JP2005112030A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire, implementing compatibility of wet performance and noise performance. <P>SOLUTION: This pneumatic tire has a tread surface 10 of a directional tread pattern including two or more circumferential grooves 11 connected in the circumferential direction of the tire and a lateral groove 12, at least one end of which is connected to the circumferential grooves 11. A shielding plate 20 partially shielding the circumferential groove 11 is provided in the circumferential groove 11, and the shielding plate 20 is disposed on the opposite side to the tire rotating direction R of a communicating part 12a where the lateral groove 12 is connected to the circumferential grooves. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire having a directional tread pattern including circumferential grooves and lateral grooves, and more particularly to a pneumatic tire capable of achieving both wet performance and noise performance.

  In general, noise is generated when a pneumatic tire contacts the road surface. This noise is mainly a pattern air pumping sound generated when the air in the grooves constituting the tread surface (mainly the circumferential grooves formed in the tire circumferential direction) is subjected to compression and discharge pumping action. The groove on the tread surface of the rolling pneumatic tire changes its volume by compressing and deforming the surrounding blocks that make up the groove when the pneumatic tire contacts the ground, and the air in the groove changes. It is compressed and causes air column resonance, and a part is released to the outside of the groove. Noise is generated by air column resonance in the air in the groove.

  In order to reduce the above noise, that is, to improve the noise performance, it is important to reduce the air column resonance generated in the groove, and the number of grooves constituting the tread surface, particularly the circumferential grooves, may be reduced. It is common to reduce the volume of the circumferential groove. However, when the groove on the tread surface is formed as described above, there is a problem that wet performance, particularly drainage performance when water between the tread surface and the road surface of the pneumatic tire is drained to the outside of the tread surface is deteriorated. It was. Therefore, a pneumatic tire is proposed in which a shielding plate (thin film plate) that shields the circumferential groove is disposed in the circumferential groove. This conventional pneumatic tire shields all or part of the groove cross section in the tire width direction of the circumferential groove.

Japanese Patent Laid-Open No. 5-131813

  Here, in the conventional pneumatic tire described above, when the shielding plate covers the entire groove cross section in the tire width direction of the circumferential groove, air column resonance of the circumferential groove can be reduced and noise performance can be improved. it can. However, the water located on the front side in the tire rotation direction from the shielding plate in the circumferential groove cannot move to the rear side in the tire rotation direction from the shielding plate in the circumferential groove, so that the drainage performance is lowered and wet. There was a problem that the performance deteriorated. On the other hand, when the shielding plate partially shields the groove cross section in the tire width direction of the circumferential groove, it is possible to suppress a decrease in drainage compared to the case where the groove cross section of the circumferential groove in the tire width direction is entirely shielded. However, as compared with the drainage of a pneumatic tire in which no shielding plate is arranged in the circumferential groove, it is not possible to reliably suppress a decrease in drainage, and it is possible to reliably suppress a decrease in wet performance. could not. Further, since the support of the shielding plate in the circumferential groove is weakened, and the rigidity of the shielding plate is lowered, there is a risk that the shielding plate is prematurely worn or damaged.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can aim at coexistence with at least wet performance and noise performance.

  In order to solve the above-described problems and achieve the object, according to the present invention, a directional tread pattern including a plurality of circumferential grooves continuous in the tire circumferential direction and a lateral groove having at least one end communicating with the circumferential groove. In the pneumatic tire having the tread surface, the circumferential groove has a shielding plate that shields a part of the circumferential groove, and the shielding plate has a tire rotation direction of the communication portion in which the lateral groove communicates with the circumferential groove. It is arranged on the opposite side.

  In addition, it is preferable that at least one shielding plate is disposed in the contact surface of the pneumatic tire. Moreover, it is preferable that the shielding plate is disposed at least in the circumferential groove formed on the tire center side in the circumferential groove. Furthermore, the cross-sectional area BA in the tire width direction of the shielding plate is preferably 1/2 to 2/3 of the cross-sectional area GA in the tire width direction of the circumferential groove.

  According to this invention, since the shielding plate for shielding a part of the circumferential groove is disposed in the circumferential groove, air column resonance of the circumferential groove can be reduced. In addition, water that is not blocked by the shielding plate in the circumferential direction groove from the shielding plate in the circumferential groove is not blocked by the shielding plate. ) On the other hand, a part of the water blocked by the shielding plate moves beyond the shielding plate to the opposite side of the tire rotation direction, and the other water moves from the communicating portion to the lateral groove. Therefore, the water located on the tire rotation direction side from the shielding plate in the circumferential groove does not stay in the circumferential groove near the shielding plate, but moves from the shielding plate to the side opposite to the tire rotation direction or the lateral groove. The lateral grooves are formed so as to communicate with adjacent circumferential grooves or open to the outside of the ground contact surface of the pneumatic tire. That is, the water that has moved to the lateral groove is repeatedly moved from the circumferential groove to the lateral groove and from the lateral groove to the circumferential groove, and finally drained to the outside of the pneumatic tire. Thereby, it can suppress that drainage falls.

  In the present invention, the shielding plate is supported by both the side wall surface forming the circumferential groove and the groove bottom surface.

  According to this invention, the shielding plate is supported by the three locations of the opposing side wall surface of the circumferential groove and the groove bottom surface of the circumferential groove. Therefore, compared with the shielding plate of the conventional pneumatic tire supported by one side wall surface and a part of the groove bottom surface, the shielding plate is supported more strongly in the circumferential groove, and the rigidity of the shielding plate is reduced. Can be suppressed.

  In the present invention, the cross-sectional area BA of the shielding plate in the tire width direction increases from the tire shoulder side to the tire center side inward in the tire radial direction.

  According to this invention, the shielding plate shields more on the tire shoulder side of the circumferential groove, that is, on the communication portion side where the lateral groove communicates with the circumferential groove than on the tire center side. Therefore, the amount of water that moves to the horizontal groove out of the water blocked by the shielding plate increases, and the water in the circumferential groove can be reliably moved to the horizontal groove. Thereby, it can suppress that drainage falls further.

  In the present invention, the angle of the shielding plate with respect to the tire circumferential direction is the same as the angle of the lateral groove with respect to the tire circumferential direction.

  According to this invention, one of the lateral groove side wall surfaces constituting the lateral groove extends into the circumferential groove as a shielding plate having a constant angle with respect to the tire circumferential direction. Accordingly, more of the water blocked by the shielding plate moves to the horizontal groove, and the water can smoothly move to the horizontal groove. Thereby, it can suppress that drainage falls further.

  Further, in the present invention, the shielding plate is characterized in that the side surface opposite to the tire rotation direction is flared toward the inside in the tire radial direction.

  According to this invention, the shielding plate is supported on the groove bottom surface of the circumferential groove in a wide area. That is, the shielding plate can be reinforced against the force received on the side opposite to the tire rotation direction when the pneumatic tire rotates. Therefore, the support of the shielding plate in the circumferential groove is further strengthened, and it is possible to further suppress a decrease in the rigidity of the shielding plate.

  The pneumatic tire according to the present invention can suppress the deterioration of drainage and can reduce the air column resonance of the circumferential groove, so that both wet performance and noise performance can be achieved. There is an effect. In addition, since the support of the shielding plate in the circumferential groove is strengthened and the rigidity of the shielding plate can be suppressed from decreasing, premature wear and damage of the shielding plate due to the rotation of the pneumatic tire can be prevented. Can be suppressed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. In addition, since the internal structure of the pneumatic tire in the following embodiments is the same as that of a general radial tire or bias tire, the description thereof is omitted.

  FIG. 1 is a diagram showing a configuration example of a pneumatic tire according to the present invention. 2 is an enlarged perspective view of a portion A in FIG. 3-1 is a plan view of the shielding plate, FIG. 3-2 is a front view of the shielding plate, and FIG. 3-3 is a cross-sectional view taken along line BB in FIG. 3-1. As shown in FIG. 1, a pneumatic tire 1 according to the present invention has a directional tread pattern on a tread surface 10. In addition, the arrow R is the tire rotation direction of the pneumatic tire 1 according to the present invention, and S is the contact surface when the pneumatic tire 1 according to the present invention contacts the road surface.

  The directional tread pattern of the tread surface 10 includes a plurality of circumferential grooves 11 that are continuous in the tire circumferential direction and a plurality of lateral grooves 12 that are formed in the tire width direction. Here, the lateral groove 12 located in the vicinity of the tire center 13 is formed between adjacent circumferential grooves 11 and 11, and both ends thereof communicate with the circumferential grooves 11 and 11. Further, the lateral groove 12 located in the vicinity of the tire shoulder 14 is formed between the circumferential groove 11 on the tire center side 13 and the side surface 10 a in the tire width direction of the tread surface 10, and one end thereof communicates with the circumferential groove 11. doing. That is, at least one end of the lateral groove 12 communicates with the circumferential groove 12, and a communication portion 12 a where the lateral groove 12 communicates with the circumferential groove 11 is opened to one side wall surface 11 a of the circumferential groove 12. Has been. Here, the circumferential groove 11 is not limited to a straight shape as shown in FIG. 1, and may be a zigzag shape, that is, a meandering shape.

  A shielding plate 20 is disposed in the circumferential groove 11. As shown in FIGS. 2 and 3-1 to 3, the shielding plate 20 is disposed in the vicinity of the communication portion 12 a in which the lateral groove 12 communicates with the circumferential groove 11. Specifically, the shielding plate 20 is formed integrally with the side wall surface 11a opposite to the tire rotation direction R of the communication portion 12a. An angle θ1 of the shielding plate 20 with respect to the tire circumferential direction (tire rotation direction R) is 90 °. That is, the shielding plate 20 is disposed in the circumferential groove 11 at a right angle to the circumferential groove 11. The thickness L (mm) of the shielding plate 20 varies depending on the shape of the circumferential groove 11 and the rigidity required for the shielding plate 20, but is preferably 5 mm or less.

  The shielding plate 20 includes a horizontal portion 21, an inclined portion 22, and a bottom portion 23. The horizontal portion 21 is integrated on the tire shoulder 14 side in the circumferential groove 11, that is, on one side wall surface 11 a side of the circumferential groove 11. The horizontal portion 21 is formed on the same surface as the surface of a block (not shown) of the tread surface 10. That is, the height of the shielding plate 20 is the same as the circumferential groove depth GD (mm). That is, the shielding plate 20 shields a part of the circumferential groove 11. Here, the width W1 of the horizontal portion 21 is preferably equal to or less than ½ of the circumferential groove width W (mm).

  The inclined portion 22 is formed to be inclined from one end of the horizontal portion 21 to the other side wall surface 11b of the circumferential groove 11, that is, from the tire shoulder 14 side toward the tire center 13 side. Here, the opposite end of the inclined portion 22 to the horizontal portion 22 side, that is, the end portion on the tire center 13 side, is integrated at a predetermined height H (mm) from the other side wall surface 11b and the groove bottom surface 11c. Yes. An opening 24 is formed by the inclined groove 22, the other side wall surface 11 b of the circumferential groove 11, and a road surface (not shown) where the pneumatic tire 1 contacts the ground. Here, the predetermined height H is preferably in a range of 2 mm ≦ H ≦ GD / 2.

  The bottom portion 23 is located below the horizontal portion 21 and the inclined portion 22 and is formed integrally with both the side wall surfaces 11 a and 11 b and the groove bottom surface 11 c of the circumferential groove 11. That is, the shielding plate 20 is formed such that the cross-sectional area BA in the tire width direction increases from the tire shoulder 14 side to the tire center 13 side inward in the tire radial direction. Therefore, since the shielding plate 20 that shields a part of the circumferential groove 11 is disposed in the circumferential groove 11, air column resonance of the circumferential groove 11 can be reduced.

  Further, the shielding plate 20 is supported by both the side wall surfaces 11 a and 11 b and the groove bottom surface 11 c in which the horizontal portion 21 and the bottom portion 23 form the circumferential groove 11. That is, since the shielding plate 20 is supported by the three portions of the side wall surfaces 11a and 11b facing the circumferential groove 11 and the groove bottom surface 11c of the circumferential groove 11, either the side wall surface 11a or the side wall surface 11b and Compared with the shielding plate of the conventional pneumatic tire supported by part or all of the groove bottom surface 11c, the shielding plate 20 is supported more strongly in the circumferential groove 11, and the rigidity of the shielding plate 20 is reduced. This can be suppressed.

  Here, the air column resonance of the circumferential groove 11 occurs in a space formed by the circumferential groove 11 and a road surface (not shown) where the pneumatic tire 1 contacts the ground. On the other hand, the water to be drained in the circumferential groove 11 is water between the circumferential groove 11 and a road surface (not shown) where the pneumatic tire 1 contacts the ground. Therefore, it is preferable that at least one shielding plate 20 is disposed in the ground contact surface S of the pneumatic tire 1. Further, the air column resonance of the circumferential groove 11 occurs particularly in the circumferential groove 11 on the tire center 13 side. Therefore, it is preferable that the shielding plate 20 is disposed at least in the circumferential groove 11 formed on the tire center 13 side in the circumferential groove 11.

  As shown in FIG. 3C, the side surface 25 of the shielding plate 20 opposite to the tire rotation direction R is formed at an angle θ2 on the opposite side of the tire rotation direction R with respect to the tire radial direction. That is, the shielding plate 20 has a hem that extends toward the inside in the tire radial direction so as to be supported by the groove bottom surface 11c of the circumferential groove 11 in a wide area. When the pneumatic tire 1 rotates in the tire rotation direction R, the shielding plate 20 receives a force on the opposite side to the tire rotation direction. Therefore, by making the shielding plate 20 flared toward the tire radial direction, it is possible to reinforce the above-described force, and further suppress the decrease in rigidity of the shielding plate 20. The angle θ2 is preferably 15 ° or more. Further, a side surface (not shown) on the tire rotation direction R side may have an angle larger than 0 ° on the tire rotation direction R side with respect to the tire radial direction. In this case, it is possible to further reinforce the force.

  Next, the movement of water in the circumferential groove 11 of the pneumatic tire 1 according to the present invention will be described. When the pneumatic tire 1 rotates on the wet road surface, water enters the circumferential groove 11 in the range of the ground contact surface S. The water that has entered the circumferential groove 11 moves from the tire rotation direction R side, that is, the front side of the vehicle on which the pneumatic tire 1 is mounted, to the opposite side of the tire rotation direction R, that is, the rear side of the vehicle. At this time, a part of the water in the circumferential groove 11 located on the tire rotation direction R side with respect to the shielding plate 20 is blocked by the shielding plate 20. The water that is not blocked by the shielding plate 20, that is, the water on the tire center 13 side, passes through the opening 24 as shown by an arrow C in FIG.

  On the other hand, the water blocked by the shielding plate 20, that is, the water on the tire shoulder 14 side partially passes through the opening 24 as shown by the arrow D in FIG. Move to the opposite side of the rotation direction R. Other water passes through the communication portion 12a and moves to the lateral groove 12 as indicated by an arrow E in FIG. Here, the shielding plate 20 shields more on the tire shoulder 14 side of the circumferential groove 11, that is, on the communication portion 12 a side where the lateral groove 12 communicates with the circumferential groove 11 than on the tire center 13 side. Therefore, the water (arrow E in FIG. 2) that moves to the horizontal groove 12 among the water blocked by the shielding plate 20 increases, and the water in the circumferential groove 11 can be reliably moved to the horizontal groove 12. When the lateral groove 12 is located in the vicinity of the tire center 13, the water that has moved to the lateral groove 12 moves to the adjacent circumferential groove 11, that is, the circumferential groove 11 on the tire shoulder 14 side as described above. On the other hand, when the lateral groove 12 is positioned in the vicinity of the tire shoulder 14, it is drained to the side surface 11 a of the tread surface 10 of the pneumatic tire 1, that is, outside the ground contact surface S as described above. That is, the water that has moved from the circumferential groove 11 to the lateral groove 12 repeatedly moves from the circumferential groove 11 to the lateral groove 12 and from the lateral groove 12 to the circumferential groove 11, and is finally drained to the outside of the pneumatic tire 1. Thereby, it can suppress that drainage falls.

  In order to achieve both reduction of air column resonance in the circumferential groove 11 and suppression of reduction in drainage, the cross-sectional area BA of the shielding plate 20 in the tire width direction is reduced by the breaking of the circumferential groove 11 in the tire width direction. The area GA is preferably 1/2 to 2/3.

  FIG. 4 is a plan view showing another configuration example of the shielding plate. In the best mode for carrying out the invention, as shown in FIG. 3A, the angle θ1 with respect to the tire circumferential direction of the shielding plate 20 is set to 90 °. However, the invention is not limited to this. The angle θ1 is preferably in the range of 20 ° <θ ≦ 90 °. In particular, as shown in the figure, it is preferable that the angle θ1 is the same as the angle of the lateral groove 12 with respect to the tire circumferential direction. In this case, one of the lateral groove side wall surfaces 12b constituting the lateral groove 12 extends into the circumferential groove 11 as a shielding plate 20 having a constant angle with respect to the tire circumferential direction. Therefore, of the water blocked by the shielding plate 20, the water that moves to the side opposite to the tire rotation direction R indicated by the arrow G becomes more water that moves to the horizontal groove 12 indicated by the arrow F, and the horizontal groove smoothly 12 can be moved. Thereby, it can suppress that drainage falls further.

  FIGS. 5-1 to 5 are front views illustrating other configuration examples of the shielding plate. In the best mode for carrying out the invention, as shown in FIG. 3-2, the shielding plate 20 has a horizontal portion 21, but the invention is not limited to this. For example, as shown in FIG. 5A, a shielding plate 20-1 that does not have the horizontal portion 21 may be used. In this case, the inclined portion 22 extends to one side wall surface 11 a of the circumferential groove 11, the inclined portion 22 is supported by the one side wall surface 11 a, and the inclined portion 22 and the bottom portion 23 form the circumferential groove 11. It will be supported by both the side wall surfaces 11a and 11b and the groove bottom surface 11c.

  Moreover, as shown to FIGS. 3-2, it is not limited to the inclination part 22 of the shielding board 20 being linear, For example, as shown to FIGS. 5-2, the shielding board 20 whose inclination part 22 is curvilinear. -2 may be sufficient. Moreover, as shown to FIGS. 3-2, it is not limited to the edge part by the side of the tire center 13 of the inclination part 22 of the shielding board 20 being integrated with the other side wall surface 11b of the circumferential groove | channel 11, For example, as shown in FIG. 5C, a shielding plate 20-3 in which the end portion of the inclined portion 22 is not integrated with the other side wall surface 11b may be used. Further, as shown in FIG. 3-2, the height of the shielding plate 20 is not limited to be the same as the circumferential groove depth GD. For example, as shown in FIGS. 5-4 and 5-5, The shielding plates 20-4 and 20-5 may be lower than the circumferential groove depth GD.

  Below, the implementation result of the running test with the pneumatic tire of a prior art example and the pneumatic tire concerning this invention is demonstrated. Here, the tire size of each tire used in this running test is 205 / 55R16, and the circumferential groove depth GD and the circumferential groove width W of the circumferential groove 11 are both 8 mm and common. In the running test, each tire was mounted on a 16 × 61 / 2JJ rim, mounted on a 2500 cc passenger car, and the air pressure of each tire was set to 200 kPa. Each item is as follows.

(A) W1: The width (mm) of the horizontal portion 21 of the shielding plate 20.
(B) H: Height (mm) from the groove bottom surface 11 c where the end portion of the inclined portion 22 of the shielding plate 20 is integrated with the other side wall surface 11 b of the circumferential groove 11.
(C) BA / GA: Ratio (%) of the cross-sectional area BA in the tire width direction of the shielding plate 20 to the cross-sectional area GA in the tire width direction of the circumferential groove 11.
(D) Noise performance: According to the method specified in JASO C-606, the sound pressure level (dB) when passing through a section of 10 m at a speed of 60 km / h from the vehicle equipped with each tire. Is measured with a microphone disposed at a position where the distance from the road is 7.5 m and the height from the road surface is 1.2 m. Note that the lower the value, the better the noise performance.
(E) Wet performance: A test course with a water depth of 10 mm and a radius of 100 m is turned, its average speed is measured, and an evaluation is performed with an index where the reciprocal of the measured value of a conventional tire (“conventional example”) is 100. In addition, the higher the numerical value, the better the wet performance.
(F) Failure rate: the rate of occurrence of early wear and breakage of the shielding plate 20
Below, the results of the running test are displayed.

  As apparent from Table 1, the “present invention” which is a pneumatic tire 1 according to the present invention is a conventional tire in which the shielding plate 20 is not disposed in the circumferential groove 11. Compared to “Comparative Example 1”, which is a tire of a comparative example in which a shielding plate that completely shields the directional groove 11 is disposed, a decrease in wet performance is suppressed, and noise performance is improved. In addition, the “invention” has a failure rate with respect to “Comparative Example 2”, which is a comparative tire in which H is 0 mm, that is, the shielding plate is not supported by the other side wall surface 11 b of the circumferential groove 11. Reduced.

  Here, the cross-sectional area BA of the shielding plate 20 in the tire width direction is set to 2/3 or less of the cross-sectional area GA in the tire width direction by the circumferential groove 11 as in “Comparative Example 3”. This is because when it exceeds 2/3, the noise performance is improved, but the wet performance is lowered. Further, the reason why the cross-sectional area BA of the shielding plate 20 in the tire width direction is set to be 1/2 or more of the cross-sectional area GA in the tire width direction of the circumferential groove 11 is that BA / GA is 1 as in “Comparative Example 4”. This is because when it is smaller than / 2, the wet performance is improved, but the noise performance is lowered.

It is a figure which shows the structural example of the pneumatic tire concerning this invention. FIG. 2 is an enlarged perspective view of a portion A in FIG. 1. It is a top view of a shielding board. It is a front view of a shielding board. It is BB sectional drawing of FIGS. It is a top view which shows the other structural example of a shielding board. It is a front view which shows the other structural example of a shielding board. It is a front view which shows the other structural example of a shielding board. It is a front view which shows the other structural example of a shielding board. It is a front view which shows the other structural example of a shielding board. It is a front view which shows the other structural example of a shielding board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 10 Tread surface 11 Circumferential groove | channel 11a, 11b Side wall surface 11c Groove bottom surface 12 Lateral groove 12a Communication part 12b Lateral groove side wall surface 13 Tire center 14 Tire shoulder 20, 20-1-5 Shielding plate 21 Horizontal part 22 Inclined part 23 Bottom 24 Opening 25 Side

Claims (7)

In a pneumatic tire having a tread surface of a directional tread pattern including a plurality of circumferential grooves continuous in the tire circumferential direction and a lateral groove having at least one end communicating with the circumferential groove.
A shielding plate for shielding a part of the circumferential groove in the circumferential groove;
The pneumatic tire according to claim 1, wherein the shielding plate is disposed on a side opposite to a tire rotation direction of a communication portion where the lateral groove communicates with the circumferential groove.   2. The pneumatic tire according to claim 1, wherein the shielding plate is supported by both a side wall surface forming the circumferential groove and a groove bottom surface.   3. The pneumatic tire according to claim 1, wherein a cross-sectional area BA in the tire width direction of the shielding plate increases from the tire shoulder side to the tire center side inward in the tire radial direction.   The pneumatic tire according to any one of claims 1 to 3, wherein at least one of the shielding plates is disposed within a ground contact surface of the pneumatic tire.   The pneumatic tire according to any one of claims 1 to 4, wherein an angle of the shielding plate with respect to a tire circumferential direction is the same as an angle of the lateral groove with respect to the tire circumferential direction.   The pneumatic tire according to claim 1, wherein the shielding plate is disposed at least in a circumferential groove formed on a tire center side in the circumferential groove.   The pneumatic tire according to any one of claims 1 to 6, wherein the shielding plate has a side surface on the opposite side to the tire rotation direction that flares inward in the tire radial direction.

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