JP5320172B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire including a plurality of land portions formed by main grooves extending along a tire circumferential direction, and the main grooves are provided on the inner side when the vehicle is mounted or on the outer side when the vehicle is mounted with respect to the tire equator line.

  Conventionally, a technique for suppressing the occurrence of hydroplaning in a pneumatic tire having a tread pattern asymmetric with respect to the tire equator line is known (see, for example, Patent Document 1). In this pneumatic tire, among the plurality of grooves forming the plurality of land portions, the position of the groove having the widest width in the tread width direction (hereinafter, thick groove) is deviated from the tire equator line (so-called offset).

  For example, in a vehicle in which a negative camber is set, the thick groove is disposed on the inner side than the tire equator line when the vehicle is mounted. For this reason, in a vehicle in which a negative camber is set, a thick groove is arranged near the center of the contact surface of the tread that is in contact with the road surface, so that the road surface and the tread are compared with the case where the thick groove is arranged on the tire equator line. Drainage performance for draining water that has entered between is improved. As a result, the occurrence of the above-described hydroplaning can be suppressed.

JP 2004-90763 A (page 1-2, FIG. 3)

  However, since the conventional pneumatic tire described above merely defines the position at which the thick groove is formed, there is a limit to improving drainage performance, and a technique for further improving drainage performance is required. It was.

  Therefore, an object of the present invention is to provide a pneumatic tire that can improve the drainage performance more reliably when mounted on a vehicle having a camber angle such as a negative camber.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention includes a plurality of land portions (land portions 20) formed by main grooves (for example, main grooves 12) extending along the tire circumferential direction, and the main grooves are the tire equator. A pneumatic tire (for example, pneumatic tire 1) provided on the inner side when the vehicle is mounted (inner side when the vehicle is mounted) or on the outer side when the vehicle is mounted (outer side when the vehicle is mounted) with respect to the line (tire equator line CL) The land portion includes a first land portion (land portion 22) having a first groove wall (groove wall 22A) that forms one wall surface of the main groove, and a second land portion that forms the other wall surface of the main groove. A second land portion (land portion 23) having a groove wall (groove wall 23A), the first groove wall and the second groove wall meander along the tire circumferential direction in a tread surface view, At least one of the first land portion or the second land portion extends in the tread width direction. Groove (dividing lug groove 40A2 or dividing lug groove 40A3) is formed, and the groove width (groove width W) of the main groove along the tread width direction is a predetermined repetition period (period λ) along the tire circumferential direction. ) To change.

  According to such a feature, the first groove wall and the second groove wall meander along the tire circumferential direction in a tread surface view, and the groove width of the main groove along the tread width direction is along the tire circumferential direction. It changes at a predetermined cycle. According to this, the flow of water along the meandering of the first groove wall and the second groove wall is generated in the main groove. The water flowing in the main groove pulsates at a predetermined cycle, and is drained in the direction of the streamline extension along the first groove wall and the second groove wall from the wide groove width portion to the narrow groove portion. It becomes easy. Accordingly, the drainage performance for draining water that has entered between the road surface and the tread can be improved more reliably.

  Further, the main groove described above is provided on the inner side when the vehicle is mounted or on the outer side when the vehicle is mounted with respect to the tire equator line. According to this, when mounted on a vehicle with a set camber angle, the main groove is disposed in the vicinity of the center of the contact surface of the tread that contacts the road surface. For this reason, compared with the case where a main groove is arrange | positioned on a tire equator line, drainage performance can be improved further reliably.

  Furthermore, the lug groove is formed in at least one of the first land portion or the second land portion. According to this, the water between the tread tread (land surface) and the road surface flows into the lug groove and is easily discharged to the outside in the tread width direction as compared with the case where the lug groove is not formed. Accordingly, the drainage performance can be improved more reliably.

  Thus, since drainage performance can be improved reliably, the occurrence of hydroplaning can be suppressed as a result.

A second feature of the present invention relates to the first feature of the present invention, wherein the ratio W _MIN / W _MAX between the minimum width portion W _MIN of the groove width and the maximum width portion W _MAX of the groove width is 35 The gist is that it is in the range of% to 85%.

A third feature of the present invention relates to the first or second feature of the present invention, wherein the main groove is provided with a wide groove portion (wide portion 12A) including a maximum width portion W _MAX of the groove width, The lug groove is inclined with respect to the tire circumferential direction, and is summarized as being in communication with or close to the wide groove portion.

  A fourth feature of the present invention relates to the third feature of the present invention, wherein a distance from the tire equator line to the main groove is 9 with respect to a tread ground contact width (tread ground contact width TW) in the tread width direction. The gist is that it is ˜25%.

  A fifth feature of the present invention relates to the first to fourth features of the present invention, wherein the first groove wall and the second groove wall have a predetermined amplitude (amplitude a) along the tread width direction. And the predetermined repetition period is 15 to 100 times the predetermined amplitude.

A sixth feature of the present invention relates to the first to fifth features of the present invention, wherein the main groove is provided with a wide groove portion including the maximum width portion _WMAX, and the bottom portion (bottom portion 12F) of the main groove. The gist is that a bulge portion (bulge portion 30) that bulges outward in the tire radial direction is formed, and the bulge portion is formed in the wide groove portion.

  A seventh feature of the present invention relates to the sixth feature of the present invention, wherein a first side portion (side portion 30c) of the raised portion facing the first groove wall is along the first groove wall. The gist is that the second side portion (side portion 30d) of the raised portion that extends and faces the second groove wall extends along the second groove wall.

  An eighth feature of the present invention relates to the seventh feature of the present invention, wherein the raised portion is formed on a front end portion (front end 30a) and a rear end portion (rear end 30b) of the raised portion in the tread surface view. The gist is that it gets thinner as you go.

  A ninth feature of the present invention relates to the sixth to eighth features of the present invention, wherein a height (height H) of the raised portion is less than a depth (depth D) of the main groove. The gist.

  According to the features of the present invention, it is possible to provide a pneumatic tire that can improve drainage performance more reliably when mounted on a vehicle having a camber angle such as a negative camber.

FIG. 1 is a development view showing a tread pattern of the pneumatic tire 1 according to the first embodiment. FIG. 2 is an expanded view of the vicinity of the main groove 12 according to the first embodiment. FIG. 3 is a partial cross-sectional perspective view showing the vicinity of the main groove 12 according to the first embodiment. 4 is a cross-sectional view (a cross-sectional view taken along the line AA in FIG. 3) showing the vicinity of the main groove 12 according to the first embodiment. FIG. 5 is a development view showing a tread pattern of the pneumatic tire 1A according to the second embodiment. FIG. 6 is an expanded view of the vicinity of the main groove 12 according to the first embodiment.

  Next, an embodiment of a pneumatic tire according to the present invention will be described with reference to the drawings. Specifically, the first embodiment, the second embodiment, comparative evaluation, and other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First Embodiment]
The pneumatic tire according to the first embodiment will be described below with reference to the drawings. Specifically, (1.1) configuration of pneumatic tire, (1.2) configuration of main groove, (1.3) configuration of raised portion, (1.4) configuration of lug groove, (1.5 ) Explain the action and effect.

(1.1) Configuration of Pneumatic Tire First, the configuration of the pneumatic tire 1 according to the first embodiment will be described with reference to the drawings. FIG. 1 is a development view showing a tread pattern of the pneumatic tire 1 according to the first embodiment. In the pneumatic tire 1, the tread contact width TW with respect to the tread width direction is 215 mm or more.

  As shown in FIG. 1, the pneumatic tire 1 includes a plurality of land portions 20 formed by a plurality of main grooves 10 extending along the tire circumferential direction. Specifically, the plurality of main grooves 10 include a main groove 11, a main groove 12, and a main groove 13 from the inner side IN (left side in FIG. 1) when the vehicle is mounted to the outer side OUT (right side in FIG. 1) when the vehicle is mounted. It is comprised by.

  The main groove 11 extends linearly along the tire circumferential direction. The main groove 11 is provided on the inner side IN when the vehicle is mounted with respect to the tire equator line CL.

  The main groove 12 is a groove that contributes most to the drainage performance among the plurality of main grooves 10. The main groove 12 extends while the groove width W along the tread width direction changes along the tire circumferential direction. A raised portion 30 is formed on the bottom portion 12F of the main groove 12 so as to protrude outward in the tire radial direction.

  The main groove 12 is provided on the inner side IN when the vehicle is mounted with respect to the tire equator line CL. The distance D (offset amount) from the tire equator line CL to the main groove 12 is 9 to 25% with respect to the tread contact width TW in the tread width direction. The configuration of the main groove 12 and the raised portion 30 will be described later.

  The main groove 13 extends linearly along the tire circumferential direction. The main groove 13 extends while the groove width W along the tread width direction changes along the tire circumferential direction due to the shape of a land portion 23 and a land portion 24 described later. The main groove 13 is provided on the outer side OUT when the vehicle is mounted with respect to the tire equator line CL.

  The land portion 20 includes a land portion 21, a land portion 22, a land portion 23, and a land portion 24 from the inner side IN when the vehicle is mounted to the outer side OUT when the vehicle is mounted.

  The land portion 21 is formed on the inner side IN when the vehicle is mounted than the main groove 11. The land portion 22 is formed by the main groove 11 and the main groove 12. The land portion 23 is formed by the main groove 12 and the main groove 13. The land portion 24 is formed outside the main groove 13 when the vehicle is mounted.

  A lug groove 40 extending in the tread width direction is formed in the land portion 20 (land portion 21 to land portion 24). The configuration of the lug groove 40 will be described later.

(1.2) Structure of main groove Among the main grooves 11 to 13 described above, the structure of the main groove 12 will be described with reference to the drawings. Specifically, (1.2.1) the groove wall forming the main groove 12 and (1.2.2) the groove width W of the main groove 12 will be described. FIG. 2 is an expanded view of the vicinity of the main groove 12 according to the first embodiment.

(1.2.1) Groove Wall Forming Main Groove 12 As shown in FIGS. 1 and 2, the land portion 22 (first land portion) located on the inner side IN when the vehicle is mounted on the main groove 12 is the main groove. 12 has a groove wall 22A (first groove wall) forming one of the wall surfaces. The land portion 23 (second land portion) located on the outer side OUT when the main groove 12 is mounted on the vehicle has a groove wall 23 </ b> A (second groove wall) that forms one wall surface of the main groove 12.

  The groove wall 22A and the groove wall 23A meander along the tire circumferential direction in the tread surface view. The groove wall 22A and the groove wall 23A are provided symmetrically with respect to the main groove center line DC extending along the tire circumferential direction through the center of the main groove 12 with respect to the tread width direction.

(1.2.2) Amplitude and Period of Main Groove 12 As shown in FIGS. 1 and 2, the groove width W of the main groove 12 along the tread width direction is a predetermined repetition period along the tire circumferential direction. Change. The groove width W of the main groove 12 indicates a distance in the tread width direction from an arbitrary point on the groove wall 22A to the groove wall 23A.

The main groove 12 is provided with a wide portion 12A and a narrow portion 12B. The wide portion 12A includes a maximum width portion W _MAX of the groove width W of the main groove 12 along the tread width direction. On the other hand, the narrow portion 12B includes a minimum width portion W _MIN of the groove width W of the main groove 12 along the tread width direction. The wide portions 12A and the narrow portions 12B are alternately provided in the tire circumferential direction.

The ratio W _MIN / W _MAX between the minimum width portion W _MIN of the groove width W of the narrow portion 12B and the maximum width portion W _MAX of the groove width W of the wide portion 12A is in the range of 35% to 85%.

The groove wall 22A and the groove wall 23A have a predetermined amplitude a along the tread width direction. The groove wall 22A and the groove wall 23A change with a period λ along the tire circumferential direction in the tread surface view. Groove wall 22A and the groove wall 23A, when the minimum width portion W _MIN and the starting point of the period lambda, the boundary of the maximum width portion W _MAX, is formed in a shape symmetrical with the tire rotation direction forward and backward.

  The period λ in the tire circumferential direction of the groove wall 22A and the groove wall 23A is 15 to 100 times the amplitude a. Further, the tread length in the tire circumferential direction of the tread that contacts the road surface during rolling of the tire is 0.5 to 20 times the period λ of the main groove 12.

(1.3) Configuration of Raised Part Next, the configuration of the raised part 30 according to the first embodiment will be described with reference to FIGS. FIG. 3 is a partial cross-sectional perspective view showing the vicinity of the main groove 12 according to the first embodiment. FIG. 4 is a cross-sectional view (cross-sectional view taken along the line AA in FIG. 3) showing the vicinity of the main groove 12 according to the first embodiment.

  As shown in FIGS. 1-4, the protruding part 30 is formed in the wide part 12A. The raised portion 30 is formed in a vertically long shape along the tire circumferential direction in the tread surface view.

  In the tread surface view, the raised portion 30 becomes narrower as it goes to the front end 30a (front end portion) forward in the tire rotation direction and the rear end 30b (rear end portion) rearward in the tire rotation direction. Further, the side portion 30c (first side portion) of the raised portion 30 facing the groove wall 22A extends along the groove wall 22A. Further, the side portion 30d (second side portion) of the raised portion 30 facing the groove wall 23A extends along the groove wall 23A.

  The raised portions 30 are provided symmetrically about the main groove center line DC in the tread surface view. The height H of the raised portion 30 is preferably less than the depth D of the main groove 12.

(1.4) Configuration of Lug Groove Next, the configuration of the lug groove 40 according to the first embodiment will be described with reference to FIG. As shown in FIG. 1, the lug groove 40 is constituted by a divided lug groove 40A and a terminal lug groove 40B. The split lug groove 40A and the terminal lug groove 40B are inclined with respect to the tire circumferential direction and extend outward in the tread width direction toward the rear in the tire rotation direction. The divided lug groove 40A and the terminal lug groove 40B extend in a curved state from the front to the rear in the tire rotation direction.

  The dividing lug groove 40 </ b> A divides the land portion 20 in the tread width direction and communicates with the main groove 10. The divided lug grooves 40A are formed in the divided lug groove 40A1 formed in the land portion 21, the divided lug groove 40A2 formed in the land portion 22, the divided lug groove 40A3 formed in the land portion 23, and the land portion 24. And the divided lug groove 40A4.

  At least one end of the terminal lug groove 40B ends in the land portion 20. The terminal lug groove 40B includes a terminal lug groove 40B2 formed in the land portion 22, a terminal lug groove 40B3 formed in the land portion 23, and a terminal lug groove 40B4 formed in the land portion 24. The land portion 21 is not formed with the terminal lug groove 40B.

Here, the divided lug groove 40A2 and the divided lug groove 40A3 communicate with the wide portion 12A. In particular, one of the dividing lug grooves 40A2 and dividing lug grooves 40A3 from groove wall 22A and the groove wall 23A to form the minimum width portion W _MIN of the groove width of the narrow portion 12B, the groove width of the wide portion 12A top it is preferably provided on the extension EX along the groove wall 22A and the groove wall 23A to form a substantial portion W _MAX. The dividing lug groove 40A2 and the dividing lug groove 40A3 are provided asymmetrically with respect to the main groove center line DC in order to reduce noise.

  The dividing lug groove 40A1 is provided along the extension line S1 along the extending direction of the dividing lug groove 40A2. Moreover, the dividing lug groove 40A4 is provided along the extension line S2 along the extending direction of the dividing lug groove 40A3.

  The terminal lug groove 40B2 is provided between the divided lug grooves 40A2 adjacent to the tire circumferential direction. The terminal lug groove 40B1 is provided along the extension line T1 along the extending direction of the terminal lug groove 40B2. The terminal lug groove 40B3 is provided between the divided lug grooves 40A3 adjacent to the tire circumferential direction. The terminal lug groove 40B4 is provided along the extension line T2 along the extending direction of the terminal lug groove 40B3.

(1.5) Action / Effect In the first embodiment described above, the groove wall 22A and the groove wall 23A meander along the tire circumferential direction in the tread surface view, and the groove width W of the main groove 12 is equal to the tire width. It changes with a predetermined period λ along the circumferential direction. According to this, in the main groove | channel 12, the flow of the water along the meandering of the groove wall 22A and the groove wall 23A generate | occur | produces. Water flowing through the main groove 12 is pulsating at a predetermined cycle lambda, it is drained to the extension direction of the streamlines along the groove wall 22A and the groove wall 23A towards the widest part W _MAX to the minimum width portion W _MIN It becomes easy. Accordingly, the drainage performance for draining water that has entered between the road surface and the tread can be improved more reliably.

  The main groove 12 is provided on the inner side IN when the vehicle is mounted with respect to the tire equator line CL. According to this, when the negative camber is mounted on the vehicle, the main groove 12 is disposed in the vicinity of the center of the contact surface of the tread that is in contact with the road surface. For this reason, compared with the case where the main groove 12 is arrange | positioned on the tire equator line CL, drainage performance can be improved more reliably.

  Furthermore, the lug groove 40 is formed in at least one of the land portion 22 or the land portion 23. According to this, water between the tread tread (the surface of the land portion 22 or the land portion 23) and the road surface flows into the lug groove 40, and on the outer side in the tread width direction compared to the case where the lug groove is not formed. It becomes easy to be discharged. In particular, the lug groove 40 communicates with the main groove 12 so that the lug groove 40 is more reliably discharged to the outer side in the tread width direction. Accordingly, the drainage performance can be improved more reliably.

  Thus, since drainage performance can be improved reliably, the occurrence of hydroplaning can be suppressed as a result.

In the first embodiment, the ratio W _MIN / W _MAX between the minimum width portion W _MIN of the groove width W of the main groove 12 and the maximum width portion W _MAX of the groove width W of the main groove 12 is 35% to 85%. It is a range. According to this, the water flowing along the groove wall 22A and the groove wall 23A after passing through the widest part W _MAX, with decreasing the groove width W of the main groove 12, the groove wall 22A and a minimum width portion W _MIN It becomes easier to drain in the direction of the extension of the streamline along the groove wall 23A. That is, the water in the main groove tends to go outward in the tread width direction. Therefore, drainage performance can be improved more reliably.

When the ratio W _MIN / W _MAX is 35% or more, the water flow along the groove wall 22A and the groove wall 23A at the minimum width portion W _MIN and the water flow along the tire circumferential direction are excessive. Without concentrating, the decline in drainage performance can be more reliably suppressed. On the other hand, when the ratio W _MIN / W _MAX is 85% or less, the water in the main groove 12 tends to pulsate, and the drainage performance can be improved more reliably.

In the first embodiment, the lug grooves 40 (the divided lug grooves 40A2 and the divided lug grooves 40A3) communicate with the wide portion 12A. According to this, the water flowing along the groove wall 22A and the groove wall 23A after passing through the widest part W _MAX, with decreasing the groove width W of the main groove 12, the groove wall 22A and a minimum width portion W _MIN It becomes easier to drain in the direction of the extension of the streamline along the groove wall 23A. That is, the water in the main groove 12 tends to go outward in the tread width direction.

  In the first embodiment, the distance D (offset amount) from the tire equator line CL to the main groove 12 is 9 to 25% with respect to the tread ground contact width TW in the tread width direction. According to this, the main groove 12 can be disposed in the vicinity of the center of the ground contact surface of the tread in contact with the road surface so as to correspond to various camber angle settings. For this reason, the pneumatic tire 1 corresponding to various camber angles can be manufactured.

  In addition, when the distance D is 9% or more and 25% or less with respect to the tread contact width TW, the main groove 12 is disposed in the vicinity of the center of the contact surface of the tread that is in contact with the road surface when the camber angle is set. It becomes easy to suppress the decrease in drainage performance.

  In the first embodiment, the period λ is 15 to 100 times the amplitude a. According to this, since the water flowing in the main groove 12 can be effectively drained to the outside of the main groove 12, the drainage performance can be improved more reliably.

In addition, when the period λ is 15 times or more of the amplitude a, the water flow along the groove wall 22A and the groove wall 23A and the water flow along the tire circumferential direction are excessive at the minimum width portion W _MIN. Concentration can be sufficiently suppressed. On the other hand, when the period λ is 100 times the amplitude a or less, the water in the main groove 12 can sufficiently pulsate, and the water flowing in the main groove 12 is effectively drained to the outside of the main groove 12. it can.

  In the first embodiment, a raised portion 30 that protrudes outward in the tire radial direction is formed on the bottom portion 12F of the wide portion 12A of the main groove 12. According to this, the water flowing in the wide portion 12A is likely to flow along the groove wall 22A and the groove wall 23A by the raised portion 30. That is, the water flowing in the wide portion 12A is easily drained into the lug groove 40 (the divided lug groove 40A2 and the divided lug groove 40A3) by the raised portion 30. For this reason, the water which flows in the wide part 12A can be drained efficiently, and drainage performance can be improved more reliably. .

  In the first embodiment, the side portion 30c of the raised portion 30 that faces the groove wall 22A extends along the groove wall 22A, and the side portion 30c of the raised portion 30 that faces the groove wall 23A extends along the groove wall 23A. Extend. According to this, the water flowing in the wide portion 12A becomes easier to flow along the groove wall 22A and the groove wall 23A.

  In the first embodiment, the protruding portion 30 becomes narrower as it goes to the front end 30a in the tire rotation direction front and the rear end 30b in the tire rotation direction rear in the tread surface view. According to this, the water flowing in the wide portion 12 </ b> A is easily flowed along the groove wall 22 </ b> A and the groove wall 23 </ b> A effectively without the flow suddenly changing by the raised portion 30.

  In the first embodiment, the raised portions 30 are provided symmetrically about the main groove center line DC in the tread surface view. For this reason, the water flowing in the wide portion 12 </ b> A is likely to flow evenly along the groove wall 22 </ b> A and the groove wall 23 </ b> A by the raised portion 30.

  In the first embodiment, the height H of the raised portion 30 is less than the depth D of the main groove 12. According to this, compared with the case where the height H of the protruding part 30 is more than the depth D of the main groove 12, the flow of water along the tire circumferential direction can be sufficiently ensured in the wide part 12A.

[Second Embodiment]
Hereinafter, a pneumatic tire 1A according to a second embodiment of the present invention will be described with reference to the drawings. In the pneumatic tire 1A according to the second embodiment, many main grooves 10 and land portions 20 of the pneumatic tire 1 according to the first embodiment are provided. Specifically, (2.1) Configuration of the pneumatic tire, (2.2) Configuration of the lug groove, and (2.3) Operation and effect will be described. In addition, the same code | symbol is attached | subjected to the same part as the pneumatic tire 1 which concerns on 1st Embodiment mentioned above, and a different part is mainly demonstrated.

(2.1) Configuration of Pneumatic Tire First, the configuration of a pneumatic tire 1A according to the second embodiment will be described with reference to the drawings. FIG. 5 is a development view showing a tread pattern of the pneumatic tire 1A according to the second embodiment. In the pneumatic tire 1A, the tread contact width TW in the tread width direction is 303 mm or more.

  As shown in FIG. 5, the main groove 10 includes a main groove 11, a main groove 12, a main groove 13, a main groove 14, and a main groove 15 from the inner side IN when the vehicle is mounted to the outer side OUT when the vehicle is mounted. Composed. The main groove 14 and the main groove 15 extend linearly along the tire circumferential direction. Other configurations of the main groove 10 are the same as those described in the first embodiment.

  The land portion 20 includes a land portion 21, a land portion 22, a land portion 23, a land portion 24, a land portion 25, and a land portion 26 from the inner side IN when the vehicle is mounted to the outer side OUT when the vehicle is mounted. The land portion 25 is formed by the main groove 14 and the main groove 15. The land portion 26 is formed outside the main groove 15 when the vehicle is mounted. In addition, about the structure of the other land part 20, it is the same as that of the content demonstrated in 1st Embodiment.

(2.2) Configuration of Lug Groove Next, the configuration of the lug groove 40 according to the present embodiment will be described with reference to FIG. As shown in FIG. 5, the lug groove 40 is constituted by a divided lug groove 40A and a terminal lug groove 40B. The divided lug groove 40A and the terminal lug groove 40B are inclined with respect to the tire circumferential direction. The divided lug groove 40A and the terminal lug groove 40B extend in a curved state from the front to the rear in the tire rotation direction.

  In addition to the divided lug groove 40A1, the divided lug groove 40A2, and the divided lug groove 40A3, the divided lug groove 40A includes a divided lug groove 40A5 formed in the land portion 25 and a divided lug groove 40A6 formed in the land portion 26. It is comprised by. The land portion 24 is not formed with the divided lug groove 40A.

  The terminal lug groove 40B includes the terminal lug groove 40B2, the terminal lug groove 40B3, and the terminal lug groove 40B4, the terminal lug groove 40B1 formed in the land portion 21, and the terminal lug groove 40B5 formed in the land portion 25. It is comprised by. The land portion 26 is not formed with the terminal lug groove 40B.

  The dividing lug groove 40A5 and the dividing lug groove 40A6 are provided along the extension line S2 along the extending direction of the dividing lug groove 40A3. That is, the terminal lug groove 40B4 intersects the extension line S2 and extends in a state curved in the direction opposite to the extension line S2.

(2.3) Action / Effect In the second embodiment, as in the first embodiment, the drainage performance of water that has entered between the road surface and the tread can be more reliably improved. Generation can be suppressed. In particular, since the pneumatic tire 1A has a wider tread contact width TW than the pneumatic tire 1 according to the first embodiment, the above-described effects are remarkable.

(3) Comparative Evaluation Next, in order to further clarify the effects of the present invention, comparative evaluation performed using pneumatic tires according to the following comparative examples and examples will be described. Specifically, (3-1) Configuration of each pneumatic tire and (3-2) evaluation results will be described with reference to Table 1. In addition, this invention is not limited at all by these examples.

(3-1) Configuration of Each Pneumatic Tire In the pneumatic tire according to Comparative Example 1, a linear groove (for example, a thick groove) that contributes most to drainage performance among the plurality of main grooves is on the tire equator line CL. Provided. In the pneumatic tire according to Comparative Example 2, a linear groove (for example, a thick groove) that contributes most to drainage performance among the plurality of main grooves is provided on the inner side IN when the vehicle is mounted with respect to the tire equator line CL.

  In the pneumatic tire according to the embodiment, the main groove 12 that contributes most to the drainage performance among the main grooves 10 is provided on the inner side IN when the vehicle is mounted with respect to the tire equator line CL. The pneumatic tire 1 described in the first embodiment is used as a front wheel, and the pneumatic tire 1A described in the second embodiment is used as a rear wheel.

(3-2) Evaluation results A vehicle equipped with each pneumatic tire is driven at a speed of 80 km / h, and only the right wheel attached to the vehicle is accelerated by entering a rainy road with a depth of 10 mm. The speed at which the speed difference (slip) between the left and right wheels was generated was defined as “hydroplaning generation speed”, and the average speed excluding the maximum and minimum values measured five times was measured.

  As a result, as shown in Table 1, because the vehicle equipped with the pneumatic tire according to the example has a higher hydroplaning generation speed than the vehicle equipped with the pneumatic tire according to Comparative Examples 1 and 2, It was found that the occurrence of hydroplaning can be suppressed.

(5) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. Specifically, in the first embodiment, the tread contact width TW of the pneumatic tire 1 is 215 mm or more. In the second embodiment, the tread contact width TW in the tread width direction is 303 mm or more in the pneumatic tire 1A. Although described as being, it is not limited to this, and the tread ground contact width TW in the tread width direction may be smaller than 215 mm or 303 mm.

  In the embodiment, the plurality of land portions 20 are formed by the plurality of main grooves 10, but the present invention is not limited to this, and at least one main groove 10 forms two land portions 20. May be.

  In the embodiment, the groove wall 22A and the groove wall 23A have been described as being provided symmetrically with respect to the main groove center line DC. However, the present invention is not limited to this, and as shown in FIG. It may be provided asymmetrically with respect to the line DC.

  In the embodiment, it has been described that only the groove width W of the main groove 12 that contributes most to the drainage performance among the plurality of main grooves 10 changes at a predetermined repetition period along the tire circumferential direction. However, the other main grooves 10 may also change at a predetermined repetition period along the tire circumferential direction.

  In the embodiment, the main groove 12 that contributes most to drainage performance among the plurality of main grooves 10 has been described as being provided on the inner side IN when the vehicle is mounted with respect to the tire equator line CL, but is not limited thereto. Alternatively, it may be provided on the outer side OUT when the vehicle is mounted with respect to the tire equator line CL. In this case, it is effective when mounted on a vehicle in which a positive camber is set.

  In the embodiment, the bottom portion 12F of the main groove 12 has been described as being provided with the raised portion 30; however, the embodiment is not limited thereto, and the raised portion 30 may not be provided. Moreover, about the shape of the protruding part 30, it can change suitably according to the objective.

  In the embodiment, the lug groove 40 has been described as being constituted by the divided lug groove 40A and the terminal lug groove 40B. However, the lug groove 40 is not limited to this, and either the divided lug groove 40A or the terminal lug groove 40B is used. It may be only.

  In the embodiment, the divided lug groove 40A and the terminal lug groove 40B have been described as being inclined with respect to the tire circumferential direction. However, the present invention is not limited to this, and may be provided along the tread width direction. . Further, the divided lug groove 40A and the terminal lug groove 40B do not necessarily need to extend in a curved state, and may extend in a straight line.

  In the embodiment, the divided lug groove 40A2 and the divided lug groove 40A3 are described as communicating with the wide portion 12A, but the present invention is not limited to this, and may not be communicated with the wide portion 12A.

  In the embodiment, the divided lug groove 40A2 and the divided lug groove 40A3 have been described as communicating with the main groove 12 (wide portion 12A). However, the present invention is not limited to this. For example, one end of the terminal lug groove 40B is It may communicate with the main groove 12. Further, the divided lug groove 40A2 and the divided lug groove 40A3 are not necessarily connected to the wide portion 12A, but may be close to the wide portion 12A, or may be connected to or close to the narrow portion 12B.

  In the embodiment, the divided lug groove 40A2 and the divided lug groove 40A3 have been described as being asymmetrical with respect to the main groove center line DC in order to reduce noise. However, the present invention is not limited to this. The main groove center line DC may be provided symmetrically. Thus, about the shape of the lug groove 40, it can change suitably according to the objective.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1,1A ... Pneumatic tire, 10 (11-15) ... Main groove, 12A ... Wide part, 12B ... Narrow part, 12F ... Bottom part, 20 (21-26) ... Land part, 22A, 23A ... Groove wall, 30 ... Raised part, 30a ... Front end, 30b ... Rear end, 30c, 30d ... Side part, 40 ... Lug groove, 40A (40A1 to 40A6) ... Dividing lug groove, 40B (40B1 to 40B5) ... Terminal lug groove

Claims (7)

Comprising a plurality of land portions formed by main grooves extending along the tire circumferential direction;
The main groove is a pneumatic tire provided on the inner side or the outer side when the vehicle is mounted with respect to the tire equator line,
The land portion is
A first land portion having a first groove wall that forms one wall surface of the main groove;
A second land portion having a second groove wall that forms the other wall surface of the main groove,
The first groove wall and the second groove wall meander along the tire circumferential direction in a tread surface view,
At least one of the first land portion or the second land portion is formed with a lug groove extending in the tread width direction,
The groove width of the main groove along the tread width direction changes at a predetermined repetition period along the tire circumferential direction ,
The main groove is provided with a wide groove portion including the maximum width portion W _MAX ,
At the bottom of the main groove is formed a raised portion that protrudes outward in the tire radial direction,
The raised portion is formed in the wide groove portion,
A first side portion of the raised portion facing the first groove wall extends along the first groove wall;
A pneumatic tire in which a second side portion of the raised portion facing the second groove wall extends along the second groove wall . The pneumatic tire according to claim 1, wherein a ratio W _MIN / W _MAX between a minimum width portion W _MIN of the groove width and a maximum width portion W _MAX of the groove width is in a range of 35% to 85%. The main groove is provided with a wide groove portion including a maximum width portion W _MAX of the groove width,
The pneumatic tire according to claim 1, wherein the lug groove is inclined with respect to the tire circumferential direction and communicates with or is close to the wide groove portion.   The pneumatic tire according to any one of claims 1 to 3, wherein a distance from the tire equator line to the main groove is 9 to 25% with respect to a tread ground contact width in the tread width direction. The first groove wall and the second groove wall have a predetermined amplitude along the tread width direction,
The pneumatic tire according to any one of claims 1 to 4, wherein the predetermined repetition period is 15 to 100 times the predetermined amplitude. The pneumatic tire according to any one of claims 1 to 5 , wherein the raised portion becomes narrower toward a front end portion and a rear end portion of the raised portion in the tread surface view. The pneumatic tire according to any one of claims 1 to 6 , wherein a height of the raised portion is less than a depth of the main groove.

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