JP5778515B2 - tire - Google Patents

Description

  The present invention relates to a tire in which a plurality of high angle grooves along the tire circumferential direction are formed in a central region in the tread width direction.

  Conventionally, for pneumatic tires (hereinafter referred to as tires) mounted on passenger cars, various tread patterns have been proposed in order to improve hydroplaning resistance on wet road surfaces while maintaining steering stability on dry road surfaces. ing.

  For example, the central region in the tread width direction has a large angle with the tread width direction (high angle), and a high angle groove (steeply inclined groove) along the tire circumferential direction is formed. There is known a tread pattern in which an angle formed with the tread width direction is smaller than that of the angle groove (low angle) and a low angle groove (slowly inclined groove) is formed along the tread width direction (for example, Patent Document 1).

  According to the tire having such a tread pattern, drainage is promoted by the high-angle groove formed in the central region in the tread width direction, so that hydroplaning resistance on a wet road surface is improved. In addition, since the land block partitioned by the low angle groove along the tread width direction is provided outside the high angle groove in the tread width direction, the rigidity of the land block against lateral force is increased. Steering stability is also maintained.

JP-A-5-286212 (FIG. 1 etc.)

  By the way, in recent years, with the progress of global warming and the like, the demand for energy saving for automobiles is increasing more than before. Under such circumstances, there is a demand for further reducing rolling resistance for tires.

  One way to reduce the rolling resistance of the tire is to reduce the thickness of the tread rubber (tread gauge). However, if the tread gauge is made thin, the depth of the groove formed in the tread cannot be increased as in the conventional case, which causes another problem.

  Specifically, there is a problem that the travel distance to the use limit due to wear of the tread is shortened and the tire life is reduced. Furthermore, if the depth of the groove is shallow, sufficient drainage from the contact surface of the tread becomes difficult, and the hydroplaning resistance decreases.

  Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a tire having the same tire life and hydroplaning resistance as a conventional tire even when the thickness of the tread rubber is reduced. To do.

A feature of the present invention is that a plurality of high angle grooves (high angle grooves 100) along the tire circumferential direction (tire circumferential direction D _C ) are formed in the central region (central region Ac) in the tread width direction (tread width direction D _T ). The tire (pneumatic tire 10) has an angle (angle θ1) formed by the high-angle groove with respect to the tire circumferential direction in a tread surface view of 15 degrees or less, and the depth of the high-angle groove is D1. Assuming that the width in the tread width direction of the land portion adjacent to the high angle groove is W, the gist is that the relationship of W / D1 ≦ 2.0 is satisfied.

  In the above-described feature of the present invention, the high-angle groove is inclined toward the other end side in the tread width direction and the linear first straight groove portion (straight groove portion 110) inclined toward the one end side in the tread width direction. And a straight second straight groove portion (straight groove portion 160).

  In the above-described feature of the present invention, an end portion (end portion 111) on the tire equator line (tire equator line CT) side of the first straight groove portion is an end portion (end portion) on the tire equator line side of the second straight groove portion. 161).

  In the above-described feature of the present invention, the depth of the high-angle groove may be 6 mm or less.

  In the above-described feature of the present invention, at least one of the first straight groove portion and the second straight groove portion on the tread shoulder side end (end portion 112, end portion 162) is more tire than the first straight groove portion. A low-angle groove (low-angle groove 200) having a large angle (angle θ2) formed with the circumferential direction communicates, and a circumferential groove (circumferential direction) extending along the tire circumferential direction is formed in a portion where the low-angle groove is formed. A groove 300) is formed, and the depth of the low-angle groove (groove depth D2) may be deeper than the depth of the circumferential groove (groove depth D3).

  In the above-described feature of the present invention, the circumferential groove includes an inclined groove portion (inclined groove portion 310) in which the groove depth of the circumferential groove increases from the tire equator line side toward the tread shoulder, and the inclined groove portion. And a groove bottom portion (groove bottom portion 360) having a deep groove depth.

  In the features of the present invention described above, the groove width (groove width GW1) at the end of the first straight groove on the tire equator line side is the groove width (groove width) at the end of the second straight groove on the tire equator line side. It may be narrower than GW2).

  According to the feature of the present invention, even when the thickness of the tread rubber is reduced, it is possible to provide a tire having the same tire life and hydroplaning resistance as that of a conventional tire.

1 is a schematic perspective view of a pneumatic tire 10 according to an embodiment of the present invention. 1 is a schematic front view of a pneumatic tire 10 according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the pneumatic tire 10 taken along the line F3-F3 shown in FIG. FIG. 3 is an enlarged view of a portion F4 shown in FIG. 2. FIG. 3 is an enlarged view of the F5 portion shown in FIG. 2. FIG. 6 is a cross-sectional view of the low-angle groove 200 taken along line F6-F6 shown in FIG.

  Next, an embodiment of a tire according to the present invention will be described with reference to the drawings. 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, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) Overall Schematic Configuration of Tire FIG. 1 is a schematic perspective view of a pneumatic tire 10 according to this embodiment. FIG. 2 is a schematic front view of the pneumatic tire 10.

  As shown in FIGS. 1 and 2, a high-angle groove 100, a low-angle groove 200, and a circumferential groove 300 are formed in the pneumatic tire 10. The pneumatic tire 10 may be filled with an inert gas such as nitrogen gas instead of air.

The high angle groove 100 is formed in the central region Ac in the tread width direction _DT . The central region Ac is a region including the tire equator line CT passing through the center in the tread width direction _DT of the pneumatic tire 10, and a normal load is applied to the pneumatic tire 10 set to a normal internal pressure defined by JATMA or the like. It shall mean a region of 1/3 of the tread width in the applied state.

High-angle groove 100 is formed in plurality along the tire circumferential direction D _C. The high angle groove 100 is a groove whose angle formed with the tread width direction is 75 degrees or more in the tread surface view. That is, the groove is such that the angle θ1 (see FIG. 4) formed with the tire circumferential direction DC (specifically, the tire equator line CT) is 15 degrees or less.

The low angle groove 200 communicates with the high angle groove 100. The low angle groove 200 has a larger angle θ2 formed with the tire circumferential direction D _C (specifically, the tire equator line CT) than the high angle groove 100. That is, the low angle groove 200 is a groove whose angle formed with the tread width direction D _T is smaller than that of the high angle groove 100.

Circumferential groove 300 is a straight groove extending along the tire circumferential direction D _C. The circumferential groove 300 is formed so as to overlap a portion where the low-angle groove 200 is formed. That is, the low angle groove 200 is formed to extend to the circumferential groove 300.

Further, in the tread width direction outer side of the circumferential groove 300, linear land portions 400 extending along the tire circumferential direction D _C is formed. Width in the tread width direction D _T of the land portion 400 is narrower than the width in the tread width direction D _T of the circumferential groove 300, and more tread width direction D _T outer land portion 400, most tread width direction D _T outside A shoulder land portion 500 is formed.

(2) Shape of Groove Next, shapes of the high angle groove 100, the low angle groove 200, and the circumferential groove 300 will be described with reference to FIGS. FIG. 3 is a cross-sectional view of the pneumatic tire 10 taken along the line F3-F3 shown in FIG. FIG. 4 is an enlarged view of the F4 portion shown in FIG. FIG. 5 is an enlarged view of the F5 portion shown in FIG. FIG. 6 is a cross-sectional view of the low-angle groove 200 taken along the line F6-F6 shown in FIG.

(2.1) High angle groove 100
The groove depth D1 (see FIG. 3) of the high angle groove 100 is 6 mm or less. Moreover, the thickness T (tread gauge) of the tread rubber of the pneumatic tire 10 is 10 mm, which is thinner than a general pneumatic tire. The thickness T is the distance from the tread contact surface to the outermost layer of the crossing belt layer 30 in the tire radial direction. As described above, the pneumatic tire 10 having a thin tread cage has a characteristic that the rolling resistance is lower than that of a general pneumatic tire.

A plurality of high angle grooves 100 are formed in the central region Ac in the tread width direction _DT . High-angle groove 100 has a large angle formed between the tread width direction D _T (High Angle) are grooves along the tire circumferential direction D _C. Specifically, the high-angle groove 100, in the tread surface view angle θ1 formed between the tire circumferential direction D _C is less than 15 degrees. However, the high angle groove 100 preferably has a certain angle (for example, 5 degrees or more) with respect to the tire circumferential direction D _C (tire equator line CT).

Further, the groove depth D1 of the high angle groove 100 and the width W in the tread width direction _DT of the land portion 60 adjacent to the high angle groove 100 satisfy the relationship of W / D1 ≦ 2.0. That is, as described above, since the thickness T of the tread rubber of the pneumatic tire 10 is 10 mm or less, the value of the groove depth D1 is smaller than that of a general pneumatic tire. Therefore, the width W of the land portion 60 cannot take a very large value, and the land portion 60 has an elongated shape.

  In the present embodiment, the high-angle groove 100 has a V shape constituted by two linear grooves. Specifically, the high-angle groove 100 includes a straight groove portion 110 and a straight groove portion 160.

The straight groove portion 110 (first straight groove portion) is a linear groove that is inclined toward one end side in the tread width direction D _T (for example, the outside when the vehicle is mounted). The straight groove portion 160 (second straight groove portion) is a linear groove that is inclined toward the other end side in the tread width direction D _T (for example, the inner side when the vehicle is mounted).

  An end 111 on the tire equator line CT side of the straight groove portion 110 communicates with an end portion 161 on the tire equator line CT side of the straight groove portion 160.

The groove width GW1 at the end 111 of the straight groove 110 is narrower than the groove width GW2 at the end 112 of the straight groove 160. Specifically, the groove width GW1 is 2.0 mm or more, and the groove width GW2 is 0.4 to the same width as the groove width GW1. As shown in FIGS. 1, 2 and 4, the groove width at the end of the straight groove portion 160 on the tire equator line CT side is narrower than the groove width at the end portion of the straight groove portion 110 on the tire equator line CT side. A high-angle groove 100 is also formed. In this embodiment, the high-angle groove 100 with a narrow groove width at the end of the straight groove 110 on the tire equator line CT side, and the high-angle groove 100 with a narrow groove width at the end of the straight groove 160 on the tire equator line CT side, There are repeated alternately along the tire circumferential direction D _C.

(2.2) Low angle groove 200
The low angle groove 200 communicates with the high angle groove 100. Specifically, the low angle groove 200 communicates with the end portion 112 (end portion 162, see FIG. 2) on the tread shoulder side of the straight groove portion 110 (and the straight groove portion 160).

The low angle groove 200 is a groove that has a small angle with the tread width direction _DT (low angle) and is along the tread width direction _DT . Specifically, low-angle groove 200, the tread surface view is a groove, such as the angle θ2 formed between the tire circumferential direction D _C is 45 degrees or more. That is, the angle θ2 of the low-angle groove 200 makes with the tire circumferential direction D _C is larger than the angle θ1 that straight groove portion 110 makes with the tire circumferential direction D _C, relative tread width direction D _T, so as to more gradually inclined This is a groove (that is, a low angle).

(2.3) Circumferential groove 300
The circumferential groove 300 is formed outside the low angle groove 200 in the tread width direction _DT . The circumferential groove 300 is formed outside the central region Ac in the tread width direction _DT . The circumferential groove 300 includes an inclined groove part 310, a notch groove part 320, and a groove bottom part 360.

The inclined groove 310 is inclined so that the groove depth D3 becomes deeper from the tire equator line CT side toward the tread shoulder. In the present embodiment, the inclined groove 310 has a gently curved shape instead of a linear shape in a cross-sectional view along the tread width direction _DT .

The notch groove portion 320 is a notch-shaped groove formed in the inclined groove portion 310. The outer end of the notch groove 320 in the tread width direction _DT communicates with the groove bottom 360. Further, the inner end of the notch groove 320 in the tread width direction _DT terminates in the inclined groove 310. Cutout groove 320 is formed between the low-angle groove 200 adjacent in the tire circumferential direction D _C.

The groove bottom portion 360 is formed at the outer end in the tread width direction _DT in the circumferential groove 300. The groove bottom 360 is deeper than the low-angle groove 200 and the inclined groove 310. Specifically, the groove depth D2 of the low-angle groove is deeper than the circumferential groove 300, specifically, the groove depth D3 of the inclined groove portion 310. That is, the low-angle groove 200 is further formed in the inclined groove portion 310 of the circumferential groove 300. Further, the groove depth of the groove bottom portion 360 of the circumferential groove 300 is deeper than that of the low-angle groove 200, and the groove depth increases in the order of the inclined groove portion 310, the low-angle groove 200, and the groove bottom portion 360.

(3) Action / Effect According to the pneumatic tire 10, the groove depth D1 of the high angle groove 100 is 6 mm or less. That is, since the thickness T of the tread rubber of the pneumatic tire 10 is thinner than a general pneumatic tire, the rolling resistance is reduced. Further, since the angle θ1 to the high-angle groove 100 makes with the tire circumferential direction D _C is less than 15 degrees, is good drainage of rain water that has entered the high-angle grooves 100. That is, resistance to hydroplaning can be ensured.

Further, the groove depth D1 of the high angle groove 100 and the width W in the tread width direction _DT of the land portion 60 adjacent to the high angle groove 100 satisfy the relationship of W / D1 ≦ 2.0. That is, since the width of the land portion 60 is narrower in the tread width direction D _T, the land portion 60 is suppressed to be deformed so as turned up in the tire circumferential direction D _C at the time of braking, the braking performance is improved. Further, since the width of the land portion 60 is narrow, forced wear (wear caused by an external force (such as braking force) acting on the pneumatic tire 10) in the central region Ac is reduced.

  That is, according to the pneumatic tire 10, even when the thickness T of the tread rubber is reduced, the tire life and hydroplaning resistance equivalent to those of the conventional tire are obtained.

  Further, in the present embodiment, the high angle groove 100 forms a V shape by the straight groove portion 110 and the straight groove portion 160. Specifically, the end 111 of the straight groove 110 communicates with the end 161 of the straight groove 160. For this reason, it is possible to efficiently drain rainwater that has entered the central region Ac. In addition, since the groove width GW1 of the straight groove portion 110 is narrower than the groove width GW2 of the straight groove portion 160, it is possible to suppress a significant decrease in the rigidity of the land portion 60 around the communication portion between the straight groove portion 110 and the straight groove portion 160.

  Further, the low angle groove 200 communicates with the high angle groove 100, and a circumferential groove 300 is formed at a portion where the low angle groove 200 is formed. Further, the groove depth D2 of the low-angle groove 200 is deeper than the groove depth D3 of the circumferential groove 300. For this reason, although the groove width of the high-angle groove 100 is narrow, it becomes possible to actively guide rainwater that has entered the central region Ac to the low-angle groove 200 and the circumferential groove 300, and drainage can be further improved.

Further, the circumferential grooves 300, the inclined groove portion 310, deep groove depth than the inclined groove 310, because it has a groove bottom portion 360 extending in the tire circumferential direction D _C, drainage of rainwater that has entered the center area Ac Further advantageous.

  Since the low-angle groove 200 is used, the angle formed between the low-angle groove 200 and the circumferential groove 300 in the tread surface view is increased, and the land block at the portion where the low-angle groove 200 and the circumferential groove 300 communicate with each other Tapering is avoided, and a reduction in rigidity and a loss of the land block can be suppressed.

  A tread pattern such as the pneumatic tire 10 can be formed because the groove depths of the high angle groove 100, the low angle groove 200, and the circumferential groove 300 are a special setting of 6 mm or less. In the case of a normal groove depth (for example, 10 mm), since the rigidity of the land portion 60 becomes too weak, it is difficult to use such a tread pattern in practice. Such a tread pattern can be suitably used as a tread for a retread that replaces only the worn tread portion.

(4) 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 descriptions 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. In the embodiment described above, the low-angle groove 200 and the circumferential groove 300 are formed. However, the low-angle groove 200 and the circumferential groove 300 do not necessarily have to be formed.

In the embodiment described above, the straight groove portion 110 and the straight groove portion 160 constituting the high angle groove 100 are both linear, but the high angle groove 100 is not linear, for example, outside the tread width direction D _T. A shape that gently curves toward the surface may be used.

  Further, the high-angle groove 100 may not be V-shaped so that the linear groove portion 110 and the linear groove portion 160 communicate with each other.

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

10 ... Pneumatic tire
30 ... Intersection belt layer
60 ... Land
100 ... High angle groove
110 ... Linear groove
111, 112 ... end
160 ... Linear groove
161, 162 ... end
200 ... Low angle groove
300 ... Circumferential groove
310 ... Inclined groove
320 ... Notch groove
360 ... groove bottom
400 ... Land
500 ... Shoulder land

Claims (8)

A tire in which a plurality of high-angle grooves along the tire circumferential direction are formed in the central region in the tread width direction,
In the tread surface view, the angle formed by the high angle groove with the tire circumferential direction is 15 degrees or less,
When the depth of the high angle groove is D1, and the width in the tread width direction of the land portion adjacent to the high angle groove is W, the relationship of W / D1 ≦ 2.0 is satisfied ,
The high angle groove is
A linear first linear groove portion inclined toward one end side in the tread width direction;
A linear second linear groove portion inclined toward the other end side in the tread width direction;
Including
The end portion on the tread shoulder side of at least one of the first straight groove portion or the second straight groove portion communicates with a low angle groove having a larger angle with the tire circumferential direction than the first straight groove portion,
In the portion where the low-angle groove is formed, a circumferential groove extending along the tire circumferential direction is formed,
The circumferential groove is
An inclined groove portion in which the groove depth of the circumferential groove increases from the tire equator line side toward the tread shoulder;
A notch groove that is a notch-shaped groove formed in the inclined groove, and
A groove bottom portion having a deeper groove depth than the inclined groove portion;
Including tires. The tire according to claim 1, wherein an outer end in the tread width direction of the notch groove portion communicates with the groove bottom portion, and an inner end in the tread width direction of the notch groove portion terminates in the inclined groove portion. The tire according to claim 2, wherein the notch groove portion is formed between adjacent low angle grooves in the tire circumferential direction. The tire according to any one of claims 1 to 3 , wherein an end of the first straight groove portion on the tire equator line side communicates with an end portion of the second straight groove portion on the tire equator line side. The tire according to any one of claims 1 to 4 , wherein a groove depth of the high-angle groove is 6 mm or less. The tire according to any one of claims 1 to 5 , wherein a depth of the low-angle groove is deeper than a depth of the circumferential groove. Said first straight groove width at the ends of the tire equator line side of the groove, according to any one of the narrow claims 1 to 6 than the groove width at the end of the second straight groove tire equator line side tire. A high-angle groove having a narrow groove width at an end portion on the tire equator line side of the first straight groove portion and a high-angle groove having a narrow groove width at an end portion on the tire equator line side of the second straight groove portion are in a tire circumferential direction. The tire according to any one of claims 1 to 7, wherein the tire is repeated alternately along.

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