JP2022144967A - pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire with an excellent balance between traction performance and land rigidity.SOLUTION: A pneumatic tire comprises: shoulder major grooves 25 that divide a tread into a central region 22 in a tire axial direction and both adjacent shoulder lands 21 thereof; and a plurality of major grooves 26 and 27 that divide the central region 22 in the tire axial direction into a plurality of lands 23 and 24. Slits 30 and sipes 31 that divide the lands 23 and 24 by each extending in the tire axial direction are disposed on each of the lands 23 and 24 in the central region 22 in the tire axial direction, a slit bottom sipe 32 is disposed at the bottom of the slit 30, the depth of the slit 30 is 10 to 40% of the depth of the major grooves 26 and 27, and the sum of the depths of the slit 30 and the slit bottom sipe 32 is 60 to 90% of the depth of the major grooves 26 and 27.SELECTED DRAWING: Figure 1

Description

The present invention relates to pneumatic tires.

For example, as described in Patent Document 1, a shoulder main groove extending in the tire circumferential direction divides the tread into an axially central region of the tire and shoulder lands on both sides thereof, and another main groove divides the axially central region of the tire. Pneumatic tires that are divided into a plurality of land are known. A pneumatic tire is known in which slits and sipes extending in the tire axial direction are alternately provided in the tire circumferential direction, as described in Patent Document 1, in each land in the axial central region of such a pneumatic tire. ing.

Such a pneumatic tire has excellent traction due to the effect of the slits and sipes extending in the tire axial direction. In addition, not all grooves extending in the tire axial direction are slits, but slits and sipes narrower than the slits are provided alternately in the tire circumferential direction. is ensured.

JP 2015-116845 A

In the pneumatic tire described above, however, it is difficult to achieve a good balance between traction performance and land rigidity.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic tire that has an excellent balance between traction and rigidity on land.

In the pneumatic tire of the embodiment, the tread is divided into a plurality of lands extending in the tire circumferential direction by a plurality of main grooves extending in the tire circumferential direction. and a plurality of main grooves dividing the axial center region of the tire into a plurality of lands. In a pneumatic tire in which slits and sipes are provided to divide a land, and in each land the slits and the sipes are alternately provided in the tire circumferential direction, a sipe different from the sipe is provided at the bottom of the slit. A certain slit bottom sipe is provided, the depth of the slit is 10 to 40% of the depth of the main groove, and the depth of the groove that is the sum of the slit and the slit bottom sipe is the depth of the main groove. It is characterized by being 60 to 90%.

The pneumatic tire of the embodiment has an excellent balance between traction and land rigidity due to the above-described features of the slits and sipes.

The tread pattern of the pneumatic tire of the embodiment. AA sectional view of FIG. FIG. 2 is an enlarged view of part B of FIG. 1; CC sectional view of FIG.

Embodiments will be described based on the drawings. It should be noted that the embodiment described below is merely an example, and any suitable modifications within the scope of the present invention are included in the scope of the present invention.

The pneumatic tire of the embodiment has a general cross-sectional structure as a pneumatic tire except for the tread. Specifically, a bead portion (a bead portion is a portion including a bead core and a bead filler) is provided on both sides in the tire axial direction, and a carcass ply extends from one bead portion to the other bead portion in the axial direction of the tire. is provided. A belt is provided on the outer diameter side of the carcass ply, and a tread is provided on the outer diameter side of the belt. An inner liner is provided inside the carcass ply, and sidewall rubbers are provided on both sides of the carcass ply in the axial direction of the tire. In addition to the above, a plurality of rubber members are provided to configure the pneumatic tire.

As shown in FIG. 1, shoulder main grooves 25 extending in the tire circumferential direction are provided on both sides of the tread in the tire axial direction. The shoulder main grooves 25 divide the tread into a tire axial center region 22 where the tire equator C is located, and shoulder lands 21 on both sides in the tire axial direction.

The tire axial center region 22 includes a center main groove 26 overlapping the tire equator C and extending in the tire circumferential direction, and a quarter main groove 27 extending in the tire circumferential direction between the center main groove 26 and the shoulder main groove 25 . and are provided.

The center main groove 26, the quarter main groove 27, and the shoulder main groove 25 are zigzag-shaped main grooves. The width of zigzag axial deflection of the tire is larger in the order of the center main groove 26, the quarter main groove 27, and the shoulder main groove 25. Conversely, the shoulder main groove 25, the quarter main groove 27, and the center main groove 26 are nearly straight in that order.

Also, the center main groove 26 and the quarter main groove 27 of the tire axially central region 22 are narrower than the shoulder main grooves 25 . Specifically, the widths of the center main groove 26 and the quarter main groove 27 are 30 to 70% of the width of the shoulder main groove 25 .

By dividing the tire axial center region 22 into the center main groove 26 and the quarter main groove 27 , four lands extending in the tire circumferential direction are formed in the tire axial center region 22 . The four lands are the center land 23 between the center main groove 26 and the quarter main groove 27 and the quarter land 24 between the quarter main groove 27 and the shoulder main groove 25 .

Since the main grooves 25, 26, 27 are zigzag-shaped as described above, the center land 23, the quarter land 24, and the shoulder land 21 have wide width portions 23a, 24a, 21a and narrow width portions 23a, 24a, 21a. Parts 23b, 24b and 21b are formed.

Regarding the center land 23, in the wide width portion 23a, the main grooves on both sides of the center land 23 (the center main groove 26 and the quarter main groove 27) are bent in the direction of widening the width of the center land 23, and in the narrow width portion 23b. , the main grooves on both sides of the center land 23 are bent in the direction of narrowing the width of the center land 23 .

Regarding the quarter land 24, at the wide width portion 24a, the main grooves on both sides of the quarter land 24 (the quarter main groove 27 and the shoulder main groove 25) are bent in the direction of widening the width of the quarter land 24, and at the narrow width portion 24b. , the main grooves on both sides of the quarter land 24 are bent in the direction of narrowing the width of the quarter land 24 .

Regarding the shoulder land 21, at the wide width portion 21a, the shoulder main groove 25 bends in the direction of widening the width of the shoulder land 21, and at the narrow width portion 21b, the shoulder main groove 25 bends in the direction of narrowing the width of the shoulder land 21. is bent into

Slits 30 and sipes 31, which are a kind of grooves, are provided alternately in the tire circumferential direction on each land 23, 24 of the tire axially central region 22, respectively. That is, the slits 30 and the sipes 31 are alternately provided in each of the two center lands 23 in the tire circumferential direction, and the slits 30 and the sipes 31 are alternately provided in the two quarter lands 24 in the tire circumferential direction. Thereby, a plurality of blocks are formed in each of the center land 23 and the quarter land 24 . Here, the slits 30 and the sipes 31 are grooves that extend in the tire axial direction and divide the land. The slit 30 is a groove with a width greater than 1.5 mm. Sipe 31 is a groove with a width of 1.5 mm or less.

In the center land 23 , the slit 30 is provided in the narrow portion 23 b and connects the bent portion of the center main groove 26 and the bent portion of the quarter main groove 27 . In the center land 23 , the sipe 31 is provided in the wide portion 23 a and connects the bent portion of the center main groove 26 and the bent portion of the quarter main groove 27 .

Also in the quarter land 24 , the slit 30 is provided in the narrow portion 24 b and connects the bent portion of the center main groove 26 and the bent portion of the quarter main groove 27 . Also in the quarter land 24 , the sipe 31 is provided in the wide portion 24 a and connects the bent portion of the center main groove 26 and the bent portion of the quarter main groove 27 .

In the center land 23 and quarter land 24, the depth of the slit 30 is 10 to 40% of the depth of the center main groove 26 and quarter main groove 27. Further, as shown in FIG. 2 , in the center land 23 and the quarter land 24 , slit bottom sipes 32 having a width of 1.5 mm or less are provided at the groove bottom of the slit 30 . Further, in the center land 23 and the quarter land 24, the total depth of the slit 30 and the slit bottom sipe 32 is 60 to 90% of the depth of the center main groove 26 and the quarter main groove 27.

As shown in FIG. 1 , the slits 30 and the sipes 31 in the axially central region 22 of the tire are alternately aligned in the axial direction of the tire and aligned on one line. For example, next to the slit 30 of the quarter land 24 on one axial side of the tire is the sipe 31 of the center land 23 on one axial side of the tire, and next to the sipe 31 is the center land on the other axial side of the tire. There are 23 slits 30, and next to the slits 30, there is a sipe 31 of the quarter land 24 on the other axial side of the tire. And these slit 30, sipe 31, slit 30, and sipe 31 are located in a line on one line.

The slits 30 and the sipes 31 lined up on one line in this way extend in a direction inclined with respect to the tire axial direction so as to be symmetrical with respect to the tire equator C. As shown in FIG. That is, the slits 30 and sipes 31 on one side in the axial direction of the tire are arranged on a straight line that is inclined with respect to the axial direction of the tire, and the slits 30 and the sipes 31 on the other side in the axial direction of the tire are also inclined with respect to the axial direction of the tire. lined up in a straight line. The straight lines on one side and the other side in the tire axial direction are connected at the tire equator C and are line symmetrical with respect to the tire equator C. In FIG. 1, the bottom side is the side that touches the ground first when the tire rotates forward (when the tire rolls to move the vehicle forward). is V-shaped.

Notches 28 and 29 are formed at the ends of the sipe 31 facing the slit 30 across the main grooves 25 , 26 and 27 . More specifically, at places where the sipes 31 of the center land 23 open to the center main groove 26 and the quarter main groove 27 respectively, the center land 23 is cut to form triangular cutouts 28 . The notch 28 partially widens the width of the sipe 31 .

In addition, a notch 29 having a triangular shape is formed in the quarter land 24 at places where the sipes 31 of the quarter land 24 open to the quarter main groove 27 and the shoulder main groove 25, respectively. The notch 29 partially widens the width of the sipe 31 .

The shoulder land 21 is also provided with slits 33 and sipes 34 alternately in the tire circumferential direction. The slit 33 is a groove with a width greater than 1.5 mm. Sipe 34 is a groove with a width of 1.5 mm or less.

The slits 33 and sipes 34 of the shoulder land 21 are bent and extend in a V-shape when viewed with the side that touches the ground first when the tire rotates forward.

One end of the slit 33 of the shoulder land 21 (the end on the side of the tire equator C) opens into the shoulder main groove 25, and the other end is located beyond the ground contact edge E of the tire. Therefore, the slits 33 divide the shoulder land 21 into a plurality of blocks. A slit bottom sipe is not provided in the slit 33 of the shoulder land 21 .

One end of the sipe 34 of the shoulder land 21 (the end on the side of the tire equator C) opens into the shoulder main groove 25, and the other end is positioned closer to the tire equator C than the tire contact edge E. is blocked by That is, the other end of the sipe 34 is closed within the shoulder land 21 .

In the shoulder land 21 , the slit 33 is provided in the narrow portion 21 b and opens at the bent portion of the shoulder main groove 25 . Moreover, in the shoulder land 21 , the sipe 34 is provided in the wide portion 21 a and opens at the bent portion of the shoulder main groove 25 .

The opening end of the slit 33 of the shoulder land 21 to the shoulder main groove 25 faces the opening end of the sipe 31 of the quarter land 24 to the shoulder main groove 25 with the shoulder main groove 25 interposed therebetween. The opening end of the sipe 34 of the shoulder land 21 to the shoulder main groove 25 faces the opening end of the slit 30 of the quarter land 24 to the shoulder main groove 25 with the shoulder main groove 25 interposed therebetween.

A triangular notch 35 is formed in the shoulder land 21 at a location where the sipe 34 of the shoulder land 21 opens into the shoulder main groove 25 . The notch 35 partially widens the width of the sipe 34 .

As shown in FIGS. 3 and 4 , an inclined surface 36 is formed from the ground contact surface of the center land 23 to the bottom surface of the quarter main groove 27 at the notch 28 . Although not shown, all of the cutouts 28, 29, 35 are provided with inclined surfaces extending from the contact surface of the land to the bottom surface of the main groove as shown in FIGS.

A pneumatic tire having the above characteristics is attached, for example, to the drive side of a vehicle.

As described above, in the pneumatic tire of the present embodiment, the center land 23 and the quarter land 24 of the tire axially central region 22 are provided with the slits 30 and the sipes 31 that divide the lands 23 and 24, respectively. there is These slits 30 and sipes 31 make the pneumatic tire excellent in traction.

In addition, not all of the grooves provided in the center land 23 and the quarter land 24 are wide slits 30, but half of the grooves are narrow sipes 31. Therefore, when the lands 23 and 24 are deformed, the sipes 31 are not formed. It is easy to close and the rigidity of the lands 23 and 24 is ensured. Moreover, since the slits 30 and the sipes 31 are alternately arranged in the tire circumferential direction, the rigidity of the center land 23 and the quarter land 24 is made relatively uniform in the tire circumferential direction.

Moreover, since the depth of the slit 30 is 10% or more of the depth of the center main groove 26 and the quarter main groove 27, traction is ensured. Further, since the depth of the slit 30 is 40% or less of the depth of the center main groove 26 and the quarter main groove 27, the slit 30 is not too deep and the rigidity of the center land 23 and the quarter land 24 is ensured.

In addition, although the slit 30 is relatively shallow, since the slit bottom sipe 32 is provided at the bottom of the slit 30, the center land 23 and the quarter land 24 wear and the slit 30 becomes shallower or disappears. Also, traction is ensured by the slit bottom sipe 32 .

Further, since the depth of the grooves including the slits 30 and the slit bottom sipes 32 is 60% or more of the depths of the center main groove 26 and the quarter main groove 27, traction is ensured. In addition, since the depth of the groove obtained by adding the slit 30 and the slit bottom sipe 32 is 90% or less of the depth of the center main groove 26 and the quarter main groove 27, the rigidity of the center land 23 and the quarter land 24 is ensured. be.

As described above, the pneumatic tire of this embodiment has an excellent balance between the traction and the rigidity of the land 23, 24. FIG. Since the rigidity of the lands 23, 24 is ensured, the uneven wear resistance of the lands 23, 24 is improved, and the deformation of the lands 23, 24 is small, energy loss is reduced, and fuel efficiency is improved.

Such a pneumatic tire is particularly effective when mounted on the drive side of a vehicle because of its excellent traction.

Further, in this embodiment, the wide portions 23a, 24a, 21a of the lands 23, 24, 21 are provided with the sipes 31, 34, and the narrow portions 23b, 24b, 21b are provided with the slits 30, 33. The sipes 31,34 are longer than 30,33. Therefore, the lands 23, 24, 21 are more rigid.

Further, in this embodiment, the ends of the slits 30 and 33 and the ends of the sipes 31 and 34 face each other with the main grooves 25, 26 and 27 interposed therebetween, and the land 21, Notches 28, 29, 35 are provided by notching 23, 24. FIG. At the ends of the slits 30, 33 and the ends of the sipes 31, 34, the land 21, 23, 24 is formed with a small angle such as an acute angle. There are no corners for smaller angles to be made. Therefore, the rigidity of the corners of the lands 21, 23 and 24 can be ensured, and the occurrence of cracks due to large movements of the corners of the lands 21, 23 and 24 can be prevented.

Further, the wide portions 23a, 24a, 21a of the lands 23, 24, 21 are formed with corners of the lands 23, 24, 21 with a smaller angle than the narrow portions 23b, 24b, 21b. The notches 28, 29, 35 at the ends of the sipes 31, 34 in the wide portions 23a, 24a, 21a ensure the rigidity of the corners of the wide portions 23a, 24a, 21a.

Further, the tire axial center region 22 is subjected to a larger contact pressure than the shoulder land 21 . Therefore, by making the width of the center main groove 26 and the quarter main groove 27 narrower than the width of the shoulder main groove 25, specifically 70% or less, the rigidity of the tire axially central region 22 is ensured, resulting in a large ground contact pressure. The center land 23 and the quarter land 24 are less likely to deform even when a load is applied, ensuring low fuel consumption.

Moreover, since the width of the center main groove 26 and the quarter main groove 27 is 30% or more of the width of the shoulder main groove 25, side-slip resistance and drainage are ensured.

Further, in the tire axial center region 22, the slits 30 and the sipes 31 are aligned on one line on both sides of the tire equator C (that is, aligned on one line on both sides of the tire equator C). The lines on both sides of C are connected at the tire equator C), and extend in a V-shaped direction when viewed with the side that touches the ground first when the tire rotates forward. Therefore, resistance is less likely to occur when the tire rotates in the normal direction, resulting in good fuel efficiency.

In this embodiment, the center main groove 26, the quarter main groove 27, and the shoulder main groove 25 are zigzag-shaped main grooves. , the shoulder main groove 25 is the largest. Therefore, the main groove in the area where the ground contact pressure is greater has a larger zigzag shape, and when the tread touches the ground, the greater traction is exhibited.

Further, in the present embodiment, since the shoulder land 21 is also provided with the slit 33 and the sipe 34, the traction property is ensured. Here, since the slits 33 and the sipes 34 are alternately arranged in the tire circumferential direction, the rigidity of the shoulder land 21 is relatively uniform in the tire circumferential direction. Therefore, the shoulder land 21 is less likely to be unevenly worn.

In addition, although the shoulder land 21 is likely to receive a large lateral force, the sipe 34 of the shoulder land 21 is closed at the tire contact edge E side end inside the shoulder land 21, so the rigidity of the shoulder land 21 is ensured. ing. Therefore, the shoulder land 21 is less likely to be unevenly worn.

The slits 33 and sipes 34 of the shoulder land 21 are bent and extend in a V-shape when viewed with the side that touches the ground first when the tire rotates forward. Therefore, resistance is less likely to occur when the tire rotates in the normal direction, resulting in good fuel efficiency.

Various modifications can be made to the above embodiments.

For example, in the center land 23, the quarter land 24, and the shoulder land 21, the slits 30, 33 are provided in the wide width portions 23a, 24a, 21a, and the sipes 31, 34 are provided in the narrow width portions 23b, 24b. , 21b.

Also, in the center land 23, the quarter land 24 and the shoulder land 21, notches such as the notches 28, 29 and 35 of the above embodiment are located at the opening ends of the slits 30 and 33, not at the sipes 31 and 34. may be provided. In a preferred embodiment, notches are preferably formed in the wide parts 23a, 24a, 21a regardless of whether the wide parts 23a, 24a, 21a are provided with the slits 30, 33 or the sipes 31, 34. . However, notches may be formed in the narrow portions 23b, 24b, and 21b.

C... tire equator, E... tire ground contact edge, 21... shoulder land, 21a... wide width portion, 21b... narrow width portion, 22... tire axial center region, 23... center land, 23a... wide width portion, 23b... narrow width portion , 24...Quarter land, 24a...Wide width portion, 24b...Narrow width portion, 25...Shoulder main groove, 26...Center main groove, 27...Quarter main groove, 28...Notch, 29...Notch, 30...Slit, 31 ... Sipe 32 ... Slit bottom sipe 33 ... Slit 34 ... Sipe 35 ... Notch 36 ... Inclined surface

Claims (5)

The tread is divided into a plurality of lands extending in the tire circumferential direction by the plurality of circumferentially extending main grooves,
The main grooves include shoulder main grooves that divide the tread into a tire axial center region and shoulder lands on both sides thereof, and a plurality of main grooves that divide the tire axial center region into a plurality of lands,
A slit and a sipe extending in the tire axial direction and dividing the land are provided in each land of the axial center region of the tire,
In a pneumatic tire in which the slits and the sipes are alternately provided in the tire circumferential direction on each land,
A slit bottom sipe, which is a sipe different from the sipe, is provided at the bottom of the slit,
The depth of the slit is 10 to 40% of the depth of the main groove,
A pneumatic tire, wherein the depth of a groove obtained by adding said slit and said slit bottom sipe is 60 to 90% of the depth of said main groove. An end of the slit and an end of the sipe face each other across the main groove,
2. The pneumatic tire according to claim 1, wherein one of the two opposing ends is provided with a notch that cuts out the land. The pneumatic tire according to claim 1 or 2, wherein the width of the main groove in the tire axially central region is 30 to 70% of the width of the shoulder main groove. 2. The slit and the sipe are arranged on a single line on both sides of the tire equator and extend in a direction that forms a V shape when viewed with the side that touches the ground first when the tire rotates forward. 4. The pneumatic tire according to any one of 1 to 3. As the main grooves in the axially central region of the tire, a center main groove overlapping the tire equator and quarter main grooves on both sides of the center main groove are provided,
The center main groove, the quarter main groove and the shoulder main groove are zigzag main grooves,
The pneumatic tire according to any one of claims 1 to 4, wherein the width of zigzag axial deflection is larger in the order of the center main groove, the quarter main groove, and the shoulder main groove.

Images