阅读说明：本技术 重载用轮胎 (Heavy load tire ) 是由 长谷川朋生 于 2018-03-05 设计创作，主要内容包括：重载用轮胎(1)具备：周向槽(10),其沿着轮胎周向延伸；周向槽(12),其形成于比周向槽(10)靠轮胎宽度方向外侧的位置；多个横槽(11),其沿着轮胎宽度方向延伸；块(16),其由周向槽(10)、周向槽(12)以及多个横槽(11)划分形成；以及多个带束层(7)。周向槽(12)从轮胎赤道线侧朝向轮胎宽度方向外侧向与轮胎旋转方向相反的一侧倾斜地延伸。另外,周向槽(12)形成于比与构成带束层(7)的帘线和轮胎周向所成的角度最小的带束层的端部相对应的轮胎宽度方向位置靠轮胎宽度方向外侧的位置。(A heavy load tire (1) is provided with: a circumferential groove (10) extending in the tire circumferential direction; a circumferential groove (12) formed on the outer side of the circumferential groove (10) in the tire width direction; a plurality of lateral grooves (11) extending in the tire width direction; a block (16) which is formed by dividing a circumferential groove (10), a circumferential groove (12), and a plurality of transverse grooves (11); and a plurality of belt layers (7). The circumferential groove (12) extends obliquely from the tire equator line side to the outside in the tire width direction to the side opposite to the tire rotation direction. The circumferential groove (12) is formed on the outer side in the tire width direction than the position in the tire width direction corresponding to the end of the belt layer having the smallest angle formed by the cords constituting the belt layer (7) and the tire circumferential direction.)

1. A heavy duty tire characterized by comprising a tire body,

the heavy duty tire is provided with:

a 1 st circumferential groove extending in the tire circumferential direction;

a 2 nd circumferential groove formed on the outer side in the tire width direction than the 1 st circumferential groove;

a plurality of lateral grooves extending in the tire width direction;

a block partitioned by the 1 st circumferential groove, the 2 nd circumferential groove, and the plurality of lateral grooves; and

a plurality of belt layers, each of which is provided with a plurality of belt layers,

the 2 nd circumferential groove extends obliquely from the tire equator line side toward the tire width direction outer side to the side opposite to the tire rotation direction,

the 2 nd circumferential groove is formed on the outer side in the tire width direction than a tire width direction position corresponding to an end portion of a belt layer having a smallest angle formed by a cord constituting the belt layer and the tire circumferential direction.

2. The heavy-duty tire according to claim 1,

the 2 nd circumferential groove is curved from the tire equator line side toward the tire width direction outer side to the side opposite to the tire rotation direction.

3. The heavy duty tire according to claim 1 or 2,

at least one of the plurality of lateral grooves is inclined along the tire rotation direction from the tire equator line side toward the tire width direction outer side.

4. The heavy duty tire according to any one of claims 1 to 3,

the heavy duty tire further comprises a 1 st shoulder groove, the 1 st shoulder groove being open at a tread surface end and extending in the tire width direction,

the 2 nd circumferential groove is communicated with the 1 st shoulder groove.

5. The heavy-duty tire according to claim 4,

the 1 st shoulder groove communicates with at least 1 of the plurality of transverse grooves.

6. The heavy duty tire according to any one of claims 1 to 5,

the heavy duty tire further comprises a 2 nd shoulder groove communicating with one end and the other end of the 2 nd circumferential groove,

the 2 nd shoulder groove is inclined from the tire equator line side toward the tire width direction outer side to the side opposite to the tire rotation direction.

7. The heavy duty tire according to any one of claims 1 to 6,

in the case where the distance from one end to the other end of the tread surface end in the tire width direction is W, the distance from the tire equator line to one end of the 2 nd circumferential groove is L1, and the distance from the tire equator line to the other end of the 2 nd circumferential groove is L2,

l1 is 0.25W-0.4W,

l2 was longer than L1 and shorter than 0.4W.

8. The heavy duty tire according to any one of claims 1 to 7,

the belt layer with the smallest angle is a 1 st belt layer formed on the innermost side in the tire radial direction or a 2 nd belt layer formed on the outer side of the 1 st belt layer,

the 1 st belt layer or the 2 nd belt layer has a narrower width in the tire width direction than other belt layers.

Technical Field

The present invention relates to a heavy duty tire.

Background

In general, when a tire rolls, a force (driving force) in the tire rotation direction is generated in a region near the tire equator, and a force (braking force) in the opposite direction to the tire rotation direction is generated in a region near the ends in the tire width direction, so that a shearing force is generated near the boundary between the two regions. Due to the shear force, the block deforms when the tire rolls, the amount of wear decreases at the ground contact end, and the amount of wear increases at the kick-out end. That is, an eccentric wear occurs at the kicking-out end.

In order to suppress this uneven wear, for example, a tire described in patent document 1 is provided with a bottom raised portion in a part of a lug groove, and a narrow groove is provided between the tire and a land portion adjacent to the bottom raised portion. In the tire described in patent document 1, the height from the groove bottom to the surface of the raised portion is H1> H2 when the height of the tread on the kick-out end side is H1 and the height of the tread on the ground contact end side is H2. This improves the uneven wear resistance on the kick-out end side.

Disclosure of Invention

Problems to be solved by the invention

However, when a lateral force is applied to the block during cornering, the shear force increases due to the lateral force, and the kicking-out end side of the block is unevenly worn. However, patent document 1 does not consider this point.

The present invention has been made in view of the above problems, and an object thereof is to provide a heavy duty tire in which uneven wear resistance is improved by reducing a lateral force component of a shear force.

Means for solving the problems

The heavy duty tire according to claim 1 includes: a 1 st circumferential groove extending in the tire circumferential direction; a 2 nd circumferential groove formed further outward in the tire width direction than the 1 st circumferential groove; a plurality of lateral grooves extending in the tire width direction; the block is formed by dividing a 1 st circumferential groove, a 2 nd circumferential groove and a plurality of transverse grooves; and a plurality of belt layers. The 2 nd circumferential groove extends obliquely from the tire equator line side toward the tire width direction outer side to the side opposite to the tire rotation direction. Further, the 2 nd circumferential groove is formed at a position on the outer side in the tire width direction than a tire width direction position corresponding to an end portion of a belt layer where an angle formed by a cord constituting the belt layer and the tire circumferential direction is smallest.

In addition, in claim 1, the 2 nd circumferential groove is curved from the tire equator line side toward the tire width direction outer side to the side opposite to the tire rotation direction.

In addition, in claim 1, at least one of the plurality of lateral grooves is inclined along the tire rotation direction from the tire equator line side toward the tire width direction outer side.

In addition, according to claim 1, the heavy duty tire further includes a 1 st shoulder groove, the 1 st shoulder groove being open at the tread surface end and extending in the tire width direction. The 2 nd circumferential groove is communicated with the shoulder groove.

In addition, in claim 1, the 1 st shoulder groove communicates with at least 1 of the plurality of lateral grooves.

In addition, in claim 1, the heavy duty tire further includes a 2 nd shoulder groove communicating between one end portion and the other end portion of the 2 nd circumferential groove. The 2 nd shoulder groove is inclined from the tire equator line side toward the tire width direction outer side to the side opposite to the tire rotation direction.

In addition, in claim 1, when a distance from one end to the other end of the tread surface end in the tire width direction is W, a distance from the tire equator line to one end of the 2 nd circumferential groove is L1, and a distance from the tire equator line to the other end of the 2 nd circumferential groove is L2, L1 is 0.25W to 0.4W, and L2 is longer than L1 and shorter than 0.4W.

In addition, in claim 1, the belt layer having the smallest angle is the 1 st belt layer formed on the innermost side in the tire radial direction or the 2 nd belt layer formed on the outer side of the 1 st belt layer, and the 1 st belt layer or the 2 nd belt layer has a narrower width in the tire width direction than the other belt layers.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the eccentric wear resistance is improved by reducing the lateral force component of the shearing force.

Drawings

Fig. 1 is a cross-sectional view of a heavy duty tire according to an embodiment of the present invention in the tire radial direction in the tire width direction.

Fig. 2 is a diagram illustrating a belt structure of a heavy duty tire according to an embodiment of the present invention.

Fig. 3 is a plan view showing a tread of a heavy duty tire according to an embodiment of the present invention.

Fig. 4 (a) and 4 (b) are diagrams illustrating a difference between a case where no curved groove is present and a case where a curved groove is present.

Fig. 5 is a plan view showing a tread of a heavy duty tire according to an embodiment of the present invention.

Fig. 6 is a plan view showing a tread of a heavy duty tire according to an embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same reference numerals are given to the same portions, and the description thereof is omitted.

The structure of the heavy duty tire 1 according to the present embodiment will be described with reference to fig. 1. The heavy duty tire 1 of the present embodiment is suitable for heavy duty vehicles such as construction vehicles.

As shown in fig. 1, a heavy duty tire 1 includes: a pair of bead portions 2; a carcass layer 3 forming a skeleton of the heavy duty tire 1; and a tread portion 4 having a ground contact surface contacting a road surface.

The bead portion 2 has a bead core 5 and a bead filler 6. The carcass layer 3 extends in a ring shape between the bead cores 5.

At least two bead cores 5 are disposed so as to be separated in the tire width direction. The bead core 5 is formed by winding 1 bead wire 8 into an annular shape a plurality of times. The bead core 5 supports the cord tension of the carcass layer 3 generated by the internal pressure of the heavy duty tire 1. The bead wire 8 is coated with a rubber material.

The bead filler 6 is a rubber material for reinforcing the bead core 5, and is disposed in a space formed by folding back both side ends of the carcass layer 3 at the position of the bead core 5 toward the outer side in the tire width direction.

A belt layer 7 is formed between the carcass layer 3 and the tread portion 4. The belt layer 7 is formed by stacking a plurality of layers in the tire circumferential direction. As shown in fig. 1, the belt layer 7 has a protection belt layer 30, a main intersecting belt layer 31, and a small intersecting belt layer 32. The protection belt layer 30 has two protection belts 30A, 30B. The main cross belt layer 31 includes two main cross belts 31A and 31B. The small cross belt layer 32 has two small cross belts 32A, 32B.

As shown in fig. 1, the main cross belt layer 31 is disposed on the outer side of the small cross belt layer 32 in the tire radial direction, and the protection belt layer 30 is disposed on the outer side of the main cross belt layer 31 in the tire radial direction.

As shown in fig. 2, the angle β formed by the cords D constituting the small cross belt layer 32 and the tire circumferential direction is 4 ° to 10 °, and therefore, the small cross belt layer 32 is a large inclination belt, the angle formed by the cords constituting the main cross belt layer 31 and the tire circumferential direction is 18 ° to 35 °, the angle formed by the cords constituting the small cross belt layer 32 and the tire circumferential direction is 22 ° to 33 °, and the angle β formed by the cords constituting the small cross belt layer 32 and the tire circumferential direction is smallest compared with the angle of the main cross belt layer 31 and the angle of the protection belt layer 30.

Further, as shown in fig. 1, the lengths of the belt layers in the tire width direction have the following relationship. The small intersecting belt 32B is longer than the small intersecting belt 32A and shorter than the main intersecting belts 31A, 31B and the protection belts 30A, 30B. The small crossing belt 32A is the shortest among the 6 belt layers. The main intersecting belt 31B is longer than the small intersecting belts 32A, 32B, the main intersecting belt 31A, and the protection belt 30A, and is shorter than the protection belt 30B. The main intersecting belt 31A is longer than the small intersecting belts 32A, 32B, and shorter than the main intersecting belt 31B and the protection belts 30A, 30B. The protection belt 30B is longest among the 6 belt layers. The protection belt 30A is longer than the small intersecting belts 32A, 32B and the main intersecting belt 31A, and is shorter than the main intersecting belt 31B and the protection belt 30B. The ratio of the lengths is not particularly limited.

In fig. 1, circumferential grooves and the like to be discussed later are omitted, but the tread portion 4 is formed with each groove. In addition, the tread width W shown in fig. 1 is a distance between tread surface ends Te on both sides measured in the tire width direction on the developed view of the tread. In addition, the tread half width 1/2W shown in fig. 1 is a distance of half the tread width W. In addition, in the present invention, the tread half width 1/2W is described as the distance from the tire equator line CL to the tread end Te.

Next, the tread portion 4 will be described with reference to fig. 3. In fig. 3, arrow C indicates the tire rotation direction. The tire rotation direction is any direction in the tire circumferential direction, and is a direction in which the tire rotates when the vehicle is moving forward. Further, the tread quarter width 1/4W is a distance that is half of the tread half width 1/2W and is a distance measured from the tire equator line CL along the outer side in the tire width direction.

As shown in fig. 3, 1 circumferential groove 10 extending in the tire circumferential direction is formed in the tread portion 4. The circumferential groove 10 is formed on the tire equator line CL. The circumferential groove 10 is a linear groove. Further, a plurality of lateral grooves 11 (lateral grooves 11a, lateral grooves 11b) communicating with the circumferential groove 10 are formed. The lateral grooves 11a and 11b are formed adjacent to each other in the tire circumferential direction. The lateral grooves 11a and 11b are formed so as to curve in the tire rotation direction and extend in the tire width direction. The lateral grooves 11a and 11b are inclined from the tire equator line CL toward the outer side in the tire width direction along the tire rotation direction. The lateral grooves 11a and 11b have inflection points that change the orientation of the irregularities with respect to the tire circumferential direction from the tire equator line CL toward the outer side in the tire width direction. The lateral grooves 11a and 11b have a convex shape curved in the direction opposite to the tire rotation direction on the tire equator line CL side. The lateral grooves 11a and 11b have a convex shape curved in the tire rotation direction on the shoulder side. The shapes of the lateral grooves 11a and 11b are not limited to those of fig. 3. The lateral grooves 11a and 11b may extend linearly in the tire width direction. The shapes of the lateral grooves 11a and 11b may be different or the same as long as the kick-out end 15 has a large area as will be described later.

One end of the lateral groove 11a communicates with the circumferential groove 10, and the other end of the lateral groove 11a communicates with the 1 st shoulder groove 13. One end of the lateral groove 11b communicates with the circumferential groove 10, and the other end of the lateral groove 11b communicates with the circumferential groove 12. The circumferential groove 12 is formed so as to curve toward the tire width direction outer side from the tire equator line CL side to the opposite side to the tire rotation direction. In other words, the circumferential groove 12 is inclined from the tire equator line CL side toward the tire width direction outer side to the side opposite to the tire rotation direction. Further, the circumferential groove 12 has an inflection point that changes the orientation of the unevenness with respect to the tire width direction from the tire equator line CL side toward the tire width direction outer side. The circumferential groove 12 has a convex shape curved inward in the tire width direction on the tire equator line CL side. The circumferential groove 12 has a convex shape curved outward in the tire width direction on the shoulder side. In addition, the circumferential groove 12 is formed in plurality along the tire circumferential direction. One end 18 of the circumferential groove 12 communicates with the lateral groove 11b, and the other end 19 of the circumferential groove 12 terminates at the 1 st shoulder groove 13. Further, the circumferential groove 12 is curved in a region on the outer side in the tire width direction than the one end 18. In other words, the circumferential groove 12 is not curved in a region further toward the inner side in the tire width direction than the one end 18. Further, one end 18 of the circumferential groove 12 is formed at a position on the outer side in the tire width direction than the position in the tire width direction corresponding to the end of the belt layer having the smallest angle formed by the cord and the tire circumferential direction. In the present embodiment, the belt layers having the smallest angle formed by the cords with respect to the tire circumferential direction are the small cross belts 32A, 32B. Thus, the one end 18 of the circumferential groove 12 is formed at a position on the outer side in the tire width direction than the tire width direction position corresponding to the end of the small intersecting belts 32A, 32B. Further, it is preferable that the one end 18 of the circumferential groove 12 is formed at a position on the outer side in the tire width direction than the tire width direction position corresponding to the end of the small cross belt 32B.

As shown in fig. 3, the block 16 is defined by the circumferential groove 10, the lateral groove 11a, the lateral groove 11b, the circumferential groove 12, and the 1 st shoulder groove 13. Further, the blocks 16 are formed in plural along the tire circumferential direction, from the center region of the tread portion 4 to the shoulder region. The central region is the region from the tire equator line CL to the tread quarter width 1/4W. The shoulder region is a region located further outward in the tire width direction than the center region. The transverse groove 11a communicates with the 1 st shoulder groove 13, but is not limited thereto. The lateral groove 11a may communicate with the circumferential groove 12. In this case, the 1 st shoulder groove 13 may be shortened. As shown in fig. 3, a 1 st shoulder groove 13 and a 2 nd shoulder groove 14 are formed in the shoulder region of the tread portion 4. The 1 st shoulder groove 13 opens at the tread end Te and communicates with the lateral groove 11 a. The 2 nd shoulder groove 14 is formed so as to extend outward in the tire width direction from the tire equator line CL. In addition, the 2 nd shoulder groove 14 is inclined toward the side opposite to the tire rotation direction. Further, the 2 nd shoulder groove 14 may be a groove having no tire circumferential direction component. That is, the 2 nd shoulder groove 14 may be formed along the tire width direction and the horizontal direction.

As shown in fig. 3, the 2 nd shoulder groove 14 is formed between one end 18 and the other end 19 of the circumferential groove 12. The 2 nd shoulder groove 14 communicates with one end 18 and the other end 19 of the circumferential groove 12, terminating in a shoulder block 20. The 2 nd shoulder groove 14 is not opened at the tread end Te. By forming the 1 st shoulder groove 13 and the 2 nd shoulder groove 14, the rigidity of each block is improved. In fig. 3, the 2 nd shoulder groove 14 terminates in the shoulder block 20, but the present invention is not limited thereto. The 2 nd shoulder groove 14 may be opened at the tread surface end Te in the same manner as the 1 st shoulder groove 13. Further, as shown in fig. 3, the circumferential groove 12 communicates with both the 1 st shoulder groove 13 and the 2 nd shoulder groove 14.

Next, the operation and effect of the heavy duty tire 1 according to the present embodiment will be described. In general, when a tire rolls, a force (driving force) in the tire rotation direction is generated in a region near the tire equator, and a force (braking force) in the opposite direction to the tire rotation direction is generated in a region near the ends in the tire width direction, so that a shearing force is generated near the boundary between the two regions. Due to the shear force, the block deforms when the tire rolls, the amount of wear decreases at the ground contact end, and the amount of wear increases at the kick-out end. That is, a difference in wear occurs at both ends of the block in the tire circumferential direction, and the wear life of the tire becomes short.

In the present invention, the block 16 is defined by the circumferential groove 10, the lateral groove 11a, the lateral groove 11b, and the circumferential groove 12. The circumferential groove 12 is formed so as to curve toward the tire width direction outer side from the tire equator line CL side to the opposite side to the tire rotation direction. Thus, the kick-out end 15 having a large area is formed toward the outer side in the tire width direction in the vicinity of the boundary between the center region and the shoulder region. The lateral force is applied to the block 16 during cornering, and the shear force is increased by the lateral force, but the kick-out end 15 has a large area, and therefore the heavy duty tire 1 can disperse the shear force acting on the kick-out end 15. That is, as shown in fig. 4 (a) and (b), in the case where the curved groove (the circumferential groove 12) is present, the kick-out side 40 (the leading kick-out portion) has a larger area than the case where the curved groove is not present, and therefore, the heavy duty tire 1 can disperse the shearing force acting on the kick-out side 40. In this way, the heavy duty tire 1 can reduce the lateral force component of the shearing force, and can reduce the difference in wear between the ground contact end 17 and the kick-out end 15. This improves the uneven wear resistance of the heavy duty tire 1.

In the present embodiment, one end 18 of the circumferential groove 12 is formed on the outer side in the tire width direction than the position in the tire width direction corresponding to the end of the belt layer having the smallest angle between the cord and the tire circumferential direction. This improves the uneven wear resistance at the vicinity of the position from the tire equator line CL to the tread quarter width 1/4W.

In the present invention, the circumferential groove 12 is formed in a curved shape, but the push-out end 15 may have a large area, and the shape of the circumferential groove 12 is not limited to the curved shape. For example, as shown in fig. 5, the circumferential groove 12 may be a linear shape extending obliquely from the tire equator line CL side toward the tire width direction outer side toward the side opposite to the tire rotation direction. Here, since the circumferential groove 12 is formed to be curved, there is no acute angle, thereby improving the effect of reducing the lateral force component of the shear force. Therefore, it is preferable that the circumferential groove 12 is formed curved. Further, in the present invention, the kick-out end 15 having a large area is formed for one block 16.

As described above, when the tire rolls, a shear force is generated. When the tire is mounted on a shaft on which a braking force acts, the braking force is applied, whereby the shearing force becomes larger. In order to reduce such a shearing force, it is preferable to increase the above-mentioned driving force. Therefore, in the present embodiment, the lateral grooves 11a and the lateral grooves 11b are inclined from the tire equator line CL toward the tire rotation direction. Thereby, the driving force becomes large and the shearing force is reduced.

The distance L1 shown in fig. 6 is the distance from the tire equator line CL to the one end 18 of the circumferential groove 12. Further, the distance L2 is a distance from the tire equator line CL to the other end 19 (terminal end) of the circumferential groove 12. The distance L1 is preferably 0.25W to 0.4W, and the distance L2 is preferably longer than L1 and shorter than 0.4W. As shown in FIG. 6, the block 16 has regions of increasing area between the distances L1-L2. More specifically, the region having an increasing area is formed so as to increase gradually toward the outer side in the tire width direction as it advances toward the side opposite to the tire rotation direction. Accordingly, the kick-out end 15 has a large area, and thus the heavy duty tire 1 can disperse the shearing force acting on the kick-out end 15.

The entire contents of Japanese patent application No. 2017-122196 (application date: 2017, 6 and 22) are incorporated herein.

Description of the reference numerals

1. A heavy duty tire; 2. a bead portion; 3. a carcass layer; 4. a tread portion; 5. a bead core; 6. a bead filler; 7. a belt ply; 8. a bead wire; 10. a circumferential groove; 11. a transverse groove; 12. a circumferential groove; 13. the 1 st shoulder groove; 14. 2 nd shoulder groove; 15. kicking out the end; 16. a block; 17. a ground terminal; 20. a shoulder block; 30. a protective belt; 31. a main cross belt layer; 32. a small cross belt; te, tread end.