JP5216382B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire including at least a circumferential groove extending in the tire circumferential direction and an inclined lug groove extending from the circumferential groove toward an end portion in the red width direction.

  2. Description of the Related Art Conventionally, in a pneumatic tire mounted on a vehicle, a tread pattern in which a circumferential groove extending in the tire circumferential direction and an inclined lug groove extending from the circumferential groove toward the outer side in the red width direction is known. (For example, refer to Patent Document 1 and Patent Document 2).

In this tread pattern, the inclined lug groove is inclined toward the outer side in the tread width direction while being directed from the circumferential groove toward the tire circumferential direction (suddenly curved), whereby drainage in the tire circumferential direction is caused by the circumferential groove. It is possible to drain water from the tire circumferential direction to the tread width direction by the inclined lug groove.
JP-A-8-85309 (FIGS. 1 and 3) JP 2002-114209 A (FIGS. 1 and 3)

  However, the conventional pneumatic tire described above has the following problems. That is, in the conventional pneumatic tire, although drainage performance can be ensured, when the block defined by the circumferential groove and the inclined lug groove contacts the ground, a weak rigid portion and a strong rigid portion are generated. As a result, steering stability and wear resistance may be deteriorated.

  Specifically, on the side where the circumferential groove and the inclined lug groove are connected, the block length, which is the length of the block in the tire circumferential direction, is short and has a sharp shape, so that the rigidity is weakened. On the other hand, on the end side in the tread width direction of the inclined lug groove, the block length is long and the rigidity becomes strong. In other words, non-uniform rigidity occurs within one block, which may deteriorate steering stability and wear resistance.

  Then, this invention is made | formed in view of such a condition, and it aims at providing the pneumatic tire which can also improve steering stability and abrasion resistance, improving drainage performance. To do.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is formed in a circumferential groove extending in the tire circumferential direction and an outer land portion located on the outer side when the vehicle is mounted with respect to the tire equator line, and from the circumferential groove to the outer side in the tread width direction. An inclined lug groove extending incline toward the tire, and an inclined slope groove formed on an inner land portion located on the inner side when the vehicle is mounted with respect to the tire equator line and extending inclined from the circumferential groove toward the outer side in the tread width direction The inclined slope groove has one end connected to the circumferential groove and the other end terminated in the inner land, and the depth of the inclined slope groove gradually increases from the circumferential groove side toward the outer side in the tread width direction. The main point is to become deeper.

  According to such a feature, the slope of the inclined slope groove gradually becomes deeper from the circumferential groove side toward the outer side in the tread width direction, so that rigidity is increased in the vicinity of the tire equator line where the contact pressure is high, that is, The inner land portion (block) in the vicinity of the circumferential groove can achieve uniform rigidity, and can improve steering stability and wear resistance.

  Further, since the slope slope groove is provided in addition to the slope lug groove, the groove area can be made wider than the ground contact area when the tread portion is grounded, and the drainage performance can be improved.

  Another feature is that the slope groove circumferential length, which is the length of the inclined slope groove with respect to the tire circumferential direction, gradually decreases from the tire equator line side toward the outer side in the tread width direction.

  According to such a feature, the circumferential length of the slope groove is gradually shortened from the tire equator line side toward the outer side in the tread width direction, so that the groove area is further increased with respect to the ground contact area when the tread portion is grounded. Thus, drainage performance can be further improved.

  In addition, the slope groove circumferential length is increased at the shallow slope groove position, and the slope groove circumferential length is shortened at the deep slope groove depth position. The rigidity of the formed block can be made uniform, and the steering stability and wear resistance can be further improved.

  Another feature is that the connecting portion depth, which is the depth from the tire surface of the connecting portion between the circumferential groove and the inclined slope groove, is 0 to 50% with respect to the depth of the deepest circumferential groove. The gist.

  According to this feature, the rigidity of the block defined by the circumferential groove and the inclined slope groove can be set by having the connecting portion depth of 0 to 50% with respect to the deepest circumferential groove depth. As a result, it is possible to improve steering stability and wear resistance, and to set the depth of the inclined slope groove, thereby improving drainage performance.

  Another feature is summarized in that the inclined slope groove is continuous with the inclined lug groove in the circumferential groove.

  According to this feature, the inclined slope groove is continuous with the inclined lug groove in the circumferential groove, so that water absorbed near the tire equator line can be easily drained to the end in the tread width direction, and drainage performance is further improved. Can do.

  Another feature is that the depth of the circumferential groove gradually increases from the outside when the vehicle is mounted to the inside when the vehicle is mounted.

  According to this feature, the rigidity of the outer land portion where the inclined lug groove is formed can be ensured by gradually increasing the depth of the circumferential groove from the outside when the vehicle is mounted toward the inside when the vehicle is mounted. Further, steering stability and wear resistance can be further improved.

  The other feature is summarized in that the inclined lug groove is folded back toward the tire equator line side on the end side in the tread width direction and is terminated in the outer land portion.

  According to such a feature, the inclined lug groove is folded back toward the tire equator line side on the tread width direction end side, so that the edge portion increases in the outer land portion, so that driving performance such as drivability and braking performance is improved. Can be made.

  Another feature of the present invention is that it is further provided with a branch groove that is formed in the inner land portion and branches and extends from the tire equator line side toward the outer side in the tread width direction.

  According to such a feature, since the edge portion is increased in the inner land portion by further providing the branch groove, it is possible to further improve the steering stability and further improve the drainage performance in the inner land portion. Can do.

  Another feature is summarized as further comprising a plurality of fine holes formed in the inner land portion and recessed from the tire surface.

  According to this feature, since the edge portion is increased in the inner land portion by further providing the narrow hole, it is possible to improve driving performance such as drivability and braking performance.

  ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire which can improve steering stability and abrasion resistance can be provided, improving drainage performance.

  Next, an example of a pneumatic 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 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.

  FIG. 1 is a partially enlarged perspective view showing a pneumatic tire according to this embodiment, FIG. 2 is a development view showing a tread pattern of the pneumatic tire according to this embodiment, and FIG. It is sectional drawing (AA sectional drawing of FIG. 2) which shows the circumferential groove | channel of the pneumatic tire which concerns on this Embodiment, FIG. 4 is a cross section which shows the inclined lug groove of the pneumatic tire which concerns on this Embodiment. It is a figure (BB sectional drawing of FIG. 2).

  5 is a cross-sectional view (CC cross-sectional view of FIG. 2) showing the inclined slope groove of the pneumatic tire according to the present embodiment. FIG. 6 is a cross-sectional view of the pneumatic tire according to the present embodiment. It is sectional drawing (DD sectional drawing of FIG. 2) which shows a branch groove, FIG.7 (a) is sectional drawing (EE) which shows the spherical hole (narrow hole) of the pneumatic tire which concerns on this Embodiment. FIG. 7B is a cross-sectional view (FF cross-sectional view) showing a triangular hole (narrow hole) of the pneumatic tire according to the present embodiment.

  The pneumatic tire 1 according to the present embodiment is a general radial tire including a bead portion, a carcass layer, and a belt layer (not shown).

  As shown in FIGS. 1 and 2, the pneumatic tire 1 includes a circumferential groove 3 extending in the tire circumferential direction, an inclined lug groove 5 extending from the circumferential groove 3 toward the outer side in the tread width direction, An inclined slope groove 7 extending from the directional groove 3 toward the outer side in the tread width direction is provided.

  The circumferential groove 3 is formed on the tire equator line CL. Specifically, as shown in FIG. 3, the depth (D1) of the circumferential groove 3 gradually increases from the outer side when the vehicle is mounted to the inner side when the vehicle is mounted. The circumferential groove 3 defines an outer land portion 9A located outside when the vehicle is mounted with reference to the tire equator line CL, and an inner land portion 9B positioned inside when the vehicle is mounted with reference to the tire equator line CL. ing.

  The inclined lug groove 5 is formed in the outer land portion 9A. Specifically, the inclined lug groove 5 is folded back toward the tire equator line CL side at the end side in the tread width direction, and is terminated in the outer land portion 9A. Further, the depth (D2) of the inclined lug groove 5 is substantially the same as the depth (D1) of the deepest circumferential groove 3 as shown in FIG.

On the end side of the inclined lug groove 5 located near the tire equator line CL , the lug groove circumferential length (L1) that is the length of the inclined lug groove 5 with respect to the tire circumferential direction is the tread width direction from the vicinity of the tire equator line CL. It gradually narrows toward the outside (see FIG. 2).

  The inclined slope groove 7 is formed in the inner land portion 9B. Specifically, the slope slope groove 7 has one end connected to the circumferential groove 3 and the other end terminated in the inner land portion 9B. The inclined slope groove 7 is continuous with the inclined lug groove 5 in the circumferential groove 3.

As shown in FIG. 5, the depth (D3) of the inclined slope groove 7 gradually becomes deeper from the circumferential groove 3 side toward the outer side in the tread width direction.

  The slope groove width (W1) that is the maximum width in the tread width direction of the inclined slope groove 7 is 5 to 60% with respect to the inner land portion width (W2) that is the width in the tread width direction of the inner land portion 9B. Preferably there is.

  If the slope groove width (W1) is smaller than 5% of the inner land width (W2), the groove area becomes narrower than the ground contact area when the tread part contacts the ground, ensuring drainage performance. There are things you can't do. On the other hand, if the slope groove width (W1) is larger than 60% with respect to the inner land portion width (W2), the rigidity of the inner land portion 9B (the block defined by the circumferential groove 3 and the inclined slope groove 7) decreases. As a result, non-uniform rigidity occurs in the block, and steering stability and wear resistance may deteriorate.

  Further, the slope groove circumferential length (L2), which is the length of the inclined slope groove 7 with respect to the tire circumferential direction, gradually decreases from the tire equator line CL side toward the outer side in the tread width direction (see FIGS. 1 and 2). . That is, the inclined slope groove 7 has a triangular shape in a top view.

  In the inner land portion 9B where the inclined slope groove 7 is provided, a branch groove 11 that branches and extends from the tire equator line CL side toward the outer side in the tread width direction and a plurality of fine holes 13 that are recessed from the tire surface are formed. Has been.

  The depth (D4) of the branch groove 11 gradually increases from the circumferential groove 3 side toward the tread width direction intermediate portion of the branch groove 11 as shown in FIG. Note that the depth (D4) of the deepest branch groove 11 is substantially the same as the depth (D1) of the deepest circumferential groove 3.

  The plurality of thin holes 13 include a spherical hole 13A that is a semicircular spherical hole and a triangular hole 13B that is a triangular hole. The depth (D5) of the spherical hole 13A is shallower than each groove (the circumferential groove 3, the inclined lug groove 5, the inclined slope groove 7, and the branch groove 11) as shown in FIG. The depth (D6) of the triangular hole 13B gradually increases from the tire equator line CL side toward the tread width direction as shown in FIG. 7B. The depth (D6) of the triangular hole 13B is shallower than each groove (the circumferential groove 3, the inclined lug groove 5, the inclined slope groove 7, and the branch groove 11).

  Here, the connecting portion depth (D3 ′), which is the depth of the connecting portion 15 between the circumferential groove 3 and the inclined slope groove 7 from the tire surface, is smaller than the deepest circumferential groove 3 depth (D1). 0 to 50% is preferable.

  In addition, when the connecting portion depth (D3) is deeper than 50% with respect to the depth (D1) of the deepest circumferential groove 3, the inner land portion 9B (the circumferential groove 3 and the inclined slope groove 7) is defined. The rigidity of the block) is lowered, and the rigidity is uneven in the block, so that steering stability and wear resistance may be deteriorated.

(Action / Effect)
According to the pneumatic tire 1 according to the present embodiment described above, the ground pressure is high because the depth of the inclined slope groove 7 gradually increases from the circumferential groove 3 side toward the outer side in the tread width direction. The rigidity is increased in the vicinity of the tire equator line, that is, the rigidity can be made uniform in the inner land portion 9B (block) in the vicinity of the circumferential groove 3, and the steering stability and the wear resistance can be improved.

  Further, since the inclined slope groove 7 is provided in addition to the inclined lug groove 5, the groove area can be increased with respect to the ground contact area when the tread portion is grounded, and the drainage performance can be improved. .

Further, the slope groove circumferential length ( L2 ) is gradually shortened from the tire equator line side toward the outer side in the tread width direction, so that the groove area can be further increased with respect to the ground contact area when the tread portion is grounded. The drainage performance can be further improved.

The depth of the inclined slope groove 7 (D3) becomes long slope groove circumferential length (L2) at a shallow position, the depth of the inclined slope groove 7 (D3) is a deep position in the slope groove circumferential length (L2) Therefore, the rigidity of the blocks defined by the circumferential grooves 3 and the inclined slope grooves 7 can be made uniform, and the steering stability and wear resistance can be further improved.

  Further, since the connecting portion depth (D3 ′) is 0 to 50% with respect to the deepest circumferential groove 3 depth (D1), the blocks defined by the circumferential groove 3 and the inclined slope groove 7 As the rigidity can be set, the steering stability and the wear resistance can be improved, and the depth of the inclined slope groove 7 can be set, so that the drainage performance can be improved.

  In addition, the slope slope groove 7 is continuous with the slope lug groove 5 in the circumferential groove 3 so that water absorbed near the tire equator line CL can be easily drained to the end in the tread width direction, and drainage performance is further improved. Can do.

  Further, the depth (D1) of the circumferential groove 3 gradually increases from the outer side when the vehicle is mounted to the inner side when the vehicle is mounted, thereby ensuring the rigidity of the outer land portion 9A in which the inclined lug groove 5 is formed. The steering stability and wear resistance can be further improved.

  In addition, since the inclined lug groove 5 is folded back toward the tire equator line CL side at the end side in the tread width direction, the edge portion increases in the outer land portion 9A, so that driving performance such as drivability and braking performance is improved. be able to.

  Further, since the edge portion is increased in the inner land portion 9B by further providing the branch groove 11, the steering stability can be further improved, and the drainage performance in the inner land portion can be further improved. .

  Further, by further providing the narrow holes 13 (the spherical holes 13A and the triangular holes 13B), the edge portion increases in the inner land portion 9B, so that it is possible to improve traveling performance such as drivability and braking performance.

[Other Embodiments]
Although the contents of the present invention have been disclosed through the embodiments of the present invention as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention.

  Specifically, the pneumatic tire 1 has been described as a general radial tire including a bead portion, a carcass layer, and a belt layer (not shown). However, the pneumatic tire 1 is not limited to this and is not a radial tire. Tires (for example, bias tires).

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. 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.

  Next, in order to further clarify the effects of the present invention, test results performed using pneumatic tires according to the following examples and comparative examples will be described. In addition, this invention is not limited at all by these examples.

  Data regarding each pneumatic tire is measured under the following conditions.

・ Tire size: 245 / 45R19
・ Wheel size: 19 × 8.0J
・ Internal pressure condition: 230 kpa
-Load condition: Equivalent to two passengers-Vehicle type: General passenger car As described in the above-described embodiment, the pneumatic tire according to the example is the circumferential groove 3, the inclined lug groove 5, and the inclined slope groove 7. And a branch groove 11 and a narrow hole 13 (ball hole 13A and triangular hole 13B). Details of each groove are shown in Table 1.

  The pneumatic tire according to the comparative example is obtained by changing the configuration of the inclined slope groove of the pneumatic tire in the example. Specifically, as shown in FIG. 8, the pneumatic tire according to the comparative example includes a circumferential groove 3, an inclined lug groove 5, a branch groove 11, and a narrow hole 13 (ball hole 13 </ b> A and triangular hole 13 </ b> B). And.

これらの実施例及び比較例に係る空気入りタイヤのハイドロプレーニング性、操縦安定性及び耐摩耗性について、表２を用いて説明する。

＜ハイドロプレーニング性＞
各空気入りタイヤを装着した車両で水深５ｍｍの直線状のウエット路面を走行し、比較例に係る空気入りタイヤが浮き上がって滑走する現象であるハイドロプレーニングが発生する限界速度を‘１００’とし、実施例に係る空気入りタイヤのハイドロプレーニングが発生する限界速度を指数化した。なお、指数が大きいほど、ハイドロプレーニングが発生する限界速度が大きく、ハイドロプレーニング性に優れている。 The inclined lug groove 5 has an outer lug groove 5A located in the outer land portion 9A and an inner lug groove 5B located in the inner land portion 9B. The outer lug groove 5A has the same shape as the inclined lug groove 5 described in the embodiment. On the other hand, the inner lug groove 5 </ b> B extends from the circumferential groove 3 toward the outer side in the tread width direction, is folded back toward the tire equator line CL, and terminates at the circumferential groove 3. That is, the pneumatic tire according to the comparative example is the same as the pneumatic tire according to the embodiment except for the configuration of the inner lug groove 5B. Details of each groove are shown in Table 1.

The hydroplaning property, steering stability, and wear resistance of the pneumatic tires according to these examples and comparative examples will be described with reference to Table 2.

<Hydroplaning property>
Running on a straight wet road surface with a water depth of 5 mm with a vehicle equipped with each pneumatic tire, the critical speed at which hydroplaning, a phenomenon in which the pneumatic tire according to the comparative example floats and slides, is set to '100'. The critical speed at which hydroplaning of the pneumatic tire according to the example occurs was indexed. In addition, the larger the index, the greater the critical speed at which hydroplaning occurs and the better the hydroplaning property.

  As a result, as shown in Table 2, it was found that the pneumatic tire according to the example was superior in hydroplaning properties as compared with the pneumatic tire according to the comparative example. That is, in the pneumatic tire according to the example, the depth (D3) of the inclined slope groove 7 gradually becomes deeper from the circumferential groove 3 side toward the outer side in the tread width direction.

<Steering stability (dry and wet surfaces)>
Driving on a dry road surface with a vehicle equipped with each pneumatic tire, the driving stability of the pneumatic tire according to the comparative example is set to '100', and the driving stability of the pneumatic tire according to the example on the dry road surface is a test driver The feeling was evaluated. In addition, the larger the index, the better the steering stability on the dry road surface.

  Similarly, the vehicle equipped with each pneumatic tire travels on a wet road surface, the steering stability of the pneumatic tire according to the comparative example is set to '100', and the steering stability of the pneumatic tire according to the example on the wet road surface The feeling was evaluated with a test driver. The larger the index, the better the steering stability on the wet road surface.

  As a result, as shown in Table 2, it was found that the pneumatic tire according to the example was superior in handling stability on the dry road surface and the wet road surface as compared with the pneumatic tire according to the comparative example. That is, in the pneumatic tire according to the example, the depth (D3) of the inclined slope groove 7 gradually becomes deeper from the circumferential groove 3 side toward the outer side in the tread width direction, so that the steering stability on the dry road surface and the wet road surface is stable. It has been found that the performance is improved.

<Abrasion resistance>
The vehicle equipped with each pneumatic tire travels 5000 km on a dry road surface, the step amount of the block defined by each groove of the pneumatic tire according to the comparative example is set to '100', and each groove of the pneumatic tire according to the example The step difference of the block divided by is indexed. In addition, the larger the index, the smaller the step amount of the block and the better the wear resistance.

  As a result, as shown in Table 2, it was found that the pneumatic tire according to the example was superior in wear resistance as compared with the pneumatic tire according to the comparative example. That is, in the pneumatic tire according to the example, the depth (D3) of the inclined slope groove 7 gradually becomes deeper from the circumferential groove 3 side toward the outer side in the tread width direction, and thus it was found that the wear resistance is improved.

1 is a partially enlarged perspective view showing a pneumatic tire according to the present embodiment. It is an expanded view which shows the tread pattern of the pneumatic tire which concerns on this Embodiment. It is sectional drawing (AA sectional drawing of FIG. 2) which shows the circumferential groove | channel of the pneumatic tire which concerns on this Embodiment. It is sectional drawing (BB sectional drawing of FIG. 2) which shows the inclination lug groove of the pneumatic tire which concerns on this Embodiment. It is sectional drawing (CC sectional drawing of FIG. 2) which shows the inclination slope groove | channel of the pneumatic tire which concerns on this Embodiment. FIG. 3 is a cross-sectional view (a DD cross-sectional view in FIG. 2) showing a branch groove of the pneumatic tire according to the present embodiment. It is sectional drawing (EE sectional drawing, FF sectional drawing) which shows the narrow hole of the pneumatic tire which concerns on this Embodiment. It is an expanded view which shows the tread pattern of the pneumatic tire which concerns on a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 3 ... Circumferential groove, 5 ... Inclined lug groove, 7 ... Inclined slope groove, 9A ... Outer land part, 9B ... Inner land part, 11 ... Branch groove, 13 ... Narrow hole, 13A ... Spherical hole , 13B ... triangular hole, 15 ... connecting part

Claims (8)

A circumferential groove extending in the tire circumferential direction;
An inclined lug groove formed on an outer land portion located on the outer side when the vehicle is mounted with respect to the tire equator line, and extending inclined from the circumferential groove toward the outer side in the tread width direction;
An inclined slope groove formed on an inner land portion positioned on the inner side when the vehicle is mounted with respect to the tire equator line, and extending inclined from the circumferential groove toward the outer side in the tread width direction,
The inclined slope groove has one end connected to the circumferential groove and the other end terminated in the inner land portion,
The depth of the inclined slope groove gradually increases from the circumferential groove side toward the outer side in the tread width direction.   The pneumatic groove according to claim 1, wherein a slope groove circumferential length, which is a length of the inclined slope groove with respect to a tire circumferential direction, gradually decreases from the tire equator line side toward a tread width direction outer side. tire.   The connecting portion depth, which is the depth from the tire surface of the connecting portion between the circumferential groove and the inclined slope groove, is 0 to 50% with respect to the deepest circumferential groove depth. The pneumatic tire according to claim 1.   The pneumatic tire according to claim 1, wherein the inclined slope groove is continuous with the inclined lug groove in the circumferential groove.   2. The pneumatic tire according to claim 1, wherein the depth of the circumferential groove gradually increases from an outer side when the vehicle is mounted to an inner side when the vehicle is mounted.   2. The pneumatic tire according to claim 1, wherein the inclined lug groove is folded back toward the tire equator line side at a tread width direction end portion side and is terminated within the outer land portion.   2. The pneumatic tire according to claim 1, further comprising a branch groove formed in the inner land portion and branching and extending from the tire equator side toward the outer side in the tread width direction.   The pneumatic tire according to claim 1, further comprising a plurality of fine holes formed in the inner land portion and recessed from the tire surface.

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