pneumatic tires

Abstract

We provide pneumatic tires that offer improved drainage compared to conventional tires. [Solution] The slit formed in the tread 2 includes a first slit 7 that extends continuously from the outer intermediate ridge 200 to the central ridge 100, the inner intermediate ridge 300, and the inner shoulder ridge 500. The first slit 7 has a first curved portion 7A that curves toward the other side C2 in the tire circumferential direction within the range from the outer intermediate ridge 200 through the central ridge 100 to the middle of the inner intermediate ridge 300, and a second curved portion 7B that curves toward the opposite side of the first curved portion 7A in the tire circumferential direction C, i.e., toward the other side C2 in the tire circumferential direction, within the range from the middle of the inner intermediate ridge 300 to the inner shoulder ridge 500.

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] Conventionally, pneumatic tires are known that include a tread having a plurality of main grooves extending in the tire circumferential direction and a plurality of lands extending in the tire circumferential direction between the main grooves, and various grooves are formed in the lands (see, for example, Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of tire, the drainage performance is improved by the main grooves, and the traction performance during rainy days and the like is ensured. In addition, drainage is also performed by grooves such as slits formed in the lands and extending in a direction intersecting the tire circumferential direction.

[0005] An object of the present invention is to provide a pneumatic tire with improved drainage performance compared to the prior art.

Means for Solving the Problems

[0006] The pneumatic tire of the present invention is a pneumatic tire comprising a tread including a plurality of landmasses extending in the circumferential direction of the tire and aligned in the axial direction of the tire, a plurality of main grooves between the plurality of landmasses, and slits formed in the landmasses, wherein the plurality of landmasses include a central landmass, a first intermediate landmass on one side of the central landmass in the axial direction of the tire, a second intermediate landmass on the other side of the central landmass in the axial direction of the tire, a first shoulder landmass on one side of the first intermediate landmass in the axial direction of the tire, and a second shoulder landmass on the other side of the second intermediate landmass in the axial direction of the tire, wherein the plurality of main grooves include a first central main groove between the central landmass and the first intermediate landmass, a second central main groove between the central landmass and the second intermediate landmass, and the first intermediate landmass The slit includes a first shoulder main groove between the first shoulder land and the second shoulder land, and a second shoulder main groove between the second intermediate land and the second shoulder land, the slit includes a first slit formed to extend continuously from the first intermediate land to the central land, the second intermediate land and the second shoulder land, the first slit having a first curved portion that curves to one side in the tire circumferential direction within the range from the first intermediate land through the central land to the middle of the second intermediate land, and a second curved portion that curves in the opposite direction to the first curved portion in the tire circumferential direction within the range from the middle of the second intermediate land to the second shoulder land. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a pneumatic tire with improved drainage performance compared to conventional tires. [Brief explanation of the drawing]

[0008] [Figure 1] This is a partially enlarged front view showing the tread surface of a tire according to an embodiment. [Figure 2] This is an enlarged view of the part shown in II in Figure 1. [Figure 3A] This is a cross-sectional view taken along the line IIIA-IIIA in Figure 2. [Figure 3B] This is a cross-sectional view of the IIIB-IIIB section in Figure 2. [Figure 3C] Figure 2 is a IIIC-IIIC cross-sectional view. [Figure 3D]It is a cross-sectional view taken along line III-D of FIG. 2. [Figure 4] It is a view corresponding to FIG. 2 and showing an example having a lowland portion in the enclosed area of the central land. [Figure 5A] It is a view corresponding to the V-V cross-section of FIG. 4 and showing an example of a lowland portion. [Figure 5B] It is a view corresponding to the V-V cross-section of FIG. 4 and showing another example of a lowland portion. [Figure 6] It is an enlarged view of the portion indicated by VI in FIG. 1. [Figure 7A] It is a cross-sectional view taken along line VII-A of FIG. 6. [Figure 7B] It is a cross-sectional view taken along line VII-B of FIG. 6. [Figure 7C] It is a cross-sectional view taken along line VII-C of FIG. 6. [Figure 7D] It is a cross-sectional view taken along line VII-D of FIG. 6. [Figure 8] It is an enlarged view of the portion indicated by VIII in FIG. 1. [Figure 9] It is an enlarged view of the portion indicated by IX in FIG. 1. [Figure 10A] It is a cross-sectional view taken along line X-A of FIG. 9. [Figure 10B] It is a cross-sectional view taken along line X-B of FIG. 9. [Figure 10C] It is a cross-sectional view taken along line X-C of FIG. 9. [Figure 10D] It is a cross-sectional view taken along line X-D of FIG. 9. [Figure 11A] It is a cross-sectional view taken along line XI-A of FIG. 9. [Figure 11B] It is a cross-sectional view taken along line XI-B of FIG. 9. [Figure 11C] It is a cross-sectional view taken along line XI-C of FIG. 9. [Figure 12] It is a diagram schematically showing a state of the outer shoulder size according to the embodiment as viewed from the side direction. [Figure 13A] It is a plan view schematically showing an opening on the tire surface of the outer shoulder size of the embodiment. [Figure 13B]A view corresponding to the XIIIB-XIIIB cross-section of FIG. 12, showing the outer shoulder size. [Figure 13C] A view corresponding to the XIIIC-XIIIC cross-section of FIG. 12, showing the outer shoulder size. [Figure 14A] A view corresponding to the XIVA-XIVA cross-section of FIG. 12, showing the outer shoulder size. [Figure 14B] A view corresponding to the XIVB-XIVB cross-section of FIG. 12, showing the outer shoulder size. [Figure 15] A view schematically showing the state of the corrugated shape portion of the inner shoulder size and the size bridge portion according to the embodiment as viewed from the side direction. [Figure 16A] A plan view schematically showing the opening of the inner shoulder size of the tire surface according to the embodiment. [Figure 16B] A view corresponding to the XVIB-XVIB cross-section of FIG. 15, showing the inner shoulder size. [Figure 17] A view corresponding to the XVII-XVII cross-sectional view of FIG. 15, showing the inner shoulder size.

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a partially enlarged front view of a tire 1 as a pneumatic tire according to an embodiment. FIG. 2 is an enlarged view of the portion indicated by II in FIG. 1 and shows a central land 100 described later. The tire 1 according to the embodiment is, for example, a pneumatic tire for a passenger car. Note that the configuration of the tire 1 according to the embodiment can be adopted for various vehicles such as light trucks, trucks, buses, etc. in addition to passenger cars.

[0010] Figure 1 shows the tire axis direction X, the tire circumferential direction C, and the tire equator E. The tire equator E is a hypothetical line extending from the center of the tire axis direction along the tire circumferential direction. In Figure 1, one side of the tire circumferential direction C (the lower side in Figure 1) is indicated by arrow C1, and the other side (the upper side in Figure 1) is indicated by arrow C2. The same symbols are used in Figures 2, 4, 6, and 7.

[0011] Figure 1 shows the tread 2 of the tire 1 according to the embodiment. The tread 2 includes a tread surface 2A which is the outer surface of the tire 1 and contacts the road surface. A tread pattern 3 consisting of multiple types of lines and grooves is formed on the tread surface 2A.

[0012] The grooves forming the tread pattern 3 include various main grooves, secondary grooves, slits, lug grooves, sipes, etc., as described later. The main grooves and secondary grooves are generally grooves that run along the circumferential direction of the tire, while the slits, lug grooves, and sipes are grooves that extend in a direction intersecting the circumferential direction of the tire. The width of these grooves is largest for the main grooves and smallest for the sipes. In the embodiment, the width of the various sipes is, for example, about 0.4 mm to 1.0 mm, and the depth is, for example, about 5 mm to 11 mm, but is not limited to these. The widths of the secondary grooves, slits, and lug grooves are all smaller than the main grooves and are the same as or larger than the sipes, but they may have similar widths or there may be differences.

[0013] The tread pattern 3 of this embodiment is asymmetrical in the tire axial direction. The tire 1 has a designated orientation for mounting on a vehicle, i.e., when mounted on a vehicle, with one side positioned on the outside in the vehicle width direction and the other on the inside in the vehicle width direction. The orientation for mounting on a vehicle is based on the tread pattern 3. In Figure 1, the outside in the vehicle width direction is indicated as "OUT" and the inside in the vehicle width direction is indicated as "IN". That is, in Figure 1, the right side of the paper is the outside in the vehicle width direction, and the left side of the paper is the inside in the vehicle width direction. In Figure 1, the tire axial direction X and the vehicle width direction are parallel. Figure 1 is a front view of the tire 1 when mounted on a vehicle, i.e., a front view of the tire 1 as seen from the front of the vehicle. The outside and inside in the vehicle width direction are similarly shown in Figures 2, 4, 6, 8, and 9.

[0014] As shown in Figure 1, the tire 1 of the embodiment is provided with sidewalls 9 extending radially toward a bead (not shown) on both sides of the tread 2 in the tire axial direction (direction toward the back of the paper in Figure 1). The sidewall 9 includes an outer sidewall 9A on the outside in the vehicle width direction and an inner sidewall 9B on the inside in the vehicle width direction.

[0015] The tread 2 comprises a plurality of ribs 5 arranged in the axial direction of the tire, and a plurality of main grooves 6 between the ribs 5. Each rib 5 is a rib-shaped protrusion extending in the circumferential direction of the tire. Each main groove 6 is a circumferential groove extending in the circumferential direction of the tire.

[0016] The multiple ground planes 5 include a central ground plane 100 positioned in the center of the tire axial direction, an outer intermediate ground plane 200 positioned outside the central ground plane 100 in the vehicle width direction, an inner intermediate ground plane 300 positioned inside the central ground plane 100 in the vehicle width direction, an outer shoulder ground plane 400 positioned outside the outer intermediate ground plane 200 in the vehicle width direction, and an inner shoulder ground plane 500 positioned inside the inner intermediate ground plane 300 in the vehicle width direction. The outer intermediate ground plane 200 is an example of the first intermediate ground plane of this disclosure, and the inner intermediate ground plane 300 is an example of the second intermediate ground plane of this disclosure. The outer shoulder ground plane 400 is an example of the first shoulder ground plane of this disclosure, and the inner shoulder ground plane 500 is an example of the second shoulder ground plane of this disclosure.

[0017] The widths of the three landforms 5, the central landform 100, the outer intermediate landform 200, and the inner intermediate landform 300, are, for example, between 18 mm and 50 mm, but are not limited to these widths.

[0018] In this embodiment, the widths of the three ridges 5, the central ridge 100, the outer intermediate ridge 200, and the inner intermediate ridge 300, are the same, but two of them may be the same and the others different, or all three may be different. In this embodiment, the widths of the outer shoulder ridge 400 and the inner shoulder ridge 500 are greater than the widths of the central ridge 100, the outer intermediate ridge 200, and the inner intermediate ridge 300. In this embodiment, the widths of the outer shoulder ridge 400 and the inner shoulder ridge 500 are the same, but they may be different.

[0019] The multiple main grooves 6 include an outer central main groove 600 between the central landform 100 and the outer intermediate landform 200, an inner central main groove 700 between the central landform 100 and the inner intermediate landform 300, an outer shoulder main groove 800 between the outer intermediate landform 200 and the outer shoulder landform 400, and an inner shoulder main groove 900 between the inner intermediate landform 300 and the inner shoulder landform 500. The outer central main groove 600 is an example of the first central main groove of this disclosure, and the inner central main groove 700 is an example of the second central main groove of this disclosure. The outer shoulder main groove 800 is an example of the first shoulder main groove of this disclosure, and the inner shoulder main groove 900 is an example of the second shoulder main groove of this disclosure. The width of each main groove 6 is, for example, about 4 mm to 18 mm, and the depth of each main groove 6 is, for example, about 8 mm to 13 mm, but is not limited thereto.

[0020] In this embodiment, the width of the outer central main groove 600 and the width of the inner central main groove 700 are the same. The width of the outer shoulder main groove 800 and the width of the inner shoulder main groove 900 are the same, and are slightly larger than the widths of the outer central main groove 600 and the inner central main groove 700. The widths of the outer central main groove 600 and the inner central main groove 700 are, for example, about 10% larger than the widths of the outer central main groove 600 and the inner central main groove 700.

[0021] The central rim 100 has a plurality of central sub-grooves 101 on its surface. The plurality of central sub-grooves 101 are arranged at intervals in the tire circumferential direction, approximately in the center of the width direction of the central rim.

[0022] The central sub-groove 101 includes a plurality of first sub-grooves 110 and a plurality of second sub-grooves 120. Both the first sub-grooves 110 and the second sub-grooves 120 extend linearly along the circumferential direction of the tire. The width of the first sub-grooves 110 and the second sub-grooves 120 is, for example, about 1 mm to 5 mm, and the depth is, for example, about 1 mm to 7 mm, but is not limited thereto.

[0023] As shown in Figure 2, the first sub-groove 110 is located on the outer side of the tire equator E in the vehicle width direction. The first sub-groove 110 has one end 111 on one side C1 in the tire circumferential direction and the other end 112 on the other side C2 in the tire circumferential direction. Both the one end 111 and the other end 112 are ends of the straight first sub-groove 110. Multiple first sub-grooves 110 are arranged at intervals in the tire circumferential direction.

[0024] The central land surface 100 has a first inclined groove 130. The first inclined groove 130 is an example of the second slit of this disclosure, which is substantially parallel to the first slit 7 described later and extends in a direction intersecting the tire circumferential direction C, with one end located inland. The width of the first inclined groove 130 is, for example, about 1.8 mm to 6 mm, and the depth is, for example, about 6 mm to 12 mm, but is not limited thereto.

[0025] The first inclined groove 130 extends from the other end 112 of the first sub-groove 110 toward the inner central main groove 700 and communicates with the inner central main groove 700. The first inclined groove 130 is inclined toward the other side C2 in the tire circumferential direction such that it forms an obtuse angle (91° or more) with the other end 112 of the first sub-groove 110. The other end 112 of the first sub-groove 110 communicates with the inner central main groove 700 via the first inclined groove 130. The first sub-groove 110 and the first inclined groove 130 form a continuous groove in a substantially inverted L shape.

[0026] Figure 3A is a cross-sectional view of Figure 2 taken along the line IIIA-IIIA. Figure 3B is a cross-sectional view of Figure 2 taken along the line IIIB-IIIB. Figure 3C is a cross-sectional view of Figure 2 taken along the line IIIC-IIIC. Figure 3D is a cross-sectional view of Figure 2 taken along the line IIID-IIID.

[0027] As shown in Figures 2 and 3A, the first sub-groove 110 includes a first narrow groove 113 and a first shelf 114 provided on one side of the first narrow groove 113 (in this case, the inner side in the vehicle width direction). The first narrow groove 113 is a groove having a width similar to that of the sipes in the embodiments described later. The first shelf 114 is shallower than the first narrow groove 113 and is formed in a stepped manner, communicating with the first narrow groove 113. The width of the first shelf 114 is approximately the same as the width of the first narrow groove 113, but is not limited to this.

[0028] As shown in Figures 2 and 3B, in the transition from the first sub-groove 110 to the first inclined groove 130, the width and depth of the first narrow groove 113 gradually increase, while the width of the first shelf 114 gradually decreases. As shown in Figure 2, the width of the first shelf 114 tapers as it transitions from the first sub-groove 110 to the first inclined groove 130, and it disappears when it reaches the first inclined groove 130. As the first shelf 114 disappears, the width of the first narrow groove 113 increases, and eventually the first narrow groove 113 connects to the first inclined groove 130 and disappears. Figure 3C shows a cross-section of the first inclined groove 130. As shown in Figure 3C, the first inclined groove 130 is wider and deeper than the first narrow groove 113.

[0029] Figure 3D shows a cross-section in the groove length direction at the transition from the first sub-groove 110 to the first inclined groove 130. As shown in Figure 3D, at the transition from the first sub-groove 110 to the first inclined groove 130, the depth of the first narrow groove 113 gradually increases, while the depth of the first shelf 114 gradually decreases. As the first shelf 114 disappears, the first narrow groove 113 disappears, becoming the depth of the first inclined groove 130.

[0030] The second sub-groove 120 is located inward in the vehicle width direction from the tire equator E and is adjacent to the first sub-groove 110 on the side of the inner central main groove 700. The second sub-groove 120 has one end 121 on one side C1 in the tire circumferential direction and the other end 122 on the other side C2 in the tire circumferential direction. Both the one end 121 and the other end 122 are the ends of the straight second sub-groove 120. Multiple second sub-grooves 120 are arranged at intervals in the tire circumferential direction. The second sub-groove 120 is shorter in the tire circumferential direction than the first sub-groove 110, and when viewed in the tire axial direction X, its total length overlaps with that of the first sub-groove 110. One end 121 of the second sub-groove 120 is located on the other side C2 in the tire circumferential direction than one end 111 of the first sub-groove 110.

[0031] The multiple central sub-grooves 101 of this embodiment, namely the first sub-groove 110 and the second sub-groove 120, are positioned to divide the central landmass 100 into approximately three equal parts in the width direction.

[0032] The central ridge 100 has a first sipe 150 that communicates with the inner central main groove 700 from the other end 122 of the second secondary groove 120. The first sipe 150 is approximately parallel to the first inclined groove 130. The width of the first sipe 150 is, for example, 0.6 mm to 1.2 mm, but is not limited thereto.

[0033] One end 111 of the first sub-groove 110 and one end 121 of the second sub-groove 120 are connected by a connecting groove 140. The connecting groove 140 allows the first sub-groove 110 and the second sub-groove 120 to communicate with each other. In this embodiment, the connecting groove 140 extends from one end 111 of the first sub-groove 110 to the other side C2 in the tire circumferential direction, curving convexly inward in the vehicle width direction, and connects to one end 121 of the second sub-groove 120. In this embodiment, the connecting groove 140 is configured to fold back from one end 111 of the first sub-groove 110 to the other side C2 in the tire circumferential direction, and the folded portion forms a substantially V-shaped groove with the first sub-groove 110 and the connecting groove 140. The width of the connecting groove 140 gradually decreases from one end 111 of the first sub-groove 110 to one end 121 of the second sub-groove 120.

[0034] The central landform 100 has an enclosed region 160 surrounded by grooves including at least the connecting groove 140 among the first sub-groove 110, the second sub-groove 120, and the connecting groove 140. In the embodiment, as shown in Figure 2, the central landform 100 has an enclosed region 160 surrounded by the first sub-groove 110 and the connecting groove 140. The enclosed region 160 has a tapered shape toward one side C1 in the circumferential direction of the tire.

[0035] Here, as shown in Figure 4, the tapered tip portion 161 of the enclosed region 160 may have a low land portion 162 in which the height of the land decreases in stages or gradually as it approaches one side C1 in the circumferential direction of the tire. Figure 4 is a diagram similar to Figure 2, showing an example in which the enclosed region 160 has a low land portion 162. Figures 5A and 5B show specific examples of the low land portion 162, respectively, and correspond to the VV cross-section in Figure 4.

[0036] The low land area 162 shown in Figure 5A is composed of steps 163, where the height of the land gradually decreases as you move towards the tip 161a of the enclosed area 160.

[0037] The low land area 162 shown in Figure 5B is composed of a tapered surface 164 in which the height of the land gradually decreases as it approaches the tip 161a of the enclosed area 160.

[0038] Because the enclosed area 160 has a low land portion 162, the enclosed area 160 is less likely to collapse or chip, and the rigidity of the land is easily ensured.

[0039] As shown in Figure 2, the central landmass 100 is provided with a first transverse slit 170. The width of the first transverse slit 170 is, for example, about 1.8 mm to 5 mm, and the depth is, for example, about 6 mm to 12 mm, but is not limited to these.

[0040] The first transverse slit 170 spans the first and second sub-grooves 110 and 120 of the central sub-groove 101, crosses the central land 100, and communicates with the outer central main groove 600 and the inner central main groove 700. That is, the outer central main groove 600 and the inner central main groove 700 are in communication via the first transverse slit 170. In this embodiment, the first transverse slit 170 is substantially parallel to the first inclined groove 130 and the first sipe 150. Furthermore, the width of the first transverse slit 170 is greater than the width of either the first sub-groove 110 or the second sub-groove 120.

[0041] As shown in Figures 1 and 2, the central ridge 100 is provided with a plurality of second sipes 180 that communicate with the outer central main groove 600. Each of the plurality of second sipes 180 is substantially parallel to the first inclined groove 130 and the first sipe 150, and is provided in a manner that extends along the extension of each first inclined groove 130. Therefore, the plurality of second sipes 180 are arranged in the tire circumferential direction at the same pitch as the plurality of first inclined grooves 130. One end of the second sipe 180 on the outer side in the vehicle width direction communicates with the outer central main groove 600, while the other end on the inner side in the vehicle width direction does not reach the first inclined groove 130 and terminates.

[0042] Figure 6 is an enlarged view of the portion shown as VI in Figure 1, and shows a part of the outer intermediate ridge 200. As shown in Figures 1 and 6, the outer intermediate ridge 200 has a plurality of third sub-grooves 210 on its surface that extend linearly along the tire circumferential direction. The plurality of third sub-grooves 210 are spaced apart in the tire circumferential direction. The width of the third sub-grooves 210 is, for example, about 1.6 mm to 4 mm, and the depth is, for example, about 1 mm to 5 mm, but is not limited thereto.

[0043] As shown in Figure 6, the third sub-groove 210 has one end 211 on one side C1 in the tire circumferential direction and the other end 212 on the other side C2 in the tire circumferential direction. Both the one end 211 and the other end 212 are ends of the straight third sub-groove 210. The third sub-groove 210 is offset slightly outward in the vehicle width direction (to the right in Figures 1 and 6) from the center in the width direction of the outer intermediate land 200.

[0044] The outer intermediate land area 200 includes a second inclined groove 220 and a third inclined groove 230. Each of the second inclined groove 220 and the third inclined groove 230 is an example of the second slit of this disclosure, extending in a direction substantially parallel to the first slit 7 described later and intersecting the tire circumferential direction C, with one end located inland. The width of the second inclined groove 220 and the third inclined groove 230 is, for example, about 2 mm to 6 mm, and the depth is, for example, about 6 mm to 12 mm, but is not limited thereto.

[0045] The second inclined groove 220 extends from one end 211 of the third sub-groove 210 toward the outer shoulder main groove 800 and communicates with the outer shoulder main groove 800. The second inclined groove 220 is inclined toward one side C1 in the circumferential direction of the tire such that it forms an obtuse angle (91° or more) with one end 211 of the third sub-groove 210.

[0046] The third inclined groove 230 extends from the other end 212 of the third sub-groove 210 toward the outer central main groove 600 and communicates with the outer central main groove 600. The third inclined groove 230 is inclined toward the other side C2 in the circumferential direction of the tire, forming an obtuse angle (91° or more) with the other end 212 of the third sub-groove 210.

[0047] The second inclined groove 220 and the third inclined groove 230 are approximately parallel to the first inclined groove 130. The third sub-groove 210, the second inclined groove 220, and the third inclined groove 230 form a series of grooves that can be described as roughly Z-shaped or crank-shaped.

[0048] Figure 7A is a cross-sectional view of Figure 6 from VIIA-VIIA. Figure 7B is a cross-sectional view of Figure 6 from VIIB-VIIB. Figure 7C is a cross-sectional view of Figure 6 from VIIC-VIIC. Figure 7D is a cross-sectional view of Figure 6 from VIID-VIID.

[0049] As shown in Figures 6 and 7A, the third sub-groove 210 includes a second narrow groove 213 and a second shelf 214 provided on one side of the second narrow groove 213 (in this case, the outer side in the vehicle width direction). The second narrow groove 213 is a groove having the same width as each sipe described later. The second shelf 214 is shallower than the second narrow groove 213 and is formed in a stepped manner, communicating with the second narrow groove 213. The width of the second shelf 214 is approximately the same as the width of the second narrow groove 213, but is not limited to this.

[0050] As shown in Figures 6 and 7B, in the section transitioning from the third sub-groove 210 to the third inclined groove 230, the width and depth of the second narrow groove 213 gradually increase, while the width of the second shelf 214 gradually decreases. As shown in Figure 6, the second shelf 214 tapers as it transitions from the third sub-groove 210 to the third inclined groove 230, and disappears when it reaches the third inclined groove 230. As the second shelf 214 disappears, the width of the second narrow groove 213 increases, and eventually the second narrow groove 213 connects to the third inclined groove 230 and disappears. Figure 7C shows a cross-section of the third inclined groove 230. As shown in Figure 7C, the third inclined groove 230 is wider and deeper than the second narrow groove 213.

[0051] Figure 7D shows a cross-section in the groove length direction at the transition from the third sub-groove 210 to the third inclined groove 230. As shown in Figure 7D, the depth of the second narrow groove 213 gradually increases at the transition from the third sub-groove 210 to the third inclined groove 230. Then, as the second shelf 214 disappears, the second narrow groove 213 disappears as it becomes the depth of the third inclined groove 230.

[0052] The transition from the third sub-groove 210 to the second inclined groove 220 is the same as described above.

[0053] The outer intermediate ridge 200 is provided with a plurality of first intermediate slits 240. One first intermediate slit 240 is provided in each third sub-groove 210. The width of the first intermediate slits 240 is, for example, about 1.8 mm to 5 mm, and the depth is, for example, about 5 mm to 11 mm, but is not limited thereto.

[0054] The first intermediate slit 240 starts midway along the length of the third sub-groove 210, extends outward in the vehicle width direction, and communicates with the outer shoulder main groove 800. The starting point of the first intermediate slit 240 is located slightly towards the other side C2 in the tire circumferential direction from the longitudinal center of the third sub-groove 210. The first intermediate slit 240 is inclined with respect to the tire circumferential direction at an angle nearly parallel to the second inclined groove 220.

[0055] As shown in Figure 6, the outer intermediate landmass 200 comprises a plurality of third sipes 251, a plurality of fourth sipes 252, a plurality of fifth sipes 253, and a plurality of sixth sipes 254. These sipes 251 to 254 are each spaced apart in the circumferential direction of the tire.

[0056] The third sipe 251 extends inward in the vehicle width direction, with a common starting point from the third sub-groove 210 in the first intermediate slit 240, and communicates with the outer central main groove 600. The third sipe 251 is slightly curved so as to be convex on one side C1 in the tire circumferential direction. The third sipe 251 is inclined with respect to the tire circumferential direction so as to be approximately parallel to the second inclined groove 220 and the third inclined groove 230. The third sipe 251 extends along approximately the extension of the first intermediate slit 240.

[0057] The fourth sipe 252 is located on the inner side in the vehicle width direction of the second inclined groove 220. The fourth sipe 252 extends along substantially the extension of the second inclined groove 220. The fourth sipe 252 is located between a pair of adjacent third sipes 251 in the tire circumferential direction, and is positioned substantially in the center between them. The fourth sipe 252 is substantially parallel to the third sipes 251 and is inclined with respect to the tire circumferential direction. One end of the fourth sipe 252 on the inner side in the vehicle width direction communicates with the outer central main groove 600, while the other end on the outer side in the vehicle width direction does not reach the second inclined groove 220 and terminates thereafter.

[0058] The fifth sipe 253 is located on the outer side in the vehicle width direction of the third sub-groove 210. In the tire circumferential direction C, the fifth sipe 253 is located between the second inclined groove 220 and the first intermediate slit 240, approximately in the center between them. The fifth sipe 253 is approximately parallel to the third sipe 251 and is inclined in the tire circumferential direction. One end of the fifth sipe 253 on the outer side in the vehicle width direction communicates with the outer shoulder main groove 800, while the other end on the inner side in the vehicle width direction does not reach the third sub-groove 210 and terminates there.

[0059] The sixth sipe 254 is located on the outer side in the vehicle width direction of the third inclined groove 230. The sixth sipe 254 extends along substantially the extension of the third inclined groove 230. The sixth sipe 254 is located between a pair of adjacent fifth sipes 253 in the tire circumferential direction, approximately in the center between them. The sixth sipe 254 is substantially parallel to the fifth sipe 253 and inclined with respect to the tire circumferential direction. One end of the sixth sipe 254 on the outer side in the vehicle width direction communicates with the outer shoulder main groove 800, while the other end on the outer-inside side in the vehicle width direction does not reach the third inclined groove 230 and terminates there.

[0060] As shown in Figure 6, the outer intermediate groove 200 further comprises a plurality of second intermediate slits 260 arranged at intervals in the tire circumferential direction C. The second intermediate slits 260 are located on the vehicle width side of the third sub-groove 210. The second intermediate slits 260 extend along substantially the extension of the fifth sipe 253. The second intermediate slits 260 are located in the tire circumferential direction C between the third sipe 251 and the fourth sipe 252, approximately in the center between them. The second intermediate slits 260 are substantially parallel to the first intermediate slit 240 and inclined in the tire circumferential direction C. One end of the second intermediate slit 260 on the vehicle width side communicates with the outer central main groove 600, while the other end on the vehicle width side terminates without reaching the third sub-groove 210. The second intermediate slit 260 gradually increases in width and depth as it moves from the end side towards the opening side to the outer central main groove 600.

[0061] The width of the second intermediate slit 260 is approximately 0.8 mm to 3 mm at its smallest end position and approximately 2 mm to 5 mm at its largest opening to the outer central main groove 600, but is not limited to these dimensions. The depth of the second intermediate slit 260 is approximately 1 mm to 3 mm at its shallowest end position and approximately 3 mm to 6 mm at its deepest opening to the outer central main groove 600, but is not limited to these dimensions.

[0062] Figure 8 is a magnified view of the area indicated by VIII in Figure 1. Figure 9 is a magnified view of the area indicated by IX in Figure 1.

[0063] As shown in Figures 8 and 9, the inner intermediate landmass 300 is provided with a plurality of inner intermediate slits 301.

[0064] The inner intermediate slit 301 includes a plurality of second transverse slits 310, a plurality of bend slits 320, and a plurality of third intermediate slits 330. Each of these slits 310, 320, and 330 is spaced apart in the tire circumferential direction C.

[0065] The second transverse slit 310 traverses the inner intermediate landform 300 and communicates with the inner central main groove 700 and the inner shoulder main groove 900. The second transverse slit 310 extends along the extension of the first transverse slit 170 of the central landform 100 and is inclined in the tire circumferential direction C in a manner that is substantially parallel to the first transverse slit 170. The width of the second transverse slit 310 is, for example, about 2 mm to 6 mm, and the depth is, for example, about 6 mm to 12 mm, but is not limited thereto.

[0066] As shown in Figure 9, the second transverse slit 310 has a first opening 310a that opens into the inner central main groove 700 and a second opening 310b that opens into the inner shoulder main groove 900. The width of the second transverse slit 310 gradually increases from the first opening 310a to the second opening 310b.

[0067] The bent slit 320 is formed in a bent shape from the inner central main groove 700 to the second transverse slit 310, connecting the inner central main groove 700 and the second transverse slit 310. The bent slit 320 of this embodiment has a straight portion 321 that extends linearly along the tire circumferential direction, and an inclined portion 322 that extends from one end C1 of the straight portion 321 toward the inner central main groove 700. The straight portion 321 is positioned approximately in the center in the width direction of the inner intermediate ridge 300 and is provided in such a manner that it penetrates the second transverse slit 310. The length C in the tire circumferential direction of the straight portion 321 of the bent slit 320 is longer than the length C in the tire circumferential direction of the third sub-groove 210 of the outer intermediate ridge 200. The inclined portion 322 has an opening 322a that communicates with the inner central main groove 700. The inclined portion 322 of the bent slit 320 is an example of a second slit of this disclosure that is substantially parallel to the first slit 7 described later and extends in a direction intersecting the tire circumferential direction C, with one end located inland.

[0068] The width of the straight section 321 is, for example, approximately 1 mm to 4 mm, and the depth is, for example, approximately 1 mm to 4 mm, but is not limited to these dimensions. The width of the inclined section 322 is, for example, approximately 2 mm to 6 mm, and the depth is, for example, approximately 6 mm to 12 mm, but is not limited to these dimensions.

[0069] As shown in Figure 8, the inclined portion 322 extends along the extension of the first inclined groove 130 of the central land 100 and is substantially parallel to the first inclined groove 130. That is, the inclined portion 322 intersects with the tire circumferential direction C and is inclined with respect to the tire circumferential direction C. The bent slit 320 of the embodiment has a substantially inverted L-shape overall.

[0070] The inner central main groove 700 has a groove-internal slit 710 provided in such a manner that it connects the second transverse slit 310 of the inner intermediate slit 301 with the first transverse slit 170 of the central land 100, and a protrusion 720 positioned between the inclined portion 322 of the bent slit 320 and the first inclined groove 130 of the central land 100.

[0071] Figure 10A is a cross-sectional view taken along line XA-XA in Figure 9. Figure 10B is a cross-sectional view taken along line XB-XB in Figure 9. Figure 10C is a cross-sectional view taken along line XC-XC in Figure 9. Figure 10D is a cross-sectional view taken along line XD-XD in Figure 9, showing a cross-section in the groove length direction at the point where the straight section 321 transitions to the inclined section 322.

[0072] As shown in Figures 10A to 10D, in the bent slit 320 of the embodiment, the depth of the inclined portion 322 shown in Figure 10C is greater than the depth of the straight portion 321 shown in Figure 10A. In the section transitioning from the straight portion 321 to the inclined portion 322, as shown in Figures 10C and 10D, the depth gradually increases from the straight portion 321 to the inclined portion 322, and the groove bottom is inclined.

[0073] The third intermediate slit 330 extends along approximately the extension of the inclined portion 322 of the bent slit 320. The third intermediate slit 330 is approximately parallel to the second transverse slit 310 and the inclined portion 322, and is inclined in the tire circumferential direction C. One end of the third intermediate slit 330 on the inner side in the vehicle width direction communicates with the inner shoulder main groove 900, while the other end on the outer side in the vehicle width direction does not reach the bent slit 320 and terminates. The width and depth of the third intermediate slit 330 gradually increase as it moves from the termination side toward the opening 330b toward the inner shoulder main groove 900.

[0074] The width of the third intermediate slit 330 is approximately 1 mm to 3 mm at its smallest end position and approximately 2 mm to 5 mm at its largest opening position to the outer central main groove 600, but is not limited to these dimensions. The depth of the third intermediate slit 330 is approximately 1 mm to 3 mm at its shallowest end position and approximately 5 mm to 10 mm at its deepest opening position to the outer central main groove 600, but is not limited to these dimensions.

[0075] Figure 11A is a cross-sectional view of Figure 9 from XIA-XIA. Figure 11B is a cross-sectional view of Figure 9 from XIB-XIB. Figure 11C is a cross-sectional view of Figure 9 from XIC-XIC.

[0076] As shown in Figures 11A to 11C, the third intermediate slit 330 communicates with the inner shoulder main groove 900, with its depth gradually increasing from the end towards the opening 330b.

[0077] Here, as shown in Figure 9, the sum of the widths 310aw of the first openings 310a of the multiple second transverse slits 310 for the inner central main groove 700 and the widths 322aw of the openings 322a of the inclined portions 322 of the multiple bent slits 320 for the entire tire 1 is defined as "(310aw × n1) + (322aw × n2)" = W1. Also, the sum of the widths 310bw of the second openings 310b of the multiple second transverse slits 310 for the inner shoulder main groove 900 for the entire tire 1 and the widths 330bw of the openings 330b of the multiple third intermediate slits 330 for the multiple third intermediate slits 330 for the entire tire 1 is defined as "(310bw × n1) + (330bw × n3)" = W2. n1 is the total number of multiple second transverse slits 310 provided in the tread 2, n2 is the total number of multiple bent slits 320 provided in the tread 2, and n3 is the total number of multiple third intermediate slits 330 provided in the tread 2.

[0078] In the tire 1 of the embodiment, W1 <W2である。

[0079] As shown in Figures 8 and 9, the inner intermediate landmass 300 further comprises a plurality of intermediate sipes 350.

[0080] Multiple intermediate sipes 350 are arranged in pairs in the tire circumferential direction C, between the second transverse slit 310 and the inclined portion 322 of the bend slit 320. The intermediate sipes 350 have a wave-like shape between their short, straight ends. Overall, the intermediate sipes 350 are approximately parallel to the second transverse slit 310. The intermediate sipes 350 intersect the straight portion 321 of the bend slit 320, traverse the inner intermediate ridge 300, and communicate with the inner central main groove 700 and the inner shoulder main groove 900.

[0081] As shown in Figure 1, the outer shoulder ramp 400 is positioned between the outer shoulder main groove 800 and the outer sidewall 9A. The outer end of the outer shoulder ramp 400 in the vehicle width direction is smoothly continuous with the outer sidewall 9A.

[0082] The outer shoulder 400 comprises a plurality of outer lug grooves 410, a plurality of outer slits 430, and a plurality of outer shoulder sipes 440, each of which is spaced apart in the circumferential direction of the tire.

[0083] The outer lug groove 410 extends from the outer radial end of the outer sidewall 9A toward the outer shoulder main groove 800 in a direction intersecting the tire circumferential direction C, and terminates without reaching the outer shoulder main groove 800. From the end of the outer lug groove 410, the outer slit 430 extends toward the outer shoulder main groove 800 and communicates with the outer shoulder main groove 800.

[0084] The outer lug groove 410 is slightly inclined toward one side C1 in the tire circumferential direction as it moves from the inside to the outside in the vehicle width direction, and is also slightly curved so as to be convex toward one side C1 in the tire circumferential direction. Furthermore, the width of the outer lug groove 410 gradually increases as it moves from the inside to the outside in the vehicle width direction, while the depth gradually decreases. The inner end of the outer lug groove 410 in the vehicle width direction tapers toward the outer slit 430.

[0085] The width of the outer slit 430 is smaller than and constant than the width of the outer lug groove 410. The outer slit 430 extends along the extension of the outer lug groove 410, along the edge of the outer lug groove 410 on the other side C2 in the tire circumferential direction.

[0086] The width of the outer lug groove 410 increases from approximately 1 mm to 3 mm at the inner end in the vehicle width direction towards the outer end in the vehicle width direction, to approximately 2 mm to 7 mm at the contact end. The depth of the outer lug groove 410 decreases from approximately 6 mm to 10 mm at the inner end in the vehicle width direction towards the outer end in the vehicle width direction, to approximately 0.5 mm to 2 mm.

[0087] The width of the outer slit 430 is, for example, about 1 mm to 3 mm, and the depth is, for example, about 2 mm to 5 mm, but is not limited to these dimensions.

[0088] An outer pattern groove 450 extending in the tire circumferential direction is provided on the outer side in the vehicle width direction of the outer shoulder 400. The outer pattern groove 450 extends substantially in the tire circumferential direction, passing through the outer ends in the vehicle width direction of a pair of adjacent outer lug grooves 410 in the tire circumferential direction.

[0089] A pair of outer shoulder sipes 440 are positioned between a pair of adjacent outer lug grooves 410 in the circumferential direction of the tire. One end of the outer shoulder sipe 440 on the inner side in the vehicle width direction communicates with the outer shoulder main groove 800, and from that end extends outward in the vehicle width direction in a direction intersecting the circumferential direction of the tire, terminating without reaching the outer pattern groove 450. The outer shoulder sipe 440 is slightly inclined toward one side C1 in the circumferential direction of the tire as it moves from the inner side to the outer side in the vehicle width direction, and is slightly curved so as to be convex toward one side C1 in the circumferential direction of the tire, so as to be approximately parallel to the outer lug grooves 410. The pair of outer shoulder sipes 440 positioned between the pair of outer lug grooves 410 divides the land between the pair of outer lug grooves 410 into approximately three equal parts in the circumferential direction of the tire.

[0090] As described above, the outer shoulder sipe 440 has a curved shape on the surface of the tire 1, i.e., the surface of the outer shoulder groove 400. This curved shape is a simple curve that traces a single arc from one end communicating with the outer shoulder main groove 800 to the outer end in the vehicle width direction, and there are no wave-like shapes, zigzag shapes, bent shapes, etc. between the one end and the end. The surface shape of the outer shoulder sipe 440 of the tire 1 may be a straight shape.

[0091] The outer shoulder sipe 440, as described above, has a simple curved shape on the tire surface, but is a 3D sipe that has a 3D shape in the depth direction. A 3D sipe, as used here, is a sipe that is not only three-dimensional due to bending in the direction of extension of the outer shoulder sipe 440 (the length direction from one end to the other as described above), but also has a part that bends in the depth direction, making it three-dimensional.

[0092] Figure 12 schematically shows the entire outer shoulder sipe 440 as viewed from the side. In this case, the side direction is the direction from one side C1 in the tire circumferential direction, and Figure 12 is an image of the entire inner wall surface of the outer shoulder sipe 440 on the other side C2 in the tire circumferential direction as viewed from that direction.

[0093] Figure 13A is a plan view showing the opening 449 of the outer shoulder sipe 440 on the tire surface. Figure 13B shows the XIIIB-XIIIB section of Figure 12. Figure 13C shows the XIIIC-XIIIC section of Figure 12. Figure 14A shows the XIVA-XIVA section of Figure 12. Figure 14B shows the XIVB-XIVB section of Figure 12. In Figures 13B, 13C, 14A, and 14B, only the outer shoulder sipe 440 is shown. As described above, the outer shoulder sipe 440 on the tire surface has a curved shape, and even inside the tire, this curved shape is generally reflected in the depth direction. However, in Figures 13A to 13C, the shape of the outer shoulder sipe 440 in the extending direction is simplified and shown as a straight line.

[0094] As shown in Figure 12, the outer shoulder sipe 440 has a surface layer 441 from the surface of the outer shoulder land 400 to a predetermined depth, which has no shape change in the extending direction and depth direction, forming a straight groove. In a predetermined portion excluding both sides in the extending direction, there is a corrugated shape portion 443 that extends from the surface layer 441 to the bottom 442, with a corrugated cross-sectional shape along the extending direction. Furthermore, the outer shoulder sipe 440 has a bent portion 444 where the corrugated shape bends in the approximately central part in the depth direction of the corrugated shape portion 443. The bent portion 444 includes a 3D sipe.

[0095] As shown in Figures 13B and 13C, the corrugated portion 443 has multiple valleys 443a extending in the depth direction, which are alternately formed on one side and the other side of the groove width along the extending direction of the outer shoulder sipe 440. The period and amplitude of the corrugated portion 443 formed by the multiple valleys 443a are both constant.

[0096] The multiple valleys 443a of the corrugated portion 443 are bent in a "V" shape in the depth direction when viewed from the tire circumferential direction, as shown in Figure 12, at the bent portion 444. Therefore, as shown in Figures 13B and 13C, the phase of the corrugated shape is shifted in the depth direction at the bent portion 444. Also, as shown in Figures 14A and 14B, the surface portion 441 of the outer shoulder sipe 440 includes an inclined portion 441a that slopes in the tire circumferential direction from the surface until it reaches the bent portion 444. The direction of inclination of the inclined portion 441a is staggered on one side and the other side of the groove width.

[0097] As shown in Figure 1, the inner shoulder ramp 500 is positioned between the inner shoulder main groove 900 and the inner sidewall 9B. The inner end of the inner shoulder ramp 500 in the vehicle width direction smoothly continues to the inner sidewall 9B.

[0098] The inner shoulder rim 500 comprises a plurality of first inner lug grooves 510, a plurality of second inner lug grooves 520, a plurality of inner slits 530, and a plurality of inner shoulder sipes 540, all of which are spaced apart in the circumferential direction of the tire.

[0099] The first inner lug groove 510 and the second inner lug groove 520 are arranged alternately at intervals in the circumferential direction of the tire.

[0100] The first inner lug groove 510 extends from the outer radial end of the inner sidewall 9B toward the inner shoulder main groove 900 in a direction intersecting the circumferential direction of the tire, and terminates without reaching the inner shoulder main groove 900. From the end of the first inner lug groove 510, the inner slit 530 extends toward the inner shoulder main groove 900 and communicates with the inner shoulder main groove 900.

[0101] The first inner lug groove 510 is slightly inclined toward the other side C2 in the tire circumferential direction as it moves from the outside in the vehicle width direction toward the inside, and is also slightly curved so as to be convex toward the other side C2 in the tire circumferential direction. The width of the first inner lug groove 510 is approximately constant, but the outer end in the vehicle width direction tapers toward the inner slit 530.

[0102] The width of the inner slit 530 is smaller than and constant than the width of the first inner lug groove 510. The inner slit 530 extends along the extension of the first inner lug groove 510, substantially aligned with the center line of the width of the first inner lug groove 510.

[0103] The second inner lug groove 520 is substantially the same as the first inner lug groove 510 and is parallel to the first inner lug groove 510, but communicates with the inner shoulder main groove 900. The second inner lug groove 520 is slightly inclined toward the other side C2 in the tire circumferential direction as it moves inward in the vehicle width direction from one end on the outer side in the vehicle width direction that communicates with the inner shoulder main groove 900, and is also slightly curved so as to be convex toward the other side C2 in the tire circumferential direction. The width of the second inner lug groove 520 is substantially constant, but its depth gradually decreases as it moves from the outer side in the vehicle width direction toward the inner side. The outer end of the second inner lug groove 520 in the vehicle width direction gradually narrows toward the inner shoulder main groove 900.

[0104] The width of the first inner lug groove 510 is, for example, about 2 mm to 7 mm at the contact end, but is not limited to this. The depth of the first inner lug groove 510 increases from, for example, about 0.5 mm to 2 mm to about 6 mm to 10 mm as you move from the outer end in the vehicle width direction to the inner end in the vehicle width direction.

[0105] The width of the inner slit 530 is, for example, approximately 1 mm to 3 mm, and the depth is, for example, approximately 2 mm to 5 mm, but is not limited to these dimensions.

[0106] An inner pattern groove 550 is provided on the inner side of the inner shoulder 500 in the vehicle width direction, extending in the tire circumferential direction. The inner pattern groove 550 extends substantially in the tire circumferential direction across the inner ends in the vehicle width direction of a pair of adjacent second inner lug grooves 520 in the tire circumferential direction. The inner pattern groove 550 penetrates the first inner lug groove 510 between the pair of second inner lug grooves 520.

[0107] A pair of inner shoulder sipes 540 are positioned between the first inner lug groove 510 and the second inner lug groove 520, which are adjacent in the circumferential direction of the tire. One end of the inner shoulder sipe 540, on the outer side in the vehicle width direction, communicates with the inner shoulder main groove 900, and from that end, it extends inward in the vehicle width direction in a direction intersecting the circumferential direction of the tire, terminating without reaching the inner pattern groove 550. The inner shoulder sipe 540 is slightly inclined towards the other side C2 in the circumferential direction of the tire as it moves from the outer side in the vehicle width direction to the inner side, and is slightly curved overall so as to be convex towards the other side C2 in the circumferential direction of the tire, so as to be approximately parallel to the first inner lug groove 510 and the second inner lug groove 520. The pair of inner shoulder sipes 540 positioned between the first inner lug groove 510 and the second inner lug groove 520 divides the land between the first inner lug groove 510 and the second inner lug groove 520 into approximately three equal parts in the circumferential direction of the tire.

[0108] As described above, the inner shoulder sipe 540 has an overall curved shape at the opening on the surface of the tire 1, i.e., the surface of the inner shoulder groove 500. However, as shown in Figure 1, a portion of it includes a wavy section in which the valleys of the wavy shape alternately continue in the direction of extension of the inner shoulder sipe 540. That is, as shown in Figure 1, the inner shoulder sipe 540 includes a wavy section 543, an inner extension 547 that extends substantially linearly inward in the vehicle width direction, continuous with the wavy section 543, and a sipe bridge 548 that extends substantially linearly outward in the vehicle width direction, continuous with the wavy section 543, and communicates with the inner shoulder main groove 900. The depth of the wavy section 543 is, for example, about 5 mm to 9 mm, but is not limited thereto. The depth of the sipe bridge 548 is, for example, about 1.5 mm to 4.0 mm, but is not limited thereto.

[0109] The inner shoulder sipe 540, like the outer shoulder sipe 440, includes a 3D sipe having a 3D shape in the depth direction.

[0110] Figure 15 schematically shows the corrugated portion 543 and the sipe bridge 548 of the inner shoulder sipe 540 as viewed from the side. In this case, the side direction is the direction from one side C1 in the tire circumferential direction, and Figure 15 is an image of the entire inner wall surface of the inner shoulder sipe 540 on the other side C2 in the tire circumferential direction as viewed from that direction.

[0111] Figure 16A is a plan view showing the corrugated portion 543 of the inner shoulder sipe 540 and the opening 549 of the sipe bridge 548 on the tire surface. The inner shoulder sipe 540 has a corrugated shape in the opening 549 on the tire surface. Figure 16B shows the XVIB-XVI section of Figure 15. Figure 17 shows the XVII-XVII section of Figure 15. Figures 16B and 17 show only the inner shoulder sipe 540. Similar to the outer shoulder sipe 440 shown in Figures 13A to 13C, the shape in the extending direction of Figures 16A and 16B is simplified and shown as a straight line.

[0112] The corrugated portion 543 of the inner shoulder sipe 540 is formed in a corrugated cross-sectional shape along the direction of extension, from the opening 549 to the bottom 542. The corrugated portion 543 has a bent portion 544 on the bottom 542 side of its approximate center in the depth direction. The bent portion 544 includes a 3D sipe.

[0113] As shown in Figure 15, the corrugated portion 543 has a first periodic portion 545 on the opening 549 side and a second periodic portion 546 on the bottom 542 side, with the boundary being approximately the center in the depth direction. The amplitude of the corrugated shape of the first periodic portion 545 and the corrugated shape of the second periodic portion 546 are approximately the same, but the period of the second periodic portion 546 is shorter than that of the first periodic portion 545. For example, the period of the second periodic portion 546 is approximately half that of the first periodic portion 545. In other words, the period of the corrugated shape of the corrugated portion 543 of the inner shoulder sipe 540 changes in the depth direction, becoming shorter as the depth increases.

[0114] The first periodic section 545 has a plurality of valleys 545a extending in the depth direction from the opening 549. The plurality of valleys 545a are formed alternately on one side and the other side of the groove width along the extending direction of the wave-shaped section 543. When the plurality of valleys 545a reach the bent section 544, they bend to one side in the extending direction of the first periodic section 545 (for example, inward in the vehicle width direction).

[0115] The second periodic section 546 has a plurality of valleys 546a extending from the bottom 542 in the direction of the opening 549. The plurality of valleys 546a are formed alternately on one side and the other side of the groove width along the extending direction of the wave-shaped section 543. When the plurality of valleys 546a reach the bend 544, they bend to the other side in the extending direction of the second periodic section 546 (for example, outward in the vehicle width direction). The width of the valleys 546a is approximately half the width of the valleys 545a of the first periodic section 545. This is because the period of the second periodic section 546 is approximately half the period of the first periodic section 545.

[0116] In the bent portion 544, the valley portion 545a of the first periodic portion 545 and the valley portion 546a of the second periodic portion 546 cause the sipe to bend in a "V" shape when viewed from the circumferential direction of the tire. In other words, in the bent portion 544, the period of the wave-shaped inner shoulder sipe 540 shifts from a long period in the first periodic portion 545 to a short period of approximately half in the second periodic portion 546.

[0117] As shown in Figure 17, the bent portion 544 includes an inclined portion 544a that is inclined to one side of the groove width in the depth direction.

[0118] In this embodiment, it is preferable that the depth of the outer shoulder sipe 440 of the outer shoulder ridge 400 and the depth of the inner shoulder sipe 540 of the inner shoulder ridge 500 have the following relationship. That is, it is preferable that the sipe length at a depth of 50% of the depth of each main groove of the outer shoulder sipe 440 approximates the sipe length at a depth of 50% of the depth of each main groove of the inner shoulder sipe 540, and for example, it is preferable that the approximation is within a range of ±10%. The sipe length referred to here is the total length in the direction of extension of the sipe, tracing the corrugated shape of the cross-section.

[0119] As shown in Figure 1, the second intermediate slit 260, the first transverse slit 170, the groove slit 710, the second transverse slit 310, and the second inner lug groove 520 are provided in a manner that they are continuous and inclined toward the other side C2 in the tire circumferential direction as they move from the inside to the outside in the vehicle width direction. Here, these second intermediate slit 260, the first transverse slit 170, the groove slit 710, the second transverse slit 310, and the second inner lug groove 520 are collectively referred to as the first slit 7. This first slit 7 is formed to extend continuously from the outer intermediate land area 200 to the central land area 100, the inner intermediate land area 300, and the inner shoulder land area 500.

[0120] The first slit 7 extends substantially parallel to the first inclined groove 130, the second inclined groove 220, the third inclined groove 230, and the inclined portion 322 of the bent slit 320, as described above.

[0121] The first slit 7 has a first curved portion 7A that curves convexly toward one side C1 in the tire circumferential direction, within a range from the outer intermediate land 200 through the central land 100 to the middle of the inner intermediate land 300. The first curved portion 7A curves so as it moves from the inside to the outside in the vehicle width direction, it curves toward the other side C2 in the tire circumferential direction. In this embodiment, this first curved portion 7A extends from the outer intermediate land 200 to a position on the inner shoulder main groove 900 side of the straight portion 321 of the bent slit 320 in the inner intermediate land 300.

[0122] Furthermore, the first slit 7 has a second curved portion 7B that curves convexly toward the opposite side of the first curved portion 7A, i.e., toward the other side C2 in the tire circumferential direction, within the range from the middle of the inner intermediate land 300 to the inner shoulder land 500. The second curved portion 7B curves so as it moves from the inside to the outside in the vehicle width direction, it curves toward the one side C1 in the tire circumferential direction. In this embodiment, the second curved portion 7B extends from a position on the inner shoulder main groove 900 side of the straight portion 321 of the bent slit 320 in the inner intermediate land 300, including the second inner lug groove 520.

[0123] As shown in Figure 8, the first curved section 7A and the second curved section are formed continuously via an inflection point 7C. This inflection point 7C is located midway along the width direction of the inner intermediate land 300, between the straight section 321 of the bent slit 320 and the inner shoulder main groove 900.

[0124] In this embodiment, the inner central main groove 700 has an internal groove slit 710, but it may not have this internal groove slit 710, and that portion may be the same depth as the inner central main groove 700. Alternatively, a protrusion may be formed instead of the internal groove slit 710. Also, the inner central main groove 700 has a protrusion 720, but it may not have this protrusion 720, and that portion may be the same depth as the inner central main groove 700. Alternatively, a slit may be formed instead of the protrusion 720.

[0125] The tire 1 of this embodiment has the above configuration. This tire 1 provides the following effects.

[0126] (1) The tire 1 according to the embodiment comprises a tread 2 including a plurality of ridges 5 extending in the circumferential direction C of the tire and aligned in the axial direction X of the tire, a plurality of main grooves 6 between the plurality of ridges 5, and slits formed in the ridges 5, the plurality of ridges 5 include a central ridge 100, an outer intermediate ridge 200 on one side of the central ridge 100 in the axial direction of the tire, an inner intermediate ridge 300 on the other side of the central ridge 100 in the axial direction of the tire, an outer shoulder ridge 400 on one side of the outer intermediate ridge 200 in the axial direction of the tire, and an inner shoulder ridge 500 on the other side of the inner intermediate ridge 300 in the axial direction, the plurality of main grooves 6 include an outer central main groove 600 between the central ridge 100 and the outer intermediate ridge 200, an inner central main groove 700 between the central ridge 100 and the inner intermediate ridge 300, and an outer shoulder groove 600 between the inner intermediate ridge 300 and the outer shoulder groove The slit includes an outer shoulder main groove 800 between the outer shoulder 400 and the inner shoulder main groove 900 between the inner intermediate shoulder 300 and the inner shoulder 500, and includes a first slit 7 formed to extend continuously from the outer intermediate shoulder 200 to the central shoulder 100, the inner intermediate shoulder 300 and the inner shoulder 500, and the first slit 7 has a first curved portion 7A that curves toward the other side C2 in the tire circumferential direction within the range from the outer intermediate shoulder 200 through the central shoulder 100 to the middle of the inner intermediate shoulder 300, and a second curved portion 7B that curves toward the opposite side of the first curved portion 7A in the tire circumferential direction C, i.e., toward the other side C2 in the tire circumferential direction within the range from the middle of the inner intermediate shoulder 300 to the inner shoulder 500.

[0127] According to the tire 1 of this embodiment, drainage is ensured at each land surface 5 where these slits and lug grooves are formed, by the second intermediate slit 260, the first transverse slit 170, the second transverse slit 310, and the second inner lug groove 520 that constitute the first slit 7. Drainage is guided in the order of the second intermediate slit 260, the first transverse slit 170, the groove slit 710, the second transverse slit 310, and the second inner lug groove 520, but since these extend continuously, drainage is smooth and drainage is ensured.

[0128] The first curved portion 7A of the first slit 7 allows for smooth drainage from near the axial center of the tire towards the inner intermediate land surface 300 when the tire is in contact with the ground, thereby improving drainage performance. Furthermore, the direction of drainage is changed to the second curved portion 7B, which is curved in the opposite direction to the first curved portion 7A, so that the drainage is directed toward the side of the tire (in the embodiment, toward the inside in the vehicle width direction), thereby improving drainage performance.

[0129] (2) In the tire 1 of the embodiment described in (1) above, the second slit has a first inclined groove 130 in the central land 100, a second inclined groove 220 and a third inclined groove 230 in the outer intermediate land 200, and an inclined portion 322 of the bent slit 320 in the inner intermediate land 300. This second slit is substantially parallel to the first slit 7 and extends in a direction intersecting the tire circumferential direction C, with one end located within the land 5.

[0130] As a result, each land surface 5 provided with a second slit has its rigidity ensured because one end of the second slit is located inside the land surface 5, compared to the case where one end is directly connected to the main groove 6. This ensured rigidity of the land surface 5 improves handling stability. Because the second slit is approximately parallel to the first slit 7, the reduction in rigidity of the land surface 5 is suppressed, thereby improving ground contact.

[0131] (3) In the tire 1 according to the embodiment described in (1) and (2) above, the first curved portion 7A and the second curved portion 7B are formed continuously via an inflection point 7C, and the inflection point 7C is located in the middle of the inner intermediate land 300.

[0132] As a result, the drainage flowing through the first slit 7 is redirected from the inner intermediate land 300 to the second curved section 7B via the inflection point 7C, thereby guiding the drainage inward in the vehicle width direction and improving drainage performance.

[0133] Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., made to the extent that the objectives of the present invention can be achieved are also included within the scope of the present invention. [Explanation of Symbols]

[0134] 1. Tire (pneumatic tire) 2 tread 5 land 6 Main groove 7. First Slit 7A First curved section 7B Second Curve Section 7C Inflection point 100 Chuo Riku 130 First inclined groove (second slit) 200 Outer intermediate land (first intermediate land) 220 Second inclined groove (second slit) 230 Third inclined groove (second slit) 300 Inner Intermediate Land (Second Intermediate Land) 322 Inclined portion of the bent slit (second slit) 400 Outer shoulder land (1st shoulder land) 500 Inner Shoulder (Second Shoulder) 600 Outer center main groove (1st center main groove) 700 Inner center main groove (2nd center main groove) 800 Outer shoulder main groove (first shoulder main groove) 900 Inner shoulder main groove (2nd shoulder main groove) C Tire circumferential direction X Tire Axle

Claims

1. A pneumatic tire having a tread including a plurality of landmasses extending in the circumferential direction of the tire and aligned in the axial direction of the tire, a plurality of main grooves between the plurality of landmasses, and slits formed in the landmasses, Multiple of the aforementioned landmasses are Central land and, The first intermediate land on one side of the tire axial direction of the central land, The second intermediate land on the other side of the tire axial direction of the aforementioned central land, The first shoulder land on one side of the tire axial direction of the first intermediate land, Including the second shoulder land on the other side of the tire axial direction of the second intermediate land, The multiple main grooves are, The first central main groove between the central land and the first intermediate land, The second central main trench between the central landmass and the second intermediate landmass, The first shoulder main groove between the first intermediate land and the first shoulder land, The second shoulder main groove between the second intermediate land and the second shoulder land, The slit includes a first slit formed to extend continuously from the first intermediate land to the central land, the second intermediate land, and the second shoulder land, A pneumatic tire wherein the first slit has a first curved portion that curves to either side in the tire circumferential direction within a range from the first intermediate land area through the central land area to the middle of the second intermediate land area, and a second curved portion that curves in the opposite direction to the first curved portion in the tire circumferential direction within a range from the middle of the second intermediate land area to the second shoulder land area.

2. The pneumatic tire according to claim 1, wherein the slit is provided in at least one of the central land, the first intermediate land, and the second intermediate land, and includes a second slit that is substantially parallel to the first slit and extends in a direction intersecting the tire circumferential direction, with one end of the slit located within the land.

3. The pneumatic tire according to claim 1 or 2, wherein the first curved portion and the second curved portion are formed continuously via an inflection point, and the inflection point is located in the middle of the second intermediate portion.

Images