pneumatic tires

Abstract

Pneumatic tires (1), comprising: a central main groove (5) which is formed in a central zone of a tread area (2) in a tire width direction (TW) and extends in a tire circumferential direction (TC); a shoulder main groove (6, 6A, 6B) which is formed in the tread area (2) on one side of the ground contact end (GE, GE1, GE2) with respect to the central main groove (5) and extends in the tire circumferential direction (TC); a plurality of shoulder lateral grooves (8, 8A, 8B) formed in the tread area (2) extending in the tire width direction (TW), each having one end connected to the main shoulder groove (6, 6A, 6B) and another end terminating outside a ground contact end (GE, GE1, GE2) in the tire width direction (TW), and spaced apart in the tire circumferential direction (TC); a shoulder block (9, 9A, 9B) bounded by the main shoulder groove (6, 6A, 6B) and two shoulder lateral grooves (8, 8A, 8B) adjacent to each other in the circumferential direction (TC) of the plurality of shoulder lateral grooves (8, 8A, 8B); and a non-through lamellar slot (21) provided in the shoulder block (9, 9A, 9B), wherein the non-through lamellar slot (21) contains: a first deep area (21a) extending in the tire width direction (TW), one end which is connected to the main shoulder groove (6, 6A, 6B) and another end which is located in the shoulder block (9, 9A, 9B), and which includes a shallow groove (21f) and a first slat-slot body area (21f) the upper end of which is connected to a lower area of ​​the shallow groove (21f); a first shallow area (21b) extending in the tire width direction (TW) at a different angle (θ11) than an angle (θ8) of the first deep area (21a) to the tire width direction (TW), having one end connected to the first deep area (21a) and another end located in the shoulder block (9, 9A, 9B), and consisting of the same shallow groove (21f) as that (21f) of the first deep area (21a); ​​and a second deep area (21c) extending in the tire width direction (TW) at a different angle (θ9) than the angle (θ11) of the first flat area (21b) to the tire width direction (TW), offset in the tire circumferential direction (TC) relative to the first deep area (21a), having one end connected to the first flat area (21b) and another end located in the shoulder block (9, 9A, 9B), and containing the same flat groove (21f) as that (21f) of the first deep area (21a) and the first flat area (21b), and a second sipe body area (21g) whose upper end connects to a lower area of ​​the flat groove (21f), wherein a pair of side walls (21i) that bound the flat groove (21f) each have a chamfered shape in a sectional view perpendicular to an extension direction of the flat groove (21f), and the first deep area (21a), the first shallow area (21b) and the second deep area (21c) are each linear in tire radial view.

Description

Technical field

[0001] The present invention relates to a pneumatic tire. Technical background

[0002] A pneumatic tire according to EP 2 907 674 A1 comprises a tread section with a specific direction of rotation. The tread section includes a main shoulder groove located near a tread edge and a plurality of side shoulder grooves, each extending from the main shoulder groove to the tread edge to form a plurality of shoulder blocks. Each of the shoulder blocks has a zigzag leading edge with an outer corner having a first vertex formed between a long inclined side and a short inclined side.One of the shoulder blocks is provided with a plurality of shoulder lamellae extending at an angle of 0 to 20 degrees with respect to an axial direction of the tire, one of the shoulder lamellae having a deep section and a shallow section arranged to be in the same lateral position as the first vertex.

[0003] EP 0 788 900 A1 discloses a vehicle pneumatic tire with a directional tread pattern, which is divided into profile elements, for example blocks, by circumferential and transverse grooves, wherein profile elements are provided which have profile element areas of different stiffness due to a number of transverse fine cuts. Those profile elements which have profile element areas of different stiffness have an alternative sequence of softer and harder profile element areas, starting from the profile element area that first enters the road contact area.

[0004] To provide a pneumatic tire that enables compatible braking, handling, and cornering performance, JP 2011-051 431 A proposes that the pneumatic tire incorporate a plurality of rib blocks subdivided by circumferential and lateral grooves, be designed with a tire mounting direction, and be set with negative camber. Lateral steps, having the same width dimensions as the rib blocks and extending in the direction of the tread width, are provided on at least one side of the circumferential sidewalls of the rib blocks located on the inner tire mounting surface.A circumferential step section, having the same length dimensions as the rib section block and extending in the tire's circumferential direction, is provided on a side adjacent to the circumferential groove of the lateral end edges in the rib section block located on the tire's outer mounting surface. The maximum heights of the lateral step sections and the circumferential step section are less than the heights of the land section blocks.

[0005] JP 4 442 709 B2 discloses an M+S tire in which a plurality of wavy lamellar slots are formed in a shoulder block that is provided near a ground contact end of a tread area. Summary of the invention; Technical task

[0006] There is still room for improvement in conventional pneumatic tires, including the M+S tire disclosed in JP 4 442 709 B2, from the point of view of improving the stiffness of a shoulder block while ensuring steering stability on icy and snowy roads.

[0007] It is an object of the present invention to improve the stiffness of a shoulder block of a pneumatic tire while simultaneously ensuring steering stability on icy and snowy roads. Solution to the task

[0008] One aspect of the present invention creates a pneumatic tire as defined in claim 1.

[0009] The non-continuous sipe formed in the shoulder block has a first deep section and a second deep section, offset in the tire's circumferential direction. The first deep section and the second deep section are connected by a first shallow section, which extends at a different angle to the tire's width than the angles of the first and second deep sections. Accordingly, the first deep section, the second deep section, and the first shallow section are arranged in the shape of a polygonal line. The non-continuous sipe thus has these three elements: the first deep section, the second deep section, and the first shallow section. The shoulder block therefore acquires a multitude of edges at different positions and with different orientations.Accordingly, steering stability is improved on icy and snowy roads, especially steering stability during cornering.

[0010] The first and second deep sections, each featuring both the shallow groove and the lamellar slot body area, are connected by a first shallow section consisting of the shallow groove. In other words, the first deep section and the second deep section are connected to each other in the first shallow section only on the surface side of the tread area. This arrangement minimizes a reduction in shoulder block stiffness in the area containing the non-continuous lamellar slot. In other words, uniformity of shoulder block stiffness and sufficient overall shoulder block stiffness are maintained even when the non-continuous lamellar slot is present in the shoulder block.Accordingly, the ground contact pressure exerted on the shoulder block can be balanced, especially when a front-to-back load acts on the shoulder block in the tire's circumferential direction. Balancing the ground contact pressure can reduce or prevent uneven wear of the shoulder block. Furthermore, the sufficient rigidity ensured for the entire shoulder block improves steering stability on icy and snowy roads.

[0011] As described above, according to one aspect of the present invention, the pneumatic tire is able to improve the stiffness of the shoulder block while ensuring steering stability on icy and snowy roads.

[0012] The pneumatic tire may further include an additional sipe, provided in the shoulder block and arranged adjacent to the non-continuous sipe in the tire's circumferential direction. The additional sipe may comprise a first section opposite the first deep section of the non-continuous sipe in the tire's circumferential direction, a second section opposite the first shallow section of the non-continuous sipe in the tire's circumferential direction, and a third section opposite the second deep section of the non-continuous sipe in the tire's circumferential direction. The first depth of the first and third sections may be less than the second depth of the second section.

[0013] The additional lamellar slot, besides the non-continuous one, further increases the overall length of the shoulder block edges. This improves steering stability on icy and snowy roads, particularly when cornering.

[0014] The additional sipe in the shoulder block has a relatively shallow depth in the tire width direction in one area (the first and third sections of the additional sipe) where the non-continuous sipe has a relatively deep depth, i.e., in the area where the first and second deep sections are located. Conversely, the additional sipe in the shoulder block has a relatively deep depth in another area (the second section of the additional sipe) where the non-continuous sipe has a relatively shallow depth, i.e., in the area where the first shallow section is located. This configuration of the depths of the non-continuous sipe and the additional sipe balances the stiffness distribution of the shoulder block in the tire width direction.As a result, the ground contact pressure exerted on the shoulder block can be balanced, especially when a front-to-back load acts on the shoulder block in the tire's circumferential direction. Accordingly, the shoulder block's resistance to uneven wear is ensured.

[0015] The non-continuous lamellar slot may include: a second flat area extending in the tire width direction at a different angle than the angle of the second deep area to the tire width direction, an end connected to the second deep area, and another end located in the shoulder block and containing the same flat groove as that of the first deep area, the first flat area, and the second deep area;and a third deep area extending in the tire width direction at a different angle than the angle of the second shallow area to the tire width direction, offset in the tire circumference direction from the first deep area and the second deep area, having one end connected to the first shallow area and another end terminating in the shoulder block, containing the same shallow groove as that of the first deep area, the first shallow area, the second deep area and the second shallow area, and containing a third siped body area, the upper end of which connects to a lower portion of the shallow groove.

[0016] Each of the first deep section, the second deep section, and the third deep section can extend at an angle ranging from -20 degrees to 20 degrees to the tire width direction. The absolute value of the angle formed by each of the first flat section and the second flat section to the tire width direction can fall within a range of 2 degrees to 45 degrees.

[0017] The depth of the shallow groove can fall in a range from 0.05 times to 0.5 times the depth of the first deep area, the second deep area, and the third deep area. Effect of the invention

[0018] A pneumatic tire according to the present invention is able to improve both steering stability on icy and snowy roads and the stiffness of a shoulder block. Brief description of the drawing Fig. Figure 1 is a perspective view of an air tire according to an embodiment of the present invention; Fig. 2 is a flattened view of a tread area of ​​the in Fig. 1. The depicted pneumatic tire and the surrounding area of ​​the tread; Fig. 3 is a partially enlarged view of Fig. 2; Fig. Figure 4 is an enlarged view of a midrib; Fig. 5 is a section view along a line VV in Fig. 4; Fig. 6 is a section view along a line VI-VI in Fig. 4; Fig. Figure 7 is an enlarged view of a shoulder block; Fig. 8 is a sectional view along a line VIII-VIII of Fig. 7; Fig. 9 is a sectional view along a line IX-IX of Fig. 7; Fig. 10 is a sectional view along lines XX, X'-X' and X''-X'' in Fig. 7; Fig. Figure 11 is a sectional view along lines XI-XI and XI'-XI' in Fig. 7; Fig. Figure 12 is an enlarged view of an alternative to the midrib; and Fig. Figure 13 is an enlarged view of an alternative to the midrib. Description of embodiments

[0019] In the following description, the terms “upward to the right” and “downward to the right” may be used to express a slant in a top view or tire radial view of a structure with a longitudinal direction, such as a groove and a lamellar slot, formed in a tread area.

[0020] The term "top right" refers to a condition where the longitudinal direction of the structure and one of the tire's circumferential directions are aligned by rotating the tire's circumferential direction clockwise at an acute angle around the point of intersection of the structure's longitudinal direction and the tire's circumferential direction. The term "top right" also refers to a condition where the longitudinal direction of the structure and the tire's circumferential direction are aligned by rotating the tire's width direction counterclockwise at an acute angle around the point of intersection of the structure's longitudinal direction and the tire's width direction.

[0021] The term "down-right" refers to a condition where the longitudinal direction of the structure and the circumferential direction of the tire are aligned by rotating the circumferential direction of the tire counterclockwise at an acute angle around the point of intersection of the longitudinal direction of the structure and the circumferential direction of the tire. The term "down-right" also refers to a condition where the longitudinal direction of the structure and the circumferential direction of the tire are aligned by rotating the circumferential direction of the tire clockwise at an acute angle around the point of intersection of the longitudinal direction of the structure and the circumferential direction of the tire.

[0022] In the following description, a plus sign is assumed to be given to an angle “to the upper right” formed by the structure having the longitudinal direction, such as a groove and a lamellar slot formed in the tread area, to the tire circumference direction or to the tire width direction in a tire radial view, and a minus sign is given to an angle “to the lower right” formed in a similar way. (Overview of the running track area and its surroundings)

[0023] Fig. 1, Fig. 2 to Fig. Figure 3 each represents a tread area 2 of a pneumatic tire (hereinafter referred to as tire) 1 made of rubber according to an embodiment of the present invention and a surrounding area of ​​the tread area 2. The tire 1 is an M+S tire.

[0024] A tire circumference direction in the figures is designated by a reference symbol TC, and a tire width direction is designated by a reference symbol TW. A center line (equatorial line) of the tread area 2 in the tire width direction is designated by a reference symbol CL. Ground contact ends of one and the other end of the tread area 2 in the tire width direction are designated by the reference symbols GE1 and GE2, respectively. In the following description, the ground contact ends GE1 or GE2 may simply be referred to as one ground contact end GE if a distinction between the two ground contact ends GE1 and GE2 is not particularly necessary.

[0025] In this description, a zone of a tire's outer circumference located between two ground contact points GE1 and GE2 is referred to as the tread area 2. An area located outside the tread area 2 in the tire's width direction, intersecting a tire axial direction substantially at a right angle, and having a flat shape or relatively small curvature, is referred to as a side area 3. An area connecting the tread area 2 and the side area 3, and curved with a relatively strong curvature, is referred to as a shoulder area 4.

[0026] A central main groove 5, extending in the circumferential direction of the tire, is formed in a central zone of the tread area 2 in the width direction of the tire, more precisely, on the center line CL. The central main groove 5 does not have a linear shape, but rather a meandering or zigzag shape in the radial view of the tire.

[0027] Shoulder grooves 6A and 6B, extending in the circumferential direction of the tire, are formed in the tread area 2 on the sides of the ground contact ends GE1 and GE2, respectively, with respect to the central groove 5. The two shoulder grooves 6A and 6B are each adjacent to the central groove 5 in the tire width direction. Each of the shoulder grooves 6A and 6B does not have a linear shape, but rather a meandering or zigzag shape in the tire radial view. In the following description, the shoulder groove 6A or 6B can simply be referred to as a shoulder groove 6 if a distinction between the two shoulder grooves 6A and 6B is not particularly necessary.

[0028] A central rib 7A, extending in the circumferential direction of the tire and formed in the central zone of the tread area 2 in the tire width direction, is bounded by the central main groove 5 and the shoulder main groove 6A. A central rib 7B, extending in the circumferential direction of the tire and formed in the central zone in the tire width direction, is bounded by the central main groove 5 and the shoulder main groove 6B. In the following description, the central rib 7A or 7B may simply be referred to as a central rib 7 if a distinction between the two central ribs 7A and 7B is not particularly necessary.

[0029] A plurality of shoulder lateral grooves 8A and 8B spaced apart in the tire circumferential direction are provided in two shoulder zones of the tread area 2 on one side and the other side in the tire width direction, i.e., two zones adjacent to the ground contact points GE1 and GE2.

[0030] Each of the shoulder lateral grooves 8A extends substantially in the tire width direction, and one end of each is connected to the main shoulder groove 6A, while the other end extends beyond the ground contact end GE1 and the shoulder area 4. The other end of each of the shoulder lateral grooves 8A is located in the side area 3.

[0031] Similarly, each of the shoulder lateral grooves 8B extends substantially in the tire width direction, with one end of each end connected to the shoulder main groove 6B, and the other end of each end located in the side area 3 outside the ground contact end GE2 and the shoulder area 4 in the tire width direction.

[0032] In the following description, the shoulder lateral grooves 8A or 8B may simply be referred to as shoulder lateral grooves 8 if a distinction between the two shoulder lateral grooves 8A and 8B is not particularly needed.

[0033] A plurality of shoulder blocks 9A, each bounded by the main shoulder groove 6A and the two shoulder lateral grooves 8A adjacent to each other in the circumferential direction of the tire, is arranged in the circumferential direction of the tire on a region of the tread area 2 on the side of the ground contact end GE1.

[0034] Each of the shoulder blocks 9A has an elongated shape in the tire width direction. Each inner end of the shoulder blocks 9A, in the tire width direction, lies in the tread area 2. Each of the shoulder blocks 9A extends beyond the ground contact end GE1 and the shoulder area 4 outwards in the tire width direction. Each outer end of the shoulder blocks 9A, in the tire width direction, lies in the sidewall area 3.

[0035] Similarly, a plurality of shoulder blocks 9B, each bounded by the main shoulder groove 6B and the two adjacent shoulder lateral grooves 8B in the tire circumference direction, are arranged in the tire circumference direction in a region of the tread area 2 on the side of the ground contact end GE2. Each of the shoulder blocks 9B has an elongated shape in the tire width direction. Each inner end of the shoulder blocks 9B in the tire width direction lies in the tread area 2, while each outer end of the shoulder blocks 9B in the tire width direction lies in the side area 3.

[0036] In the following description, shoulder blocks 9A or 9B may simply be referred to as shoulder blocks 8 if a distinction between shoulder blocks 9A and 9B is not particularly necessary.

[0037] A plurality of central grooves 11 are provided in the central rib 7 at fixed intervals in the circumferential direction of the tire. Each of the central grooves 11 is inclined upwards and to the right. One end (proximal end) of each of the central grooves 11 is connected to the central main groove 5, and the other end (distal end) terminates in the central rib 7. Each distal end of the central grooves 11 has a curved shape. As detailed below, each of the pair of sidewalls 11d that bound each of the central grooves 11 has a shoulder 11h and forms two edges, i.e., a major edge 11i and a minor edge 11j (see also Fig. 5) Paragraph 11h only needs to be provided on one of the pair of side walls 11d.

[0038] A plurality of side grooves 12 are provided in the central rib 7 at fixed intervals in the tire's circumferential direction. Each of the side grooves 12 is inclined upwards and to the right. One end (proximal end) of each of the side grooves 12 is connected to the shoulder main groove 6, and the other end (distal end) terminates in the central rib 7. As detailed below, each of the side grooves 12, consisting of a pair of sidewalls 12b, has a shoulder 12f and forms two edges, i.e., a main edge 12g and a secondary edge 12h (see also Fig. 6). Paragraph 12f only needs to be provided on one of the pair of side walls 12b.

[0039] Two straight lamellar slots 13A and 13B are provided separately in the circumferential direction of the tire in the center rib 7 at each of the areas opposite the center grooves 11 in the tire width direction. One end (proximal end) of each of the straight lamellar slots 13A and 13B is connected to the shoulder main groove 6, and the other end (distal end) terminates in the center rib 7. Both straight lamellar slots 13A and 13B are inclined downwards and to the right. The respective straight lamellar slots 13A and 13B extend substantially parallel to each other. The center rib 7 contains straight lamellar slots 13C inclined downwards and to the right, with a gap left between them and the straight lamellar slot 13B in the circumferential direction of the tire. One end (proximal end) of each of the straight lamellar slits 13C is connected to the main shoulder groove 6, and the other end (distal end) terminates in the midrib 7.

[0040] Two straight lamellar slots 14A and 14B are provided separately in the circumferential direction of the tire in the central rib 7 at each of the areas opposite the side grooves 12 in the tire width direction. One end (proximal end) of each of the straight lamellar slots 14A and 14B is connected to the central main groove 5, and the other end (distal end) terminates in the central rib 7. Both straight lamellar slots 14A and 14B are inclined downwards and to the right. Furthermore, the straight lamellar slots 14A and 14B extend substantially parallel to each other. The central rib 7 contains straight lamellar slots 14C inclined downwards and to the right, with a gap left between them and the straight lamellar slot 14B in the circumferential direction of the tire. One end (proximal end) of each of the straight lamellar slits 14C is connected to the main shoulder groove 6, and the other end (distal end) terminates in the midrib 7.

[0041] The central rib 7 contains three types of corrugated lamellar slots 15A to 15C in an area between each of the central grooves 11 and the side groove 12 adjacent to the corresponding central groove 11 in the tire's circumferential direction. Each of the corrugated lamellar slots 15A to 15C is inclined upwards and to the right. One end of the corrugated lamellar slot 15A adjacent to the center groove 11 in the circumferential direction of the tire is connected to the central main groove 5, and the other end terminates in the central rib 7. One end of the corrugated lamellar slot 15C adjacent to the side groove 12 in the circumferential direction of the tire is connected to the shoulder main groove 6, and the other end terminates in the central rib 7. One end of the corrugated lamellar slot 15B located between the corrugated lamellar slots 15A and 15C is connected to the central main groove 5, and the other end is connected to the shoulder main groove 6.

[0042] As detailed below, each of the pair of sidewalls 8d, which delimit each of the shoulder lateral grooves 8, has a shoulder 8h. A corner of the shoulder block 9 extends in the tire width direction and has two edges, i.e., a major edge 9a and a minor edge 9b (see Fig. 8 and Fig. 9). Paragraph 8h only needs to be provided on one of the pair of side walls 8d.

[0043] A single, non-continuous lamellar slot 21, extending in the overall direction of the tire width, is provided in a central region of each of the shoulder blocks 9 in the circumferential direction of the tire. One end of the non-continuous lamellar slot 21 is connected to the main shoulder groove 6, and the other end extends beyond the ground contact end GE outwards in the direction of the tire width. The other end of the non-continuous lamellar slot 21 terminates at a boundary between the shoulder region 4 and the side region 3 (see Fig. 2) As detailed below, the non-continuous lamellar slot 21 has alternating deep areas 21a, 21c and 21e and shallow areas 21b and 21d extending in different directions with respect to the tire width direction, and generally has a zigzag shape in the tire radial view.

[0044] A pair of compound lamellar slots 22, provided in the shoulder block 9, is located on one side and the other side of each of the non-through lamellar slots 21 in the tire's circumferential direction. One end of the compound lamellar slots 22 is connected to the main shoulder groove 6, and the other end terminates in the shoulder block 9. Each of the compound lamellar slots 22 contains a straight lamellar slot area 22a on one end side and a wavy lamellar slot area 22b on the other end side.

[0045] A pair of straight lamellar slots 23, extending substantially in the tire width direction, is provided in a region outside each of the shoulder blocks 9 in the tire width direction. One end of each of the straight lamellar slots 23 lies in the shoulder region 4, and the other end lies in the side region 3.

[0046] Continuous protrusion areas 24 are provided in side area 3. (Details of the midrib)

[0047] The midrib 7 is described below mainly with reference to Fig. 4 described in detail. As described above, the central rib 7 contains the central notches 11, the side notches 12, the straight lamellar slots 13A to 13C, the straight lamellar slots 14A to 14C and the wavy lamellar slots 15A to 15C.

[0048] Each of the central grooves 11 comprises a body section 11a, the proximal end of which is connected to the central main groove 5, and a distal end section 11b, which is bent with respect to a distal end of the body section 11a. The width of the central groove 11 gradually decreases from a proximal end of the body section 11a to a distal end of the distal end section 11b. According to the present embodiment, the angle θ1 of the body section 11a with respect to the tire circumference direction is 73 degrees. The angle θ2 of the distal end section 11b with respect to the tire circumference direction is 30 degrees, which is smaller than the angle θ1. The angle θ1 can be set in a range from 30 degrees to 85 degrees, while the angle θ2 can be set within a range from 0 degrees to 60 degrees, which is smaller than the angle θ1.

[0049] Also with regard to Fig. In the present embodiment, each of the central grooves 11 is bounded by a bottom wall 11c and a pair of opposing side walls 11d. Each of the side walls 11d comprises a first region 11e, a second region 11f, and a third region 11g. According to the present embodiment, the first region 11e, the second region 11f, and the third region 11g of each of the side walls 11d are all flat surfaces. The first region 11e extends substantially in a tire radial direction from the bottom wall 11c to a surface of the central rib 7, perpendicular to a direction of extension of the central groove 11 in a sectional view. In the same sectional view, the second region 11f extends substantially in the tire circumferential direction, with one end of the second region 11f being connected to an upper end of the first region 11e to increase the width of the central groove 11.In the same sectional view, the third region 11g has a lower end connected to the other end of the second region 11f and an upper end connected to the surface of the central rib 7.

[0050] In the sectional view, perpendicular to the direction of extension of the central groove 11, the direction of extension of each of the sidewalls 11d changes sharply at a junction between the first region 11e and the second region 11f. More precisely, the shoulder 11h is formed at the junction between the first region 11e and the second region 11f. The shoulder 11h thus formed creates two edges at an opening edge of the central groove 11, i.e., the main edge 11i on the surface side of the central rib 7 and the secondary edge 11j within the main edge 11i in the tire radial direction. The main edge 11i is formed at a junction between the surface of the central rib 7 and the third region 11g of the sidewall 11d. The secondary edge 11j is formed at a junction between the first region 11e of the sidewall 11d and the second region 11f of the sidewall 11d.

[0051] The width W1 of the shoulder 11h (width of the second region 11f of the side wall 11d) can be set within a range of 0.1 to 1 times the width W2 of the central notch 11 at the first region 11e. The width W1 can be set within a range of 0.3 to 3 mm. The width W2 of the central notch 11 can be set within a range of 1.2 to 10 mm. Accordingly, the width of the central notch 11, including the width W1 of the shoulder 11h, can be set within a range of 1.8 to 16 mm. The depth position DE1 of the shoulder 11h from the surface of the central rib 7 (height of the third region 11g of the side wall 11d) can be set within a range of 0.05 to 0.5 times the depth DE2 of the central notch 11. The depth DE2 of the center notch 11 can be set within a range of 2 to 13 mm.According to the present embodiment, an angle γ1 formed by the second region 11f of the side wall 11d to the surface of the central rib 7 in the sectional view, perpendicular to the direction of extension of the central notch 11, is 0°. The angle γ1 can be set within a range of -30 degrees to 30 degrees. (The angle γ1 has a positive value in the clockwise direction.) Fig. 5 on.)

[0052] The width of the side groove 12 gradually decreases from the proximal end to the distal end. According to the present embodiment, the angle θ3 of the side groove 12 to the tire circumference is 70 degrees. The angle θ3 can be set within a range of 30 degrees to 85 degrees.

[0053] With reference to Fig. In the present embodiment, the side groove 12 is bounded by a bottom wall 12a and a pair of opposing side walls 12b. Each of the side walls 12b comprises a first region 12c, a second region 12d, and a third region 12e. According to the present embodiment, the first region 12c, the second region 12d, and the third region 12e of the side wall 12b are all flat surfaces. The first region 12c extends substantially in the tire radial direction from the bottom wall 12a to the surface of the central rib 7, perpendicular to one direction of extension of the side groove 12 in a sectional view. In the same sectional view, the second region 12d extends substantially in the tire circumferential direction, with one end connected to an upper end of the first region 12c to increase the width of the side groove 12.In the same sectional view, the third region 12e has a lower end connected to the other end of the second region 12d and an upper end connected to the surface of the central rib 7.

[0054] In the sectional view, perpendicular to the direction of extension of the side groove 12, the direction of extension of the sidewall 12b changes sharply at a junction between the first region 12c and the second region 12d. More precisely, the shoulder 12f is formed at the junction between the first region 12c and the second region 12d. The shoulder 12f thus formed creates two edges on an opening edge of the side groove 12, i.e., the main edge 12g on the surface side of the center rib 7 and the secondary edge 12h, located within the main edge 12g in the tire radial direction. The main edge 12g is formed at a junction between the surface of the center rib 7 and the third region 12e of the sidewall 12b. The secondary edge 12h is formed at a junction between the first region 12c and the second region 12d of the sidewall 12b.

[0055] The width W3 of the step 12f (width of the second region 12d of the side wall 12b) can be set within a range of 0.1 to 1.0 times the width W4 of the side notch 12 at the first region 12c. The width W4 can be set within a range of 0.3 mm to 3 mm. The width W4 of the side notch 12 can be set within a range of 1.2 to 10 mm. Accordingly, the width of the side notch 12, including the width W3 of the step 12f, can be set within a range of 1.8 to 16 mm. The depth position DE3 of the step 12f from the surface of the side notch 12 (height of the third region 12e of the side wall 12b) can be set within a range of 0.05 to 0.5 times the depth DE4 of the side notch 12. The depth DE4 of the side notch 12 can be set within a range of 2 to 13 mm.According to the present embodiment, an angle γ2 formed by the second region 12d of the side wall 12b to the surface of the side notch 12 in the sectional view, perpendicular to the direction of extension of the side notch 12, is 0°. The angle γ2 can be set within a range of -30 degrees to 30 degrees. (The angle γ2 has a positive value in the clockwise direction.) Fig. 6 on.)

[0056] As described above, the center rib 7 contains two straight lamellar slots 13A and 13B in the area opposite the center groove 11 in the tire width direction. The condition of "opposite in the tire width direction" refers here to a condition in which at least part of the straight lamellar slots 13A and 13B overlaps the center groove 11 in the tire circumference direction. While the center groove 11 is inclined upwards to the right (angle θ1 is in the range of 30° to 85°, and angle θ2 is in the range of 0° to 60°), the straight lamellar slots 13A and 13B are inclined downwards to the right. An angle θ4 of the straight lamellar slots 13A and 13B to the tire radial direction can be set within a range of -85° to -30°. In this case, the straight lamellar slots 13A and 13B extend such that they form the angle θ4 with a different sign than the sign of the angles θ1 and θ2 of the center notch 11 to the tire circumferential direction.Accordingly, an imaginary line indicating a direction of extension of the center groove 11, and imaginary lines indicating directions of extension of the straight lamellar slots 13A and 13B, form a polygonal line extending in a direction in the tire circumferential direction (in . Fig. 4 upwards).

[0057] The distal end of the central groove 11 and the distal end closest to the central main groove 5, beneath the distal ends of the straight lamellar slots 13A and 13B opposite the central groove 11 in the tire width direction, may lie in the central zone of the central rib 7 in the tire width direction. More precisely, these distal ends may lie within a region of width CRW1 whose center lies in the center of the central rib 7 in the width direction (indicated by the reference symbol CRC in Fig. 4) The width CRW1 can be set here within a range from 0.1 times to 0.4 times the width CRW0 (average width) of the central rib 7.

[0058] The width of each straight louver slot 13A and 13B can be specified within a range of 0.3 to 1.5 mm. The depth of each straight louver slot 13A and 13B can be specified within a range of 2 to 13 mm.

[0059] As described above, the two straight sipes 14A and 14B are located in the center rib 7 in the area opposite the side groove 12 in the tire width direction. The term "opposite in the tire width direction" refers to a condition where at least part of the straight sipes 14A and 14B overlap the side groove 12 in the tire circumference direction. While the side groove 12 is inclined upwards to the right (the angle θ3 is in the range of 30° to 85°), the straight sipes 14A and 14B are inclined downwards to the right. The angle θ5 of the straight sipes 14A and 14B to the tire radial direction can be set within a range of -85° to -30°. In this case, the straight lamellar slots 14A and 14B extend such that they form the angle θ5 with a different sign than the sign of the angle θ3 of the side groove 12 to the tire circumferential direction.Accordingly, an imaginary line indicating a direction of extension of the side groove 12, and imaginary lines indicating directions of extension of the straight lamellar slots 14A and 14B, form a polygonal line extending in a direction in the tire circumferential direction (in . Fig. 4 downwards).

[0060] The distal end of the side groove 12 and the distal end closest to the shoulder main groove 6, under the distal ends of the straight lamellar slots 14A and 14B opposite the side groove 12 in the tire width direction, may lie in a region of the width CRW1 described above.

[0061] The width of each straight louver slot 14A and 14B can be specified within a range of 0.3 to 1.5 mm. The depth of each straight louver slot 14A and 14B can be specified within a range of 2 to 13 mm. (Details of the lateral scapular groove and the shoulder block)

[0062] The shoulder lateral grooves 8 and the shoulder blocks 9 are described below mainly with reference to Fig. 7 described in detail. As described above, each of the shoulder blocks 9 contains the one non-continuous lamellar slot 21, the two compound lamellar slots 22 and the two straight lamellar slots 23.

[0063] Each of the shoulder lateral grooves 8 contains an inner region 8a, connected to the main shoulder groove 6, and an outer region 8b, which extends outwards beyond the ground contact end GE in the tire width direction, with one end connected to the inner region 8a. Also, with regard to Fig. 2 the other end of the outer area 8b at the border between the shoulder area 4 and the side area 3, as described above.

[0064] The shoulder lateral groove 8 extends essentially in the tire width direction. However, the inner region 8a and the outer region 8b have different inclinations in the tire width direction. The inner region 8a is inclined upwards and to the right. An angle θ6 of the inner region 8a to the tire width direction can be specified within a range of 2 degrees to 45 degrees. The outer region 8b is inclined downwards and to the right. An angle θ7 of the outer region 8b to the tire width direction can be specified within a range of -20 degrees to -2 degrees.

[0065] The size of the inner area 8a of the shoulder lateral groove 8 in the tire width direction is smaller than the size of the outer area 8b of the shoulder lateral groove 8 in the tire width direction. The length of the inner area 8a can be specified within a range of 0.1 to 0.4 times the length of the outer area 8b.

[0066] Also with reference to Fig. 8 and Fig. In this embodiment, the width W5 of the inner region 8a of the shoulder lateral groove 8 is set smaller than the width W6 of the outer region 8b of the shoulder lateral groove 8. The width W5 of the inner region 8a of the shoulder lateral groove 8 gradually decreases towards the main shoulder groove 6. According to this embodiment, the depth DE5 of the inner region 8a of the shoulder lateral groove 8 is matched to the depth DE6 of the outer region 8b of the shoulder lateral groove 8. The depth DE5 of the inner region 8a can be set smaller than the depth DE6 of the outer region 8b. Each of the depths DE5 and DE6 of the shoulder lateral groove 8 can be set within a range of 2 to 13 mm.

[0067] Further with reference to Fig. 8 and Fig. In the present embodiment, the shoulder lateral groove 8 is bounded by a bottom wall 8c and a pair of opposing side walls 8d. Each of the side walls 8d comprises a first region 8e, a second region 8f, and a third region 8g. According to the present embodiment, the first region 8e, the second region 8f, and the third region 8g of the side wall 8d are all flat surfaces. The first region 8e extends substantially in the tire radial direction from the bottom wall 8c to the surface of the shoulder block 9, perpendicular to one direction of extension of the shoulder lateral groove 8 in a sectional view. In the same sectional view, the second region 8f extends substantially in the tire circumferential direction, with one end of the second region 8f being connected to an upper end of the first region 8e to increase the width of the shoulder lateral groove 8.In the same sectional view, the third area 8g has a lower end connected to the other end of the second area 8f and an upper end connected to the surface of the shoulder block 9.

[0068] In the sectional view, perpendicular to the direction of extension of the shoulder lateral groove 8, the direction of extension of the sidewall 8d changes sharply at a junction between the first region 8e and the second region 8f. More precisely, the step 8h is formed at the junction between the first region 8e and the second region 8f. As described above, the shoulder lateral groove 8 and the main shoulder groove 6 define the shoulder block 9. More precisely, the sidewall 8d of the shoulder lateral groove 8 and the surface of the tread area 2 create a corner of the shoulder block 9 that extends in the tire width direction. Due to the step 8h thus provided on the sidewall 8d of the shoulder lateral groove 8, this corner of the shoulder block 9, extending in the tire width direction, has not a single edge, but two edges.More precisely, the corner of the shoulder block 9, extending in the tire width direction, has a major edge 9a on the side of the front surface of the shoulder block 9 and a minor edge 9b within the major edge 9a in the tire radial direction. The major edge 9a is formed at a junction between the surface of the shoulder block 9 and the third region 8g of the sidewall 8d of the shoulder lateral groove 8. The minor edge 9b is formed at a junction between the first region 8e of the sidewall 8d and the sidewall 8d of the shoulder lateral groove 8.

[0069] The width W7 of the shoulder 8h (width of the second region 8f of the side wall 8d) can be set within a range of 0.1 to 1.0 times each of the widths W5 and W6 of the shoulder lateral groove 8 at the first region 8e. The depth position DE7 of the shoulder 8h from the surface of the shoulder block 9 (height of the third region 8g of the side wall 8d) can be set within a range of 0.05 to 0.5 times each of the depths DE5 and DE6 of the shoulder lateral groove 8. According to the present embodiment, an angle y3 formed by the second region 8f of the side wall 8d to the surface of the shoulder block 9 in the sectional view, perpendicular to the direction of extension of the shoulder lateral groove 8, is 0°. The angle γ3 can be set within a range of -30 degrees to 30 degrees. (The angle γ3 has a positive value in the clockwise direction in Fig. 8 and Fig. 9 on.)

[0070] Each of the non-continuous lamellar slots 21 extends essentially in a zigzag shape in the tire width direction from the main shoulder groove 6 to the boundary between the shoulder area 4 and the side area 3 (see also Fig. 2) in the tire radial view. Each of the non-continuous sipes 21 contains two types of alternatingly arranged elements, i.e., deep areas 21a, 21c, and 21e, and shallow areas 21b and 21d. These elements are arranged in the following order, from the main shoulder groove 6 outwards in the tire width direction: deep area 21a, shallow area 21b, deep area 21c, shallow area 21d, and deep area 21e. More precisely, one end of the deep area 21a is connected to the main shoulder groove 6, and the other end is connected to one end of the shallow area 21b. The other end of the shallow area 21b is connected to one end of the deep area 21c. The other end of the deep area 21c is connected to one end of the shallow area 21d. The other end of the shallow area 21d is connected to one end of the deep area 21e. The other end of the deep area 21e ends in shoulder block 9.

[0071] Also with reference to Fig. 10 and Fig. 11 The non-continuous lamellar slot 21 contains a single shallow groove 21f, extending from the deep area 21a, which is the element connected to the main shoulder groove 6, to the deep area 21e, which is the element furthest from the main shoulder groove 6. In other words, the shallow groove 21f is common to all the elements forming the non-continuous lamellar slot 21, i.e., the deep areas 21a, 21c, 21e and the shallow areas 21b, 21d. The shallow groove 21f opens to the surface of the shoulder block 9.

[0072] Lamellar slot body regions 21f, 21g and 21h, which are connected to the shallow groove 21f, are further provided in the deep regions 21a, 21c and 21e. Upper ends of the lamellar slot body regions 21f, 21g and 21h are connected to a lower part of the shallow groove 21f. According to the present embodiment, a lamellar slot body region 21 is a straight lamellar slot.

[0073] Each of the shallow areas 21b and 21d lacks a lamellar slot body area, but consists only of the shallow groove 21f. Accordingly, the lamellar slot body areas 21f, 21g, and 21h of the deep areas 21a, 21c, and 21e are not connected to each other. In other words, the deep area 21a and the deep area 21c are spatially connected only by the shallow groove 21f, which forms the shallow area 21b located between the deep area 21a and the deep area 21c. Similarly, the deep area 21c and the deep area 21e are spatially connected only by the shallow groove 21f, which forms the shallow area 21d located between the deep area 21c and the deep area 21e.

[0074] With reference to Fig. According to the present embodiment, all elements forming the non-continuous lamellar slot 21, i.e., the deep areas 21a, 21c, and 21e and the shallow areas 21b and 21d, are linear in the tire radial view. Their size, i.e., their length in the tire width direction, is determined such that a length L1 of the deep area 21a is substantially equal to a length L2 of the deep area 21c, and that a length L3 of the deep area 21e is sufficiently greater than either length L1 or L2 of the deep areas 21a and 21c. Each of the lengths L1, L2, and L3 of the deep areas 21a, 21c, and 21e can be specified within a range of 0.1 to 0.5 times the total length L4 of the shoulder block 9 in the tire width direction. Each of the lengths L5 and L6 of the shallow areas 21b and 21d is sufficiently smaller than each of the lengths L1, L2 and L3 of the deep areas 21a, 21c and 21e.Each of the lengths L5 and L6 of the shallow areas 21b and 21d can be set within a range of 0.1 times to 0.5 times the smallest length among the lengths L1, L2 and L3 of the deep areas 21a, 21c and 21e.

[0075] The deep area 21c is offset relative to the deep area 21a in the tire circumferential direction. The deep area 21e is offset relative to the deep area 21c in the tire circumferential direction. According to the present embodiment, the deep area 21c is directed downwards in Fig. 7 offset against the deep area 21a, while the deep area 21e is offset downwards into Fig. 7 is offset against the deep area 21c. According to the present embodiment, each of the angles θ8, θ9 and θ10 formed by the deep areas 21a, 21c and 21e with respect to the tire width direction is 0°. Each of the angles θ8 to θ10 can be set in a range from -20 degrees to 20 degrees.

[0076] According to the present embodiment, the flat areas 21b and 21d are inclined downwards and to the right. Each of the angles θ11 and θ12 formed by the flat areas 21b and 21d with respect to the tire width direction is -30 degrees. In a case where the deep areas 21a, 21c, and 21e are offset as in the present embodiment, each of the angles θ11 and θ12 can be set within a range of -45 degrees to -2 degrees. In a case where, unlike in the present embodiment, the deep area 21c is inclined upwards in Fig. 7 is offset against the deep area 21a, and in which the deep area 21e is moved upwards into Fig. Since the 7th section is offset from the deep area 21c, each of the shallow areas 21b and 21d has a tilt to the upper right. In this case, each of the angles θ11 to θ12 can be set within a range of 2 degrees to 45 degrees. Accordingly, each of the absolute values ​​of the angles θ11 to θ12 can be set within a range of 2 degrees to 45 degrees.

[0077] Also with reference to Fig. 10 and Fig. 11 The flat groove 21f is bounded by a pair of sidewalls 21i opposing each other in the tire circumferential direction. Each of the sipe-slot body regions 21f, 21g and 21h is bounded by a bottom wall 21j, which opposes an opening of the flat groove 21f in the tire radial direction, and a pair of sidewalls 21k.

[0078] Each of the side walls 21i that bound the flat groove 21f has a chamfered shape in a sectional view, perpendicular to one direction of extension of the flat groove 21f. More precisely, in this sectional view, the side wall 21i is inclined towards the surface of the shoulder block 9. According to the present embodiment, the angle of inclination γ4 of the right side wall 21i to the surface of the shoulder block 9 is Fig. 10 and Fig. 11 45 degrees. The inclination angle γ4 can be set in a range from 5 degrees to 60 degrees. In the present embodiment, the inclination angle of the right side wall 21i to the surface of the shoulder block 9 is 45 degrees. Fig. 10 and 11 -45 degrees and can be set in a range from -60 degrees to -5 degrees. In other words, an absolute value of the inclination angle γ4 of the side wall 21e to the shoulder block 9 can be set in a range from 5 degrees to 60 degrees.

[0079] The depth DE8 of the shallow groove 21f can be specified within a range of 0.05 to 0.5 times the total depth DE9 of the deep areas 21a, 21c, and 21e (the sum of the depth DE8 of the shallow groove 21f and the depth DE9 of the lamellar slot body areas 21f, 21g, and 21h). A maximum width of the shallow groove 21f, i.e., a maximum width W8 of an opening in the shallow groove 21f (corresponding to openings in the deep areas 21a, 21c, and 21e and the shallow areas 21b and 21d) in a sectional view perpendicular to the direction of extension of the shallow groove 21f, can be specified within a range of 1.2 to 5 times the width W9 of the lamellar slot body areas 21f, 21g, and 21h.

[0080] The straight sipe area 22a of the compound sipe 22 is located in a region corresponding to an inner region 8a (with a relatively small groove width W5) of the shoulder lateral groove 8 in the tire's circumferential direction. Accordingly, a portion of the straight sipe area 22a overlaps the inner region 8a in the tire's width direction. The wavy sipe area 22b of the compound sipe 22 is located in a region corresponding to the outer region 8b (with a relatively large groove width W6) of the shoulder lateral groove 8 in the tire's circumferential direction. Accordingly, the wavy sipe area 22b overlaps the outer region 8b in the tire's width direction.

[0081] The depth of the areas of the compound lamellar slot 22 (specified by reference numbers 22c, 22e and 22g), which correspond to the deep areas 21a, 21c and 21e of the non-continuous lamellar slot 21 in the tire circumferential direction, is specified as smaller than the depth of areas of the compound lamellar slot 22 (specified by reference numbers 22d and 22f), which correspond to the shallow areas 21b and 21d of the non-continuous lamellar slot 21 in the tire circumferential direction.

[0082] The main features of tire 1 according to the present embodiment include the following.

[0083] The non-continuous sipe 21 formed in the shoulder block 9 has deep sections 21a, 21c, and 21e, which are offset in the tire's circumferential direction. Deep section 21a and deep section 21c are connected by shallow section 21b, which extends at a different angle to the tire's width than deep section 21a and deep section 21c. Similarly, deep section 21c and deep section 21e are connected by shallow section 21d, which extends at a different angle to the tire's width than deep section 21c and deep section 21e. The non-continuous sipe 21 has these six elements: deep sections 21a, 21c, and 21e, and shallow sections 21b and 21d. Shoulder block 9 therefore has a large number of edges at different positions and with different orientations.Accordingly, steering stability is improved on icy and snowy roads, especially steering stability during cornering.

[0084] Deep regions 21a, 21c, and 21e, which contain both the shallow groove 21e and the lamellar slot trunk regions 21f, 21g, and 21h, are connected via shallow regions 21b and 21d, which consist only of the shallow groove 21e. In other words, the deep regions 21a, 21c, and 21e are interconnected at the shallow regions 21b and 21d only on the surface side of the shoulder block 9. This arrangement minimizes a reduction in the stiffness of the shoulder block in the region containing the non-continuous lamellar slot 21. In other words, uniformity of stiffness and sufficient overall stiffness of the shoulder block 9 are maintained even when the non-continuous lamellar slot 21 is present in the shoulder block 9.Accordingly, the ground contact pressure exerted on the shoulder block 9 can be balanced, particularly when a front-to-rear load acts on the shoulder block 9 in the circumferential direction of the tire. This balancing of the ground contact pressure can reduce or prevent uneven wear of the shoulder block 9. Furthermore, the sufficient rigidity ensured for the entire shoulder block 9 maintains advantageous steering stability on icy and snowy roads.

[0085] As described above, the pneumatic tire 1 according to the present embodiment is able to improve the stiffness of the shoulder block 9 and thereby ensure steering stability on icy and snowy roads.

[0086] The compound lamellar slot 22 provided in the shoulder block 9 in addition to the non-continuous lamellar slot 21 increases the overall length of the edges of the shoulder block 9. Accordingly, steering stability on icy and snowy roads is improved, in particular steering stability during cornering.

[0087] As described above, the depth of areas 22c, 22e, and 22g of the compound sipe 22, corresponding to the deep areas 21a, 21c, and 21e of the non-continuous sipe 21 in the circumferential direction of the tire, is set smaller than the depth of areas 22d and 22g of the compound sipe 22, corresponding to the shallow areas 21b and 21d of the non-continuous sipe 21 in the circumferential direction of the tire. In this case, the depth of the compound sipe 22 corresponding to the area of ​​the non-continuous sipe 21 containing the deep areas 21a, 21c, and 21e is relatively small, while the depth of the compound sipe 22 corresponding to the area containing the shallow areas 21b and 21d is relatively large.This determination of the depths of the non-continuous lamellar slot 21 and the compound lamellar slot 22 balances the stiffness distribution of the shoulder block 9 in the tire width direction. As a result, the ground contact pressure exerted on the shoulder block 9 can be balanced, especially when a front-to-back load acts on the shoulder block 9 in the tire circumferential direction. Accordingly, the wear resistance of the shoulder block 9 is ensured.

[0088] Other features of the tire according to the present embodiment include the following.

[0089] The tread area 2 contains a combination of the sipes, which include at least a portion with a corrugated shape (the corrugated sipes 15A, 15B, and 15C and the compound sipe 22), and the shoulder lateral groove 8 with the shoulder 8h. In particular, the shoulder block 9 contains the compound sipe 22 with the corrugated sipe area 22b. The sidewall 8d of the shoulder lateral groove 8, which delimits the shoulder block 9, contains the shoulder 8h on the surface side of the shoulder block 9. This arrangement creates a corner of the shoulder block 9. The corner, extending in the tire width direction, has two edges, namely the major edge 9a and the minor edge 9b. The compound lamellar slot 22 with the wavy lamellar slot area 22b, the main edge 9a, and the secondary edge 9b increase the total length of the edges contained in the shoulder block 9, which extend in the tire width direction.Accordingly, the ice and snow performance improves, i.e., traction and braking performance on icy and snowy roads are improved.

[0090] The corner of the shoulder block 9, extending in the direction of the tire width, has not just one edge, but two: the main edge 9a and the secondary edge 9b. This two-edge structure increases the resistance to deformation under a load acting on the corner of the shoulder block 9. Consequently, the stiffness of the shoulder block 9 is improved. With the improved stiffness of the shoulder block 9, steering stability on icy and snowy roads is enhanced, particularly steering stability during cornering.

[0091] The ground contact area of ​​the shoulder block 9 is not determined by the secondary edge 9b, but by the primary edge 9a, which lies within the secondary edge 9b in the tire radial view. Accordingly, the two-edge structure used here can reduce the ratio of the ground contact area to the volume of the shoulder block 9. Reducing the ground contact area increases the contact pressure of the shoulder block 9. Consequently, its performance on icy and snowy roads is improved.

[0092] The side wall 8d of the shoulder lateral groove 8 contains the shoulder 8h on the surface side of the shoulder block 9. In this case, a snow plug formed in the shoulder lateral groove 8 on a snow-covered road surface has a shape such that a proximal end is thicker than a distal end. Accordingly, the snow plug shear force is increased, and the vehicle's performance on snowy roads is improved.

[0093] With reference to Fig. 7 indicates the shoulder block 9 in one (by reference number 9c in Fig. The area designated 7, corresponding to the inner area 8a (with a relatively small width W5) of the shoulder lateral groove 8 in the tire width direction, has a relatively large width W10. The stiffness of the shoulder block 9 in zone 9c is relatively high, while the surface stiffness of the shoulder block 9 is relatively low. Here, "stiffness of the shoulder block" refers to the resistance to deformation not only of the surface of the shoulder block 9, but also of the solid body of the shoulder block 9. "Surface stiffness of the shoulder block" refers here to the resistance to deformation of the surface of the shoulder block 9.The inner region 8a of the shoulder lateral groove 8, where the preceding relationship between the stiffness of the shoulder block 9 and the surface stiffness of the shoulder block 9 applies, contains the straight lamellar slot region 22a of the compound lamellar slot 22, which produces such an effect as to maintain the surface stiffness of the shoulder block 9 more strongly than the stiffness of the shoulder block 9.

[0094] Shoulder block 9 has in one (identified by the reference number 9d in Fig. The area designated 7, corresponding to the outer area 8b (with a relatively large width W6) of the shoulder lateral groove 8 in the tire width direction, has a relatively small width W11. In zone 9d, the stiffness of the shoulder block 9 is relatively low, while the surface stiffness of the shoulder block 9 is relatively high. The outer area 8b of the shoulder lateral groove 8, where the preceding relationship between the stiffness of the shoulder block 9 and the surface stiffness of the shoulder block 9 applies, contains the corrugated lamellar slot area 22b of the compound lamellar slot 22, which has an effect of maintaining the stiffness of the shoulder block 9 more strongly than the surface stiffness of the shoulder block 9.

[0095] As described above, for the inner region 8a of the shoulder lateral groove 8 with the relatively small width W5 (where the shoulder block 9 has a relatively large width W10), the shoulder block 9 incorporates the straight lamellar slot region 22a of the compound lamellar slot 22. For the outer region 8b of the shoulder lateral groove 8 with the relatively large width W6 (where the shoulder block 9 has a relatively small width W11), the shoulder block 9 incorporates the wavy lamellar slot region 22b of the compound lamellar slot 22. This arrangement generates sufficient surface stiffness of the shoulder block 9 on the side of the center CL in the tire width direction (the side of the main shoulder groove 6) and thereby ensures advantageous ground contact of the shoulder block 9 and resulting favorable behavior on icy and snowy roads.Furthermore, sufficient block stiffness is achieved for the entire shoulder block 9, including the ground contact end GE of the shoulder block 9. Accordingly, advantageous steering stability on icy and snowy roads is ensured.

[0096] The center groove 11 and the straight lamellar slots 13A and 13B, located in the area opposite the center groove 11 in the tire width direction, are provided in the center rib 7. The side groove 12 and the straight lamellar slots 14A and 14B, located in the area opposite the side groove 12 in the tire width direction, are also provided in the center rib 7. The center groove 11, the side groove 12, and the straight lamellar slots 13A, 13B, 14A, and 14B thus create a large number of edges on the center rib 7. As a result, the ice and snow performance is improved, meaning that traction and braking performance on icy and snowy roads are enhanced.

[0097] The central rib 7 in the area opposite the central groove 11 in the tire width direction is smaller, i.e., narrower, than other areas. In this narrower area, no other grooves are provided, but rather the straight lamellar slots 13A and 13B. Accordingly, sufficient stiffness of the central rib 7 is maintained. Furthermore, the central rib 7 in the area opposite the side groove 12 in the tire width direction is narrow. In this narrower area, no other grooves are provided, but rather the straight lamellar slots 14A and 14B. Accordingly, sufficient stiffness of the central rib 7 is maintained. Therefore, advantageous steering stability is achieved on icy and snowy roads.Furthermore, the straight lamellar slots 13A, 13B, 14A and 14B, instead of notches provided in the central rib 7 in the narrower area opposite the central notch 11 and the side notch 12 in the tire width direction, compensate for the stiffness distribution of the central rib 7. Accordingly, resistance to uneven wear of the central rib 7 is ensured.

[0098] The angle θ4 of the straight sipes 13A and 13B with respect to the tire circumference has a different sign than the signs of the angles θ1 and θ2 of the center groove 11 with respect to the tire circumference. Accordingly, the imaginary line indicating the direction of extension of the center groove 11 and the imaginary lines indicating the directions of extension of the straight sipes 13A and 13B form a polygonal line, which in Fig. 4 projects upwards. The angle θ5 of the straight sipes 14A and 14B to the tire circumference direction has a different sign than the sign of the angle θ3 of the side groove 12 to the tire circumference direction. Accordingly, the imaginary line indicating the direction of extension of the side groove 12 and the imaginary lines indicating the directions of extension of the straight sipes 14A and 14B form a polygonal line which in Fig. 4 projects downwards. The polygonal arrangement of the central groove 11 and the straight lamellar slots 13A and 13B, and the polygonal arrangement of the side groove 12 and the straight lamellar slots 14A and 14B, improve the stiffness of the central rib 7 in the circumferential direction of the tire. Here, "rib stiffness" refers to the resistance to deformation not only of the rib's surface but also of the rib's solid body. An improvement in the stiffness of the central rib 7 in the circumferential direction of the tire increases steering stability on icy and snowy roads.

[0099] The polygonal arrangement of the central notch 11 and the straight lamellar slots 13A and 13B, and the polygonal arrangement of the side notch 12 and the straight lamellar slots 14A and 14B, also increase the overall length of the edges contained in the central rib 7. Consequently, the performance on icy and snowy roads is improved.

[0100] The imaginary line indicating the direction of extension of the central notch 11, and the imaginary lines indicating the directions of extension of the straight lamellar slots 13A and 13B, form a polygonal line which is in Fig. 4 projects upwards. On the other hand, the imaginary line indicating the direction of extension of the side notch 12 and the imaginary lines indicating the directions of extension of the straight lamella slots 14A and 14B form a polygonal line which in Fig. 4 projects downwards. The orientation of the former and the latter in opposite directions improves the stiffness of the central rib 7 even under a load acting on the central rib 7 in any direction around the tire's circumference. Consequently, steering stability on snowy and icy roads is further improved.

[0101] The straight sipes 13A and 13B, cited as examples of sipes provided in the area opposite the center groove 11 in the tire width direction, are sipes without a break point. Similarly, the straight sipes 14A and 14B, cited as examples of sipes provided in the area opposite the side groove 12 in the tire width direction, are sipes without a break point. The "break point" in the sipe refers here to a point where the direction of extension of the sipe changes in the tire radial direction. For example, if part of a sipe extends in one direction in the tire circumference direction and another part adjacent to it extends in the opposite direction in the tire circumference direction, a connecting region between these two parts is a break point.

[0102] In general, the surface stiffness of a rib containing a lamellar slot without a break point is higher than the surface stiffness of a rib containing a lamellar slot with a break point (e.g., a corrugated lamellar slot). Here, "surface stiffness of the rib" refers to the deformation resistance of the rib's surface. The straight lamellar slots 13A, 13B, 14A, and 14B, which are not lamellar slots with break points but rather lamellar slots without break points and which are advantageous with respect to surface stiffness, are provided in the area opposite the center groove 11 in the tire width direction and in the area opposite the side groove 12 in the tire width direction. This arrangement ensures advantageous ground contact of these parts and a resulting advantageous behavior on icy and snowy roads.

[0103] Another example of slotted louvers without a kink can be found in Fig. 12 circular arc lamellar slots 113A, 113B, 114A and 114B shown in the central rib 7 are provided instead of the straight lamellar slots 13A, 13B, 14A and 14B.

[0104] As in Fig. As shown in Figure 13, corrugated lamellar slots 213A, 213B, 214A and 214B can be provided in the central rib 7 instead of the straight lamellar slots 13A, 13B, 14A and 14B. This arrangement similarly ensures sufficient stiffness of the central rib 7 and compensates for the stiffness distribution of the central rib 7 by providing lamellar slots, rather than other notches, in the narrower areas opposite the central notch 11 and the side notch 12 in the tire width direction. List of reference symbols

[0105] 1: Tire, 2: Tread area, 3: Side area, 4: Shoulder area, 5: Central groove, 6; 6A; 6B: Shoulder groove, 7; 7A; 7B: Central rib, 8; 8A; 8B: Shoulder lateral groove, 8a: Inner area, 8b: Outer area, 8c: Bottom wall, 8d: Side wall, 8e: First area, 8f: Second area, 8g: Third area, 8h: Heel, 9; 9A; 9B: Shoulder block, 9a: Main edge, 9b: Secondary edge, 9c; 9d: Zone, 11: Central notch, 11a: Trunk area, 11b: Distal end area, 11c: Bottom area, 11d: Side area, 11e: First area, 11f: Second area, 11g: Third area, 11h: Heel, 11i: Main edge, 11j: Secondary edge, 12: Side notch, 12a: Bottom wall, 12b: Side wall, 12c: First area, 12d: Second area, 12e: Third area, 12f: Heel, 12g: Main edge, 12h: Secondary edge, 13A; 13B; 13C: Straight lamellar slot, 14A; 14B; 14C: Straight lamellar slot, 15A; 15B; 15C: wavy louver slot, 21: non-continuous louver slot, 21a; 21c; 21e: deep area, 21b;21d: flat area, 21f: flat groove, 21f; 21g; 21h: lamellar slot body area, 21i: side wall, 21j: bottom wall, 21k: side wall, 22: compound lamellar slot, 22a: straight lamellar slot area, 22b: corrugated lamellar slot area, 22c to 22g: area, 23: straight lamellar slot, 24: continuous projection area, 113A; 113B; 114A; 114B: circular arc lamellar slot, 213A; 213B; 214A; 214B: corrugated lamellar slot;

Claims

[1] Pneumatic tires (1), comprising: a central main groove (5) which is formed in a central zone of a tread area (2) in a tire width direction (TW) and extends in a tire circumferential direction (TC); a shoulder main groove (6, 6A, 6B) which is formed in the tread area (2) on one side of the ground contact end (GE, GE1, GE2) with respect to the central main groove (5) and extends in the tire circumferential direction (TC); a plurality of shoulder lateral grooves (8, 8A, 8B) formed in the tread area (2) extending in the tire width direction (TW), each having one end connected to the main shoulder groove (6, 6A, 6B) and another end terminating outside a ground contact end (GE, GE1, GE2) in the tire width direction (TW), and spaced apart in the tire circumferential direction (TC); a shoulder block (9, 9A, 9B) bounded by the main shoulder groove (6, 6A, 6B) and two shoulder lateral grooves (8, 8A, 8B) adjacent to each other in the circumferential direction (TC) of the plurality of shoulder lateral grooves (8, 8A, 8B); and a non-through lamellar slot (21) provided in the shoulder block (9, 9A, 9B), wherein the non-through lamellar slot (21) contains: a first deep area (21a) extending in the tire width direction (TW), one end which is connected to the main shoulder groove (6, 6A, 6B) and another end which is located in the shoulder block (9, 9A, 9B), and which includes a shallow groove (21f) and a first slat-slot body area (21f) the upper end of which is connected to a lower area of ​​the shallow groove (21f); a first shallow area (21b) extending in the tire width direction (TW) at a different angle (θ11) than an angle (θ8) of the first deep area (21a) to the tire width direction (TW), having one end connected to the first deep area (21a) and another end located in the shoulder block (9, 9A, 9B), and consisting of the same shallow groove (21f) as that (21f) of the first deep area (21a); ​​and a second deep area (21c) extending in the tire width direction (TW) at a different angle (θ9) than the angle (θ11) of the first flat area (21b) to the tire width direction (TW), offset in the tire circumferential direction (TC) relative to the first deep area (21a), having one end connected to the first flat area (21b) and another end located in the shoulder block (9, 9A, 9B), and containing the same flat groove (21f) as that (21f) of the first deep area (21a) and the first flat area (21b), and a second sipe body area (21g) whose upper end connects to a lower area of ​​the flat groove (21f), wherein a pair of side walls (21i) that bound the flat groove (21f) each have a chamfered shape in a sectional view perpendicular to an extension direction of the flat groove (21f), and the first deep area (21a), the first shallow area (21b) and the second deep area (21c) are each linear in tire radial view. [2] Pneumatic tire (1) according to claim 1, further comprising an additional lamellar slot (22) provided in the shoulder block (9, 9A, 9B) and arranged adjacent to the non-continuous lamellar slot (21) in the tire circumferential direction (TC), wherein the additional lamellar slot (22) includes a first area (22c) opposite the first deep area (21a) of the non-continuous lamellar slot (21) in the tire circumferential direction (TC), a second area (22d) opposite the first shallow area (21b) of the non-continuous lamellar slot (21) in the tire circumferential direction (TC), and a third area (22a) opposite the second deep area (21c) of the non-continuous lamellar slot (21) in the tire circumferential direction (TC), and a first depth of the first and third regions (22c, 22e) is smaller than a second depth of the second region (22d). [3] Pneumatic tire (1) according to claim 1 or 2, wherein the non-through lamellar slot (21) contains: a second shallow area (21d) extending in the tire width direction (TW) at a different angle (θ12) than the angle (θ19) of the second deep area (21c) to the tire width direction (TW), having one end connected to the second deep area (21c) and another end located in the shoulder block (9, 9A, 9B) and consisting of the same shallow groove (21f) as those of the first deep area (21a), the first shallow area (21b) and the second deep area (21c); and a third deep area (21e) extending in the tire width direction (TW) at a different angle (θ10) than the angle (θ12) of the second flat area (21d) to the tire width direction (TW), offset in the tire circumferential direction (TC) against the first deep area (21a) and the second deep area (21c), having one end connected to the first flat area (21b) and another end terminating in the shoulder block (9, 9A, 9B), containing the same flat groove (21f) as that of the first deep area (21a), the first flat area (21b), the second deep area (21c) and the second flat area (21d), and containing a third slat-slot body area (21h) the upper end of which connects to a lower area of ​​the flat groove (21f). [4] Pneumatic tires (1) according to claim 3, wherein each extends from the first deep area (21a), the second deep area (21c) and the third deep area (21e) at an angle (θ8, θ9, θ10) in a range from -20 degrees to 20 degrees to the tire width direction (TW), and an absolute value of the angle (θ11, θ12) formed by each of the first flat area (21b) and the second flat area (21d) to the tire width direction (TW) falls into a range of 2 degrees to 45 degrees. [5] Pneumatic tire (1) according to claim 3 or 4, wherein a depth (DE8) of the shallow groove (21f) falls within a range of 0.05 times to 0.5 times a depth (DE9) of the first deep area (21a), the second deep area (21c) and the third deep area (21e).

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