CN115107419A

CN115107419A - Pneumatic tire

Info

Publication number: CN115107419A
Application number: CN202210070044.6A
Authority: CN
Inventors: 中石彩纪
Original assignee: Toyo Tire Corp
Current assignee: Toyo Tire Corp
Priority date: 2021-03-18
Filing date: 2022-01-21
Publication date: 2022-09-27
Anticipated expiration: 2042-01-21
Also published as: CN115107419B; JP7170769B2; JP2022143838A

Abstract

The present invention provides a pneumatic tire, wherein each of a plurality of 1 st pattern blocks comprises: the tire tread has a circumferential slit which is open at both the 1 st block end and the 2 nd block end, a1 st circumferential sipe which is open at the 1 st block end and closed in the land portion, and a2 nd circumferential sipe which is open at the 2 nd block end and closed in the land portion. The plurality of axial slits each have: the first block end of the first block end is opened with the circumferential slit and the axial slit between the intersection point of the 1 st intersection portion, and the 2 nd block end of the second block end is opened with the circumferential slit and the axial slit between the intersection point of the 2 nd intersection portion. The 1 st intersection and the 2 nd intersection at the same axial slit are different in position from each other in the tire axial direction. The circumferential slit and the 2 nd circumferential sipe of the 1 st block adjacent to the 1 st side face each other with the axial slit therebetween, and the circumferential slit and the 1 st circumferential sipe of the 1 st block adjacent to the 2 nd side face each other with the axial slit therebetween.

Description

Pneumatic tire

Technical Field

The present invention relates to a pneumatic tire.

Background

Pneumatic tires, particularly heavy duty pneumatic tires mounted on trucks, buses and the like, are required to have uneven wear resistance as described in japanese patent application laid-open No. 2019-108122. In addition, a tire that can be mounted on a rear wheel as a driving wheel is required to have traction performance. A tire capable of being mounted on a front wheel as a steering wheel is required to have lateral sliding resistance.

Disclosure of Invention

The present invention provides a method for: a pneumatic tire capable of ensuring traction performance, uneven wear resistance, and lateral sliding resistance.

A pneumatic tire according to the present invention includes a land portion extending in a tire circumferential direction, the land portion including: a plurality of axial slits each opening at least any one of land ends on both sides in the tire axial direction, and a plurality of 1 st blocks arranged in the tire circumferential direction, the plurality of 1 st blocks each having: a1 st block end disposed on a1 st side in a tire circumferential direction, a2 nd block end disposed on a2 nd side opposite to the 1 st side in the tire circumferential direction, a circumferential slit extending in the tire circumferential direction and opened at both the 1 st block end and the 2 nd block end, a1 st circumferential sipe extending in the tire circumferential direction and opened at the 1 st block end and closed in the land portion, and a2 nd circumferential sipe extending in the tire circumferential direction and opened at the 2 nd block end and closed in the land portion, the plurality of axial slits each having: a1 st intersection portion which is an intersection point between the circumferential slit opened at the 1 st block end and the axial slit, and a2 nd intersection portion which is an intersection point between the circumferential slit opened at the 2 nd block end and the axial slit, the 1 st intersection portion and the 2 nd intersection portion being different in position in the tire axial direction at the same axial slit, the circumferential slit facing the 2 nd circumferential sipe of the 1 st block adjacent to the 1 st side across the axial slit, the circumferential slit facing the 1 st circumferential sipe of the 1 st block adjacent to the 2 nd side across the axial slit.

Drawings

Fig. 1 is a development view showing an example of a tread surface of a pneumatic tire of the present invention.

Fig. 2 is an enlarged expanded view showing a center land portion of embodiment 1.

Fig. 3 is an enlarged expanded view showing a center land portion of embodiment 1.

Fig. 4 is an enlarged expanded view showing a center land portion of embodiment 1.

Fig. 5 is a perspective view of the tread surface of embodiment 1 as viewed from obliquely above.

Fig. 6 is a cross-sectional view of each part shown in fig. 1 and 4.

Fig. 7 is a development view showing an example of a tread surface of a1 st modification example of embodiment 1.

Fig. 8 is a development view showing an example of a tread surface of modification 2 of embodiment 1.

Fig. 9 is a development view showing an example of a tread surface of modification 3 of embodiment 1.

Fig. 10 is a development view showing an example of a tread surface of the 4 th modification of embodiment 1.

Description of the reference numerals

1. 2 … center land portion (land portion); 4a, 4b … land end; 4c … block 1 end; 4d … block 2 end; 40 … axial slits; 40a … position 1; 40b … position 2; 40c … position 3; 41 … circumferential slits; 42 … circumferential sipe 1; 43 … circumferential sipe 2; 44 … intersection 1; 45 … intersection 2; AD … tire axial direction; AD3 … side 3; AD4 … side 4; b1 … block 1; b2 … block 2; CD … tire circumferential direction; side 1 of CD1 …; CD2 … side 2.

Detailed Description

[ embodiment 1 ]

Embodiment 1 of the present invention will be described below with reference to the drawings.

Fig. 1 is a developed view of a tread surface Tr provided in a pneumatic tire PT (hereinafter simply referred to as "tire PT") according to embodiment 1. Fig. 2 to 4 are partially enlarged views of the center land portion 1 shown in fig. 1. Fig. 5 is a perspective view of the tread surface of the pneumatic tire of embodiment 1 as viewed from obliquely above. FIG. 6 is a sectional view of the portion A1-A1 shown in FIG. 1, the portion A2-A2 shown in FIG. 4, the portion A3-A3 and the portion A4-A4. The vertical direction in fig. 1 to 5 corresponds to the tire circumferential direction CD, and the horizontal direction in fig. 1 to 5 corresponds to the tire axial direction AD. The figure shows the shape of the tread portion when the tire is new. As shown in fig. 1 and 5, the pneumatic tire PT includes: a plurality of

land portions

1, 2, 3 extending in the tire circumferential direction CD. The tire PT according to embodiment 1 is a heavy load tire mounted on a truck, a bus, or the like. Of course, the present invention is not limited to this, and the tire described in the present specification may be a tire for a small truck. However, it cannot be applied to a tire for a passenger car. In the case of JATMA, the term "minitruck tire" means: described in chapter "B: the tire for a small truck, the tire for heavy load, is: chapter C: "or" chapter D "for trucks and buses: tire for construction vehicles.

On a tread surface Tr (a ground contact surface with a road surface) of the tire PT, there are provided: and 3

main grooves

61, 62, 61 continuously extending in the tire circumferential direction CD. In embodiment 1, the number of main grooves is 3, but the present invention is not limited thereto. The number of the main grooves may be 3 or more. In embodiment 1, the present invention comprises: the shoulder main groove 61 located on the outermost side in the tire axial direction AD, and the center main groove 62 located on the inner side of the shoulder main groove 61 in the tire axial direction AD and closest to the tire equatorial plane TE. Further, although the main groove is not particularly limited, for example, the main groove may be configured such that: the groove width is 3% or more of the distance between the ground contact ends LE and LE (the dimension in the tire axial direction AD). Further, although the main groove is not particularly limited, for example, the main groove may be configured such that: has a groove width of 7.0mm or more. Further, although the main groove is not particularly limited, for example, the main groove may be configured such that: continuously in the tire circumferential direction CD, the groove depth thereof is deepest in the tread surface Tr, and a TWI (tread wear indicator) indicating the use limit of wear is provided in the groove thereof.

In the present specification, the slit means: a groove having a width narrower than the main groove but wider than the sipe. The slit includes: an axial slit 40 and a circumferential slit 41 described later. The sipe is represented by: the width of the groove is 1.5mm or less. The sipe includes: the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 described later.

The ground contact end LE is an outermost end of the tread surface Tr (ground contact surface) in the tire axial direction AD. The tread surface Tr (ground contact surface) means: the tire is mounted on a regular rim and filled with regular internal pressure, and is placed perpendicular to a flat road surface and is applied to a surface that comes into contact with the road surface when a regular load is applied. The regular rim is: in a specification system including a specification under which a tire is based, a rim is determined for each tire according to the specification. A "standard rim" if JATMA, and a "measuring rim" if TRA or ETRTO.

The normal internal pressure is: in a specification system including the specification to which the tire is subjected, the air pressure determined for each tire in accordance with each specification is the highest air pressure in case of JATMA, the maximum value described in the table "tire load limit under various cold inflation pressures" in case of TRA, and the "inflation pressure" in case of ETRTO.

The normal load is: in a specification system including specifications under which tires are based, loads are determined for each tire according to the respective specifications. The maximum load capacity is JATMA, the maximum value described in the above table is TRA, and the "load capacity" is ETRTO.

< shoulder land 3 >

As shown in fig. 1 and 5, the tire PT has, at both ends of the tread surface Tr in the tire axial direction AD: a shoulder land portion 3 extending in the tire circumferential direction CD. The shoulder land portion 3 is divided by the shoulder main groove 61 and the ground terminal LE. The shoulder land portions 3 extend continuously in the tire circumferential direction CD. The shoulder land portion 3 has: and a groove extending in the tire axial direction AD, opening between the shoulder main groove 61 and the ground contact end LE, and separating the shoulder land portion 3.

<

center land

1, 2 >

As shown in fig. 1 and 5, the tire PT has at least 1

center land portion

1, 2 between a pair of shoulder

main grooves

61, 61. The

central land portions

1, 2 are land portions closest to the tire equatorial plane TE. The

center land portions

1 and 2 of embodiment 1 are divided by a center main groove 62 and a shoulder main groove 61. The

center land portions

1, 2 extend in the tire circumferential direction CD, respectively. In embodiment 1, the center land portion 1 is disposed: and a3 rd side AD3 (left side in the figure) in the tire axial direction AD with respect to the tire equatorial plane TE. The center land portion 2 is disposed: the position on the 4 th side AD4 (right side in the figure) opposite to the 3 rd side AD3 in the tire axial direction AD is closer to the tire equatorial plane TE than the tire equatorial plane TE. Hereinafter, the center land portion 1 may be referred to as a1 st land portion, and the center land portion 2 may be referred to as a2 nd land portion. The center land portion 2 (2 nd land portion) has the same shape as the center 1 (1 st land portion), and the center land portion 2 is: the center land portion 1 is slid in the tire axial direction AD, and the positions of the land portions in the tire circumferential direction CD are made different. The center land portion 1 will be mainly described, and the center land portion 2 will not be described in detail.

< axial slit 40 >

As shown in fig. 1, 2, and 5, the center land portion 1 includes: a plurality of axial slits 40, and a plurality of 1 st blocks B1 (refer to fig. 2) arranged in the tire circumferential direction CD. The axial slits 40 may be opened to at least one of the land ends 4a and 4b on both sides in the tire axial direction AD. Accordingly, since the axial slit 40 is open to at least one of the

main grooves

61 and 62 on both sides, the traction performance can be ensured. The axial slits 40 in embodiment 1 are open at the land end 4a on the 3 rd side AD3 in the tire axial direction AD and at the land end 4b on the 4 th side AD4 in the tire axial direction AD, respectively. Accordingly, the plurality of axial slits 40 divide the center land portion 1 into a plurality of 1 st blocks B1 (refer to fig. 2). The axial slit 40 is shallower than either of the

main grooves

61, 62. This ensures the rigidity of the land portion of the center land portion 1, and thus ensures the wear resistance and the uneven wear resistance. Specifically, as shown in fig. 6, the depth D2 in the tire radial direction RD of the axial slit 40 is: the depth D1 of the

main grooves

61, 62 is 10% to 40%. The depth is a depth indicating the tire radial direction RD, but hereinafter, the tire radial direction RD is not described.

< 1 st block B1, 1

st block end

4c, 2 nd block end >

As shown in fig. 2, each of the plurality of 1 st blocks B1 of the center land portion 1 has: the 1 st block end 4c, the 2 nd block end 4d, a circumferential slit 41 extending in the tire circumferential direction CD, a1 st circumferential sipe 42 extending in the tire circumferential direction CD, and a2 nd circumferential sipe 43 extending in the tire circumferential direction CD. The 1 st block end 4c is disposed on the 1 st side CD1 in the tire circumferential direction of the 1 st block B1. The 2 nd block end 4d is disposed on the 2 nd side CD2 of the 1 st block B1 in the tire circumferential direction. The 2 nd side CD2 in the tire circumferential direction is opposite to the 1 st side CD1 in the tire circumferential direction. The 1 st block end 4c is formed by the axial slit 40. The 2 nd block end 4d is formed by the axial slit 40.

< circumferential slit 41 >

As shown in fig. 1, 2, and 5, the circumferential slit 41 is open at both ends of the 1 st block end 4c and the 2 nd block end 4 d. In embodiment 1, the circumferential slits 41 are formed in a straight line shape in a plan view (in a view parallel to the tire radial direction) while being inclined with respect to both the tire circumferential direction CD and the tire axial direction AD. The circumferential slit 41 is shallower than the

main grooves

61, 62. This ensures the rigidity of the land portion of the center land portion 1, and thus ensures the wear resistance and the uneven wear resistance. Specifically, as shown in fig. 6, the depth D2 of the circumferential slit 41 is: the depth D1 of the

main grooves

61, 62 is 10% or more and 40% or less. In embodiment 1, the depth D2 of the circumferential slits 41 is the same as the depth D2 of the axial slits 40, but the present invention is not limited thereto.

< 1

st intersection

44, 2 nd intersection 45 >

As shown in fig. 2 and 3, each of the plurality of axial slits 40 includes: the 1 st intersection portion 44 and the 2 nd intersection portion 45 are located at different positions in the tire axial direction AD. The 1 st intersection 44 is: the intersection between the opening of the circumferential slit 41 at the 1 st block end 4c and the axial slit 40. The 1 st intersection 44 is disposed: the 4 th side AD4 (right side in the figure) in the tire axial direction AD is positioned further than the 2 nd intersection 45. The 2 nd intersection 45 is: the intersection between the opening of the circumferential slit 41 at the 2 nd block end 4d facing the 1 st block end 4c and the axial slit 40. Accordingly, the openings of the circumferential slits 41 arranged on the 1 st side CD1 in the tire circumferential direction CD and the openings of the circumferential slits 41 arranged on the 2 nd side CD2 in the tire circumferential direction CD are arranged to be shifted from each other in the tire axial direction AD with the axial slits 40 interposed therebetween. The respective circumferential slits 41 are prevented from being continuously connected in the tire circumferential direction CD, so that the land portion rigidity can be improved.

< 1

st circumferential sipe

42, 2 nd circumferential sipe 43 >

As shown in fig. 1, 2, 3, and 5, the 1 st circumferential sipe 42 is open at the 1 st block end 4c and closed in the land portion. That is, the 1 st circumferential sipe 42 has one end opened to the 1 st block end 4c, but has the other end not opened to any of the axial slit 40, the circumferential slit 41, and the

main grooves

61 and 62. The 2 nd circumferential sipe 43 is open at the 2 nd block end 4d and closed in the land portion. That is, the 2 nd circumferential sipe 43 has one end opened to the 2 nd block end 4d, but has the other end not opened to any of the axial slit 40, the circumferential slit 41, and the

main grooves

61 and 62. In embodiment 1, the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 are linear in a plan view, but may have a wave shape. The 1 st circumferential sipe 42 is not connected to the 2 nd circumferential sipe 43. If the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 are linear in a plan view, the sipes are more easily opened than in the case of a waveform shape, and the lateral sliding resistance can be further improved. If the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 have a waveform shape in a plan view, movement of the land portion (the 1 st block B1) can be suppressed as compared with a case where the sipes are linear, and uneven wear resistance can be improved.

As shown in fig. 3, the length L42 of the 1 st circumferential sipe 42 in the tire circumferential direction CD is preferably: the length L41 of the circumferential slit 41 in the tire circumferential direction CD is 20% to 50%. The length L43 of the 2 nd circumferential sipe 43 in the tire circumferential direction CD is preferably: the length L41 of the circumferential slit 41 in the tire circumferential direction CD is 20% to 50%. This is because: the rigidity of the 1 st block B1 can be ensured, and the wear resistance and the partial wear resistance can be improved.

As shown in FIG. 6, the depth D3 of the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 is preferably: the depth D1 of the

main grooves

61, 62 is 10% to 50%. Accordingly, the block rigidity can be ensured, and the wear resistance and the uneven wear resistance can be improved. In embodiment 1, the depth D3 of the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 is the same as the depth D2 of the axial slit 40 and the circumferential slit 41, but the present invention is not limited thereto.

< positional relationship between circumferential sipes and circumferential slits >

As shown in fig. 3, the 1 st blocks B11, B12, B13 are aligned from the 1 st side CD1 toward the 2 nd side CD2 in the tire circumferential direction CD. The circumferential slit 41 of the 1 st block B12 and the 2 nd circumferential sipe 43 of the 1 st block B11 adjacent to the 1 st side CD1 face each other across the axial slit 40. Further, the circumferential slit 41 of the 1 st block B12 and the 1 st circumferential sipe 42 of the 1 st block B13 adjacent to the 2 nd side CD2 face each other across the axial slit 40.

Here, the so-called "facing" may be: the extension V1 of the center line of the

circumferential sipes

42, 43 enters the axial slit 40. In addition, the so-called "facing" may be: when an imaginary line V2 passing through the open ends of the

circumferential sipes

42 and 43 and the axial slit 40 and being parallel to the tire circumferential direction CD is drawn, the opening of the

circumferential sipe

42 or 43 and the opening of the axial slit 40 at least partially overlap each other.

As shown in fig. 2, in the 1 st embodiment, among the 1 st blocks B1, the 1 st circumferential sipe 42 is disposed on the 3 rd side AD3 (left side in the drawing) in the tire axial direction AD of the circumferential slit 41, and the 2 nd circumferential sipe 43 is disposed on the 4 th side AD4 (right side in the drawing) in the tire axial direction AD of the circumferential slit 41. Among the 1 st blocks B1, the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 are disposed: the positions of the circumferential slits 41 are sandwiched from both sides in the tire axial direction AD. Accordingly, the rigidity balance in the 1 st block B1 is good, and the partial wear resistance is improved.

As shown in fig. 2, the axial slits 40 are inclined with respect to both the tire axial direction AD and the tire circumferential direction CD. The axial slit 40 is curved at the 1 st intersection 44 and the 2 nd intersection 45, and has 2 curved points (the 1 st intersection 44 and the 2 nd intersection 45). The axial slit 40 is formed in a straight line at a portion between the bending points and a portion from the bending point to the land end. Accordingly, the axial slit 40 has: 3 linear portions and 2 bending points (44, 45) connecting the adjacent 2 linear portions. By providing the axial slits 40 with the bending points in this way, the axial slits 40 can be made to have a component extending in the tire circumferential direction CD, and lateral sliding resistance can be ensured. On the other hand, although the 1 st block B1 is easily moved by the axial slit 40, by providing the bending point, excessive movement of the 1 st block B1 can be suppressed. As a result, the uneven wear resistance can be improved.

As shown in fig. 2, at the 1 st intersection 44, which is a bending point of the axial slit 40, the 2 nd circumferential sipe 43 opens in the axial slit 40, and the circumferential slit 41 opens in the axial slit 40. Further, at the 2 nd intersection 45 which is a bending point of the axial slit 40, the 1 st circumferential sipe 42 is opened in the axial slit 40, and the circumferential slit 41 is opened in the axial slit 40. Accordingly, the circumferential slits 41 and the

circumferential sipes

42 and 43 are opened at the bending points of the axial slits 40, whereby the circumferential slits 41 and the

circumferential sipes

42 and 43 can be effectively opened, and the traction performance and the lateral sliding resistance can be improved.

As shown in fig. 3, the 1 st block end 4c is open at the 2 nd intersection 45 of the convex shape (mountain) in the plan view, and the 1 st circumferential sipe 42 is open at the axial slit 40. Accordingly, an acute angle θ 1 is easily generated at any one of the corner portions (1 st corner portion) of the 2 land portions formed between the 1 st circumferential sipe 42 and the axial slit 40. On the other hand, at the 2 nd intersection 45 where the 2 nd block end 4d assumes a concave shape (valley) in plan view, the circumferential slit 41 facing the 1 st circumferential sipe 42 opens in the axial slit 40. Accordingly, the obtuse angle θ 2 is easily generated at any one of the corner portions (2 nd corner portions) of the 2 land portions formed between the circumferential slit 41 and the axial slit 40. Although uneven wear is likely to occur at the 1 st corner and the 2 nd corner, since the land portion formed by the circumferential slit 41 having a larger width than the

circumferential sipes

42 and 43 is likely to move, the 2 nd corner is likely to be unevenly worn as compared to the 1 st corner. Accordingly, compared to the configuration (fig. 8) in which the circumferential slit 41 is open in the axial slit 40 at the intersection portion where the block end has the convex shape, the configuration in which the circumferential slit 41 is open in the axial slit at the intersection portion where the block end has the concave shape is likely to be an obtuse angle due to the corner portion between the circumferential slit 41 and the axial slit 40, and therefore, the uneven wear resistance can be improved.

The 1 st intersection 44 may be the same as described above. Specifically, the 2 nd block end 4d is formed at the 1 st intersecting portion 44 having a convex shape in a plan view, and the 2 nd circumferential sipe 43 is opened in the axial slit 40. The 1 st block end 4c presents a1 st intersection 44 of a concave shape in a plan view, and the circumferential slit 41 facing the 2 nd circumferential sipe 43 opens in the axial slit 40. In addition, the sum of the angles of the 2 nd corners may be greater than: the sum of the angles of 2 1 st corner portions facing the 2 nd corner portions.

< relationship between center land portion 1 (1 st land portion) and center land portion 2 (2 nd land portion) >

As shown in fig. 1, the center land portion 1 (1 st land portion) and the center land portion 2 (2 nd land portion) are different in position in the tire circumferential direction CD. Specifically, the axial slits 40 of the 2 nd land portion (2) and the axial slits 40 of the 1 st land portion (1) do not overlap each other when viewed along the tire axial direction AD (when viewed from a line of sight parallel to the tire axial direction AD). That is, when the axial slits 40 of the 2 nd land portion (2) and the axial slits 40 of the 1 st land portion (1) are projected in parallel to the tire axial direction AD on the tire equatorial plane TE as a projection plane, the axial slits 40 of the 2 nd land portion (2) and the axial slits 40 of the 1 st land portion (1) do not overlap each other.

Further, the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 of the 1 st land portion (1) and the axial slit 40 of the 2 nd land portion (2) do not overlap each other when viewed in the tire axial direction AD.

Accordingly, since the traction elements (the 1 st circumferential sipe 42, the 2 nd circumferential sipe 43, and the axial slits 40) are dispersedly present in a range in contact with the road surface, the traction performance and the lateral sliding resistance performance can be exhibited when the tire rotates.

< bottom knife groove pattern 46 >

As shown in fig. 4 to 6, each of the circumferential slits 41 and the axial slits 40 includes: a portion of the bottom surface of the slot is in the form of an open undercut pattern 46. In fig. 4, the bed knife pattern 46 is shown in hatched lines. Accordingly, compared to the configuration in which only the

slits

40 and 41 are formed, the block rigidity can be ensured by the bottom sipe 46, and the traction performance and the lateral sliding resistance performance in the middle stage of wear can be improved. As shown in fig. 6, the maximum depth D4 obtained by adding the

slits

40, 41 and the bed knife groove pattern 46 is preferably: the depth D1 of the

main grooves

61, 62 is 40% to 90%. Accordingly, the traction performance and the lateral sliding resistance in the middle stage of wear can be improved. As shown in fig. 5, the bed knife groove pattern 46 of the circumferential slit 41 is: the shape is not limited to a shape in which the shallowest shallow bottom portion 46a is provided at the center in the sipe length direction and the deepest deep bottom portions 46b are provided at both sides of the shallow bottom portion 46a in the sipe length direction. The depth of the undercut groove pattern 46 of the axial slit 40 is constant except at the ends.

As shown in fig. 4 and 5, each of the plurality of axial slits 40 includes: a1 st region 40a from the land end 4b of the 4 th side AD4 (right side in the figure) to the 1 st intersection 44, a2 nd region 40b from the 1 st intersection 44 to the 2 nd intersection 45, and a3 rd region 40c from the 2 nd intersection 45 to the land end 4a of the 3 rd side AD3 (left side in the figure). The bed grooving pattern 46 is formed in the 1 st portion 40a and the 3 rd portion 40 c. On the other hand, the bed sipe 46 is not formed in the No. 2 portion 40 b. The 1 st and 3

rd portions

40a, 40c and the circumferential slits 41 having the undercut 46 are arranged such that: in a zigzag shape in plan view. Accordingly, by not forming the undercut groove pattern 46 in the 2 nd portion 40b, which is the center portion of the center land portion 1 in the tire axial direction AD, the land portion rigidity can be improved, and the wear resistance and the uneven wear resistance can be improved. Further, by arranging the bed grooving pattern 46 in a zigzag shape, the traction performance and the lateral sliding resistance performance by the bed grooving pattern 46 can be ensured. Further, the 2 1 st blocks B11, B12 partitioned by the axial slit 40 are connected in the tire circumferential direction CD at the 2 nd site 40B to form the 2 nd block B2 which is a virtual joint of the 1 st blocks B11, B12, and therefore the blocks become longer in the tire circumferential direction CD virtually, and the tire circumferential direction rigidity (front-rear rigidity) of the center land portion 1 can be ensured, and the partial wear resistance can be improved.

The bed sipe 46 disposed in the 1 st portion 40a or the 3 rd portion 40c of the axial slit 40 is formed by: one end is open in the

main trench

61 or 62 and the other end is closed in the land portion. The bed sipe 46 arranged in the circumferential slit 41 is closed in the land portion.

The length of the bed groove pattern 46 formed in the circumferential slit 41 in the tire circumferential direction CD is preferably: the length L41 of the circumferential slit 41 in the tire circumferential direction CD is 80% to 100%.

The total length of the undercut groove pattern 46 formed in the axial slit 40 in the tire axial direction AD is preferably: the axial slits 40 are 50% to 70% of the length in the tire axial direction AD. The length in the tire axial direction AD of the bed sipe 46 formed in the 1 st portion 40a is preferably: the 1 st portion 40a has a length in the tire axial direction AD of 70% to 90%. The length in the tire axial direction AD of the bed sipe 46 formed in the 3 rd portion 40c is preferably: the 3 rd portion 40c is 70% to 90% of the length in the tire axial direction AD.

As shown in fig. 4, the center land portion 1 has: a plurality of 1-th blocks B1(B11, B12) divided in the tire circumferential direction CD by the axial slits 40, and a plurality of 2-th blocks B2 divided in the tire circumferential direction CD by the 1 st portion, the 3 rd portion having the bottom sipe, and the circumferential slits 41. The length LB2 in the tire circumferential direction CD of the 2 nd block B2 is longer than: the length LB1 in the tire circumferential direction CD of the 1 st block B1. This ensures tire circumferential rigidity (front-rear rigidity) of the center land portion 1, and improves uneven wear resistance.

[ modified examples ]

(1) Fig. 7 shows a tread surface of a1 st modification of embodiment 1. As shown in fig. 7, the axial slit 40 may be linear in a plan view, and may not be bent without having a bent portion. In embodiment 1 shown in fig. 1 to 6, the axial slits 40 include: 3 linear portions and 2 curved points, the linear portions being connected at the curved points, but the linear portions may be curved. In modification 1 of fig. 7, the arrangement of the pattern of bed notches 46 is the same as that of embodiment 1 shown in fig. 1 to 6.

(2) In embodiment 1 shown in fig. 3, the axial slits 40 are curved at the

intersections

44, 45, and the circumferential slits 41 open to the axial slits 40 at the

intersections

44, 45 that have a concave shape (valley) in plan view. For example, as shown in fig. 8. Fig. 8 shows a tread surface of a2 nd modification of embodiment 1. As shown in fig. 8, the

circumferential sipes

42 and 43 may be opened in the axial slit 40 at the

intersections

44 and 45 that exhibit the convex shape (mountain) in plan view, and opened in the axial slit 40 at the

intersections

44 and 45 that exhibit the concave shape (valley) in plan view. With such a configuration, the circumferential slits 41 and the

circumferential sipes

42 and 43 are opened at the curved points of the axial slits 40, so that the circumferential slits 41 and the

circumferential sipes

42 and 43 can be effectively opened, and the traction performance and the lateral sliding resistance can be improved. However, as shown in fig. 8, the angles of the corners of the 2 land portions formed between the circumferential slits 41 and the axial slits 40 are often acute angles θ 1, and the uneven wear resistance performance is slightly lower than that of the configuration shown in fig. 3.

In the 2 nd modification of fig. 8, the arrangement of the pattern of the bed sipes 46 is not shown, but is the same as that of the 1 st embodiment shown in fig. 1 to 6.

(3) In embodiment 1 shown in fig. 1 to 5, the plurality of axial slits 40 are open at both of the land ends 4a and 4b on both sides in the tire axial direction AD, but the present invention is not limited thereto. For example, as shown in fig. 9. Fig. 9 shows a tread surface of a modification 3 of embodiment 1. As shown in fig. 9, each of the plurality of axial slits 40 is open only at one land end of the land ends 4a and 4b on both sides in the tire axial direction AD. In the example shown in fig. 9, the axial slit 40 includes: a1 st axial slit which is open at a land end 4a of a3 rd side AD3 in the tire axial direction AD and closed in the land portion by being separated from a land end 4b of a4 th side AD4, and a2 nd axial slit which is open at a land end 4b of a4 th side AD4 and closed in the land portion by being separated from a land end 4a of a3 rd side AD 3. As shown in fig. 9, the 1 st axial slits and the 2 nd axial slits are alternately arranged along the tire circumferential direction CD. In this case, the length of the axial slit 40 in the tire axial direction is preferably: the center land portion 1 (land portion) has a length of 60% or more in the tire axial direction AD. Accordingly, the plurality of axial slits 40 divide the land portion into a plurality of virtual 1 st blocks B1 in the tire circumferential direction CD.

(4) In embodiment 1, the circumferential slits 41 are inclined with respect to both the tire circumferential direction CD and the tire axial direction AD, but the present invention is not limited thereto. For example, as shown in fig. 10, the circumferential slit 41 may be parallel to the tire circumferential direction CD. Fig. 10 shows a tread surface of a4 th modification of embodiment 1.

In addition, in embodiment 1, the circumferential slits 41 are sandwiched from both sides in the tire axial direction AD by the 1 st circumferential sipes 42 and the 2 nd circumferential sipes 43 in each of the 1 st blocks, but the present invention is not limited to this. For example, as shown in fig. 10, in each of the 1 st blocks, the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 may be disposed only in one of the tire axial directions AD of the circumferential slit 41.

(5) In embodiment 1, a plurality of (2)

central land portions

1 and 2 are provided with the tire equatorial plane TE therebetween, but 1 central land portion may be provided.

(6) The tire PT of the embodiment shown in fig. 1 to 10 includes: a tread pattern which is point-symmetric to the left and right about a point on the tire equatorial plane TE. However, it is not limited thereto. For example, the tire PT may have: a tread pattern that is line-symmetric about the tire equatorial plane TE, a tread pattern that is asymmetric about the tire, or a directional tread pattern that specifies the tire rotational direction.

As described above, as in embodiment 1 shown in fig. 1 to 6 and the modified examples shown in fig. 7 to 10, the pneumatic tire PT may include: land portions 1, 2 extending in the tire circumferential direction CD, the land portions 1, 2 having: a plurality of axial slits 40 and a plurality of 1 st blocks B1 arranged in the tire circumferential direction CD, the plurality of axial slits 40 each opening at least one of the land ends 4a, 4B on both sides in the tire axial direction AD, the plurality of 1 st blocks B1 each having: a1 st block end 4c disposed at a1 st side CD1 in the tire circumferential direction CD, a2 nd block end 4d disposed at a2 nd side CD2 opposite to the 1 st side CD1 in the tire circumferential direction CD, a circumferential slit 41 extending in the tire circumferential direction CD and opening at both the 1 st block end 4c and the 2 nd block end 4d, a1 st circumferential sipe 42 extending in the tire circumferential direction CD and opening at the 1 st block end 4c and closing in the land portion, and a2 nd circumferential sipe 43 extending in the tire circumferential direction CD and opening at the 2 nd block end 4d and closing in the land portion, the plurality of axial slits 40 each having: the 1 st intersecting portion 44, which is the intersection between the circumferential slit 41 opened at the 1 st block end 4c and the axial slit 40, and the 2 nd intersecting portion 45, which is the intersection between the circumferential slit 41 opened at the 2 nd block end 4d and the axial slit 40, are different from each other in the tire axial direction AD position in the 1 st intersecting portion 44 and the 2 nd intersecting portion 45 at the same axial slit 40, the circumferential slit 41 and the 2 nd circumferential sipe 43 of the 1 st block adjacent to the 1 st side CD1 face each other across the axial slit 40, and the circumferential slit 41 and the 1 st circumferential sipe 42 of the 1 st block adjacent to the 2 nd side CD2 face each other across the axial slit 40.

According to this configuration, the traction performance can be ensured by the axial slits 40 opened to the land ends, and the lateral sliding resistance against the lateral force in the tire axial direction AD can be improved by the circumferential slits 41 and the

circumferential sipes

42 and 43 extending in the tire circumferential direction CD. Further, the circumferential slits 41 and the

circumferential sipes

42 and 43 are alternately arranged along the tire circumferential direction over the plurality of 1 st blocks B1, and the opening positions of the circumferential slits 41 are different, whereby the circumferential slits 41 are prevented from being continuously connected in the tire circumferential direction CD, and therefore, the rigidity balance of the blocks can be ensured, and the uneven wear resistance can be improved.

As in the embodiments shown in fig. 1 to 9, the following configuration may be adopted: in each of the 1 st blocks B1, the 1 st circumferential sipe 42 is disposed on the 3 rd side AD3 in the tire axial direction AD of the circumferential slit 41, and the 2 nd circumferential sipe 43 is disposed on the 4 th side AD4 opposite to the 3 rd side AD3 in the tire axial direction AD of the circumferential slit 41.

According to this configuration, the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 are arranged: since the circumferential slits 41 are positioned on both sides in the tire axial direction AD, the rigidity balance in one block is improved, and the uneven wear resistance can be further improved.

As in the embodiment shown in fig. 1 to 10, the lengths L42, L43 in the tire circumferential direction CD of the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 may be 20% or more and 50% or less of the length in the tire circumferential direction CD of the circumferential slit 41.

According to this configuration, the block rigidity can be ensured, and the wear resistance and the uneven wear resistance can be improved.

As in the embodiment shown in fig. 1 to 10, the circumferential slits 41 and the axial slits 40 may each have: a portion of the slit floor is provided with an open undercut pattern 46.

According to this configuration, the block rigidity can be ensured, and the traction performance and the lateral sliding resistance in the middle stage of wear can be improved.

As in the embodiments shown in fig. 1 to 8, the following configuration may be adopted: the plurality of axial slits 40 open to both land ends 4a, 4b of a3 rd side AD3 land end 4a in the tire axial direction AD and a4 th side AD4 land end 4b opposite to the 3 rd side AD3 land end 4b in the tire axial direction AD, the 1 st intersecting part 44 is disposed at a position closer to the 4 th side AD4 than the 2 nd intersecting part 45 in each of the plurality of axial slits 40, and each of the plurality of axial slits 40 has: the pattern 46 of the undercut is formed in the 1 st portion 40a and the 3 rd portion 40c, and is not formed in the 2 nd portion 40b, from the land end 4b of the 4 th side AD4 to the 1 st intersection 44, the 2 nd portion 40b from the 1 st intersection 44 to the 2 nd intersection 45, and the 3 rd portion 40c from the 2 nd intersection 45 to the land end 4a of the 3 rd side AD 3.

According to this configuration, the 2 nd site 40b is the tire axial direction center portion of the land portion, and the rigidity of this portion can be improved, so that the wear resistance and the uneven wear resistance can be improved. Further, the 1 st and 3

rd portions

40a and 40c and the circumferential slit 41 having the undercut 46 are arranged such that: the zigzag pattern in plan view can retain the traction element and the lateral sliding resistance by the

circumferential sipes

42 and 43, and the 1 st block B1 partitioned by the axial slit 40 is connected in the tire circumferential direction CD by the 2 nd portion 40B, and the 1 st block B1 is lengthened in the tire circumferential direction CD, so that the front-rear rigidity of the land portion (rigidity in the tire circumferential direction CD) can be ensured, and the uneven wear resistance can be improved.

As in the embodiment shown in fig. 4, the following configuration may be adopted: the land portion 1 has a plurality of 2 nd blocks B2, the plurality of 1 st blocks B1 are each divided in the tire circumferential direction CD by an axial slit 40, the plurality of 2 nd blocks B2 are each divided in the tire circumferential direction CD by a1 st portion 40a, a3 rd portion 40c having a bottom-knife groove pattern 46, and a circumferential slit 41, and a length LB2 in the tire circumferential direction CD of the 2 nd block B2 is longer than: the length in the tire circumferential direction CD of the 1 st block B1.

According to this configuration, the front-rear rigidity of the land portion (the rigidity in the tire circumferential direction CD) can be ensured, and the uneven wear resistance can be further improved.

As in the embodiments shown in fig. 1 to 6 and 8 to 10, the following configuration may be adopted: the plurality of axial slits 40 are curved at the 1 st intersection 44 and the 2 nd intersection 45, respectively, and the 1 st circumferential sipe 42 opens in the axial slit 40 at the 2 nd intersection 45, and the 2 nd circumferential sipe 43 opens in the axial slit 40 at the 1 st intersection 44.

According to this configuration, the

circumferential sipes

42 and 43 and the circumferential slit 41 are opened at the

inflection points

44 and 45 of the axial slit 40, whereby a groove (the

circumferential sipes

42 and 43 and the circumferential slit 41) can be effectively opened, and the traction performance and the lateral sliding resistance can be improved.

As in the embodiments shown in fig. 1 to 6, 9, and 10, the following configurations may be adopted: the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 open to the axial slit 40 at the intersecting

portions

44, 45 where the block ends exhibit the convex shape in a plan view, and the circumferential slit 41 opens to the axial slit 40 at the intersecting

portions

44, 45 where the block ends exhibit the concave shape in a plan view.

According to this configuration, the angle between the corner of the circumferential slit 41 and the axial slit 40 can be set to the obtuse angle θ 2, and the uneven wear resistance at the corner can be improved as compared with a configuration (fig. 8) in which the intersection where the block end is formed in a mountain shape in a plan view of the circumferential slit 41 is open.

As in the embodiments shown in fig. 1 to 8 and 10, the plurality of axial slits 40 may be open at the land ends 4a and 4b on both sides in the tire axial direction AD.

With this configuration, the traction performance can be ensured by the axial slits 40.

As in the embodiment shown in fig. 1 or 5, the

land portions

1 and 2 may include: the 1 st land portion 1 disposed on the 3 rd side AD3 in the tire axial direction AD with respect to the tire equatorial plane TE, the 2 nd land portion 2 disposed on the 4 th side AD4 opposite to the 3 rd side AD3 in the tire axial direction AD with respect to the tire equatorial plane TE, the 1 st circumferential sipe 42 and the 2 nd circumferential sipe 43 of the 1 st land portion 1, and the axial slit 40 of the 2 nd land portion 2 do not overlap with each other when viewed in the tire axial direction AD.

According to this configuration, since the

circumferential sipes

42 and 43 of the 1 st land portion 1 and the axial slits 40 of the 2 nd land portion 2 are arranged in a dispersed manner in the tire circumferential direction CD, at least one of the

circumferential sipes

42 and 43 of the 1 st land portion 1 and the axial slits 40 of the 2 nd land portion 2 is likely to appear in the ground contact surface when the tire rolls, and therefore, the traction performance and the lateral sliding resistance performance can be effectively exhibited.

While the embodiments of the present invention have been described above with reference to the drawings, the specific configurations should not be construed as being limited to the embodiments. The scope of the present invention is defined by the scope of the claims, not by the description of the above embodiments, and includes all modifications equivalent in meaning and scope to the scope of the claims.

The configurations adopted in the above embodiments may be adopted in any other embodiments. The specific configuration of each portion is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the invention.

The configurations adopted in the above embodiments may be adopted in any other embodiments.

Claims

1. A pneumatic tire having a land portion extending in a tire circumferential direction,

the land portion has: a plurality of axial slits, and a plurality of 1 st blocks arranged in the tire circumferential direction,

the plurality of axial slits are open at least any one of the land ends on both sides in the tire axial direction,

the plurality of 1 st blocks each have: a1 st block end arranged on a1 st side in a tire circumferential direction, a2 nd block end arranged on a2 nd side opposite to the 1 st side in the tire circumferential direction, a circumferential slit extending in the tire circumferential direction and opened at both the 1 st block end and the 2 nd block end, a1 st circumferential sipe extending in the tire circumferential direction and opened at the 1 st block end and closed in the land portion, and a2 nd circumferential sipe extending in the tire circumferential direction and opened at the 2 nd block end and closed in the land portion,

the plurality of axial slits each have: a1 st intersecting portion which is an intersection between the circumferential slit opened at the 1 st block end and the axial slit, and a2 nd intersecting portion which is an intersection between the circumferential slit opened at the 2 nd block end and the axial slit,

the 1 st intersection and the 2 nd intersection at the same axial slit are different from each other in position in the tire axial direction,

the circumferential slit and the 2 nd circumferential sipe of the 1 st block adjacent to the 1 st side face each other with the axial slit interposed therebetween,

the circumferential slit and the 1 st circumferential sipe of the 1 st block adjacent to the 2 nd side face each other with the axial slit interposed therebetween.

2. A pneumatic tire according to claim 1,

in each of the 1 st blocks, the 1 st circumferential sipe is disposed on the 3 rd side in the tire axial direction of the circumferential slit, and the 2 nd circumferential sipe is disposed on the 4 th side opposite to the 3 rd side in the tire axial direction of the circumferential slit.

3. A pneumatic tire according to claim 2,

the length of the 1 st circumferential sipe and the 2 nd circumferential sipe in the tire circumferential direction is: the circumferential slit has a length in the tire circumferential direction of 20% to 50%.

4. A pneumatic tire according to any one of claims 1 to 3,

the circumferential slit and the axial slit each have: the bottom surface of the slit is partially provided with an open bottom knife groove pattern.

5. A pneumatic tire according to claim 4,

the plurality of axial slits are open at both the land end on the 3 rd side in the tire axial direction and the land end on the 4 th side opposite to the 3 rd side in the tire axial direction,

in each of the plurality of axial slits, the 1 st intersection portion is disposed on the 4 th side of the 2 nd intersection portion,

the plurality of axial slits each have: a1 st site from the 4 th land end to the 1 st intersection, a2 nd site from the 1 st intersection to the 2 nd intersection, and a3 rd site from the 2 nd intersection to the 3 rd land end,

the base sipes are formed in the 1 st portion and the 3 rd portion, and are not formed in the 2 nd portion.

6. A pneumatic tire according to claim 5,

the land portion has: a plurality of the 2 nd pattern blocks,

the plurality of 1 st blocks are divided in the tire circumferential direction by the axial slits respectively,

the plurality of 2 nd blocks are divided in the tire circumferential direction by the 1 st site, the 3 rd site, and the circumferential slit having the bottom sipe, respectively,

the 2 nd block has a length in the tire circumferential direction longer than: a length of the 1 st block in a tire circumferential direction.

7. A pneumatic tire according to any one of claims 1 to 3,

the plurality of axial slits are bent at the 1 st intersection and the 2 nd intersection, respectively,

said 1 st circumferential sipe being open at said 2 nd intersection in said axial slit,

the 2 nd circumferential sipe is open at the 1 st intersection in the axial slit.

8. A pneumatic tire according to claim 7,

the 1 st circumferential sipe and the 2 nd circumferential sipe are open at the axial slit at an intersection where the block end appears to be convex in a plan view,

the circumferential slit is open in the axial slit at an intersection where the block end appears as a concave shape in a plan view.

9. A pneumatic tire according to any one of claims 1 to 3,

the plurality of axial slits are open at land ends on both sides in the tire axial direction, respectively.

10. A pneumatic tire according to any one of claims 1 to 3,

the land portion includes: a1 st land portion disposed on a3 rd side in a tire axial direction from a tire equatorial plane, and a2 nd land portion disposed on a4 th side opposite to the 3 rd side in the tire axial direction from the tire equatorial plane,

the 1 st circumferential sipe and the 2 nd circumferential sipe of the 1 st land portion and the axial slit of the 2 nd land portion do not overlap with each other when viewed in the tire axial direction.