・Rear tire: Test tire shown in Table 1 (tire size 120/80-19, rim size 2.15WM)
・Internal pressure: 80kPa for both front and rear tires
・Block rubber hardness: 70

It can be confirmed that the tires of the examples have better traction performance and anti-skid performance than the tires of the comparative examples.

1 Two-wheeled vehicle tire 2 Tread portion 10 Block 11 Fin block 12 Block body portion 13 Fin portion 13A Root portion 13B Tip portion

Claims (10)

A motorcycle tire,
Multiple blocks are provided in the tread section,
The plurality of blocks include at least one finned block,
The finned block includes a block main body and at least one fin protruding from the block main body in the tire circumferential direction,
The fin portion includes a root portion connected to the block main body portion, and a tip portion opposite to the root portion,
The width of the tip portion in the tire axial direction is larger than the width of the root portion in the tire axial direction,
The fin portion includes an end-side fin portion disposed at at least one of both ends of the block body portion in the tire axial direction,
The end fin portion has a pair of edges extending in the tire circumferential direction,
The pair of edges include an outer edge and an inner edge disposed closer to the center of the block body in the tire axial direction than the outer edge,
The inner edge is inclined toward the center of the block main body in the tire axial direction toward the tip.
Motorcycle tires. The tread portion has a specified rotation direction,
The two-wheeled vehicle tire according to claim 1, wherein the fin portion protrudes from the block main body portion toward the rear arrival side in the rotational direction. The two-wheeled vehicle tire according to claim 1 or 2 , wherein the width of the fin portion in the tire axial direction increases continuously toward the tip end . The two-wheeled vehicle tire according to any one of claims 1 to 3 , wherein the angle of the inner edge with respect to the tire circumferential direction is 45 degrees or less . The two-wheeled vehicle tire according to any one of claims 1 to 4 , wherein the outer edge slopes in a direction opposite to the inner edge toward the tip end . The two-wheeled vehicle tire according to any one of claims 1 to 5 , wherein the angle of the outer edge with respect to the tire circumferential direction is 45 degrees or less . The two-wheeled vehicle tire according to any one of claims 1 to 6, wherein the fin portion includes a pair of end-side fin portions arranged at both ends of the block main body in the tire axial direction . According to claim 7, the shortest distance in the tire axial direction between the inner edges of the pair of end-side fin portions is 0.15 to 0.75 times the maximum width of the block body portion in the tire axial direction. motorcycle tires. The two-wheeled vehicle tire according to any one of claims 1 to 8 , wherein the end-side fin portion has a block height of the inner edge smaller than a block height of the outer edge at the tip portion . A motorcycle tire,
Multiple blocks are provided in the tread section,
The plurality of blocks include at least one finned block,
The finned block includes a block main body and at least one fin protruding from the block main body in the tire circumferential direction,
The fin portion includes a root portion connected to the block main body portion, and a tip portion opposite to the root portion,
The width of the tip portion in the tire axial direction is larger than the width of the root portion in the tire axial direction,
The block includes at least two of the finned blocks adjacent in the tire axial direction,
Between these finned blocks, the fin part interval is 50% or more of the block body part interval,
Motorcycle tires.

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