JP6092748B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  In a pneumatic tire in which a tread surface is formed with a circumferential groove extending along the tire circumferential direction and a plurality of widthwise grooves opening in the circumferential groove and extending obliquely with respect to the tire circumferential direction. In particular, when wind flows from the width direction groove into the circumferential direction groove during rolling of the tire, an intermediate portion in the tire circumferential direction of the block shape land portion between the width direction grooves (in particular, the tire in the block shape land portion). The position in the tire circumferential direction corresponding to the position 3/4 of the tire circumferential length of the block-shaped land portion from the circumferential one side end to the tire circumferential other side. Winds flowing from both sides of the tire in the circumferential direction may collide and peel outward in the tire radial direction. In this case, even if the tire tread part generates heat and becomes hot during rolling rolling of the tire, the intermediate part in the tire circumferential direction of the block-shaped land part is not sufficiently dissipated, and various failures such as heat separation occur. May occur.

  In view of such a problem, a pneumatic tire in which a recess is formed in a groove wall surface of a circumferential groove facing the width direction groove has been proposed (for example, Patent Document 1). In the pneumatic tire described in Patent Document 1, wind flows from the width direction groove into the circumferential groove when the tire rolls, and both sides of the tire circumferential direction are positioned relatively close to the width direction groove in the circumferential groove. The wind from the wind impinges, and therefore the wind flows in the circumferential groove adjacent to the middle portion of the block-shaped land portion in the tire circumferential direction. Thereby, the intermediate part of the tire circumferential direction of a block-shaped land part is thermally radiated.

JP 2013-86565 A

  However, in the pneumatic tire described in Patent Document 1, the rigidity of the land portion of the tread portion is reduced by the amount of the depression formed on the groove wall surface of the circumferential groove, and as a result, the wear resistance performance and the steering stability performance are lowered. There was a problem of fear.

  This invention makes it a subject to solve the above problems, The place made into the objective is improving the rigidity of a land part, and can obtain the high thermal radiation effect of a tread part. The purpose is to provide tires.

In the first and second pneumatic tires of the present invention, the tire rotation direction R is specified, and at least one circumferential groove extending along the tire circumferential direction is opened on the tread surface, and the circumferential groove is opened. A pneumatic tire formed with a plurality of widthwise grooves extending in a direction inclined with respect to the tire circumferential direction, wherein the widthwise direction of the circumferential groove on the groove wall surface opposite to the widthwise groove A protrusion protruding toward an opening surface of the groove toward the circumferential groove is formed, and a surface on the outer side in the tire radial direction of the protrusion is in the tread surface. According to the pneumatic tire of the present invention, a high heat dissipation effect of the tread portion can be obtained and the rigidity of the land portion can be increased. Note that “projecting toward the opening surface” means projecting toward (opposing to) the opening surface.

  In the pneumatic tire according to the present invention, when the tread tread is viewed in plan, the protruding tips of the protrusions are the connecting edges of the groove wall surfaces of the circumferential grooves with the groove wall surfaces of the circumferential grooves. It is preferable to be disposed between a pair of virtual end surfaces that pass along the tire width direction. Thereby, the heat dissipation effect of the tread portion can be further improved.

  In the pneumatic tire of the present invention, when the tread tread is viewed in plan, the tire from the virtual connection surface that connects the groove wall surfaces of the circumferential grooves located on both sides in the tire circumferential direction of the protrusion to the wall surface of the protrusion It is preferable that the distance in the width direction gradually decreases from the protruding tip of the protrusion toward at least one side in the tire circumferential direction. Thereby, the heat dissipation effect of the tread portion can be further improved.

  In the pneumatic tire of the present invention, when the tread surface is viewed in plan, a virtual connection surface that connects groove wall surfaces of the circumferential grooves located on both sides of the protrusion in the tire circumferential direction, and the wall surfaces of the protrusions Of the two angles formed by the portion adjacent to the virtual connecting surface, it is preferable that one angle be larger than the other angle. Thereby, the heat dissipation effect of the tread portion can be further improved.

In the first pneumatic tire of the present invention, in a plan view the tread surface, the width direction groove, toward from the circumferential groove in the tire width direction outer side, the tire rotated with respect to tire width direction A virtual connection surface that extends in a direction inclined toward the front side in the direction R and connects the groove wall surfaces of the circumferential groove located on both sides of the protrusion in the tire circumferential direction, and a wall surface of the protrusion. Of the two angles, the angle θ1 on the rear side in the tire rotation direction R is the groove wall surface or the virtual connecting surface on the opposite side of the circumferential groove, and the tire rotation direction of the width groove. It is smaller than the angle θ3 on the acute angle side formed by a virtual extended surface obtained by extending the groove wall surface on the front side of R inward in the tire width direction. Thereby, since the flow of the wind from the width direction groove | channel to the circumferential direction groove | channel at the time of load rolling of a tire becomes smoother, the heat dissipation effect of a tread part can further be improved .

In the second pneumatic tire of the present invention, at least one circumferential groove extending along the tire circumferential direction on both sides of the tire width direction with respect to the tire equatorial plane, and the circumferential groove is opened on the tread surface. A plurality of widthwise grooves extending in a direction inclined with respect to the tire circumferential direction are formed, respectively, on both sides of the tire width direction with respect to the tire equatorial plane, on the opposite side of the circumferential groove to the widthwise groove. The groove wall surface is formed with a protrusion protruding toward the opening surface of the width direction groove toward the circumferential groove, and the surface of the protrusion in the tire radial direction is in the tread surface, and the tread surface when viewed in plan, said at tire width direction sides with respect to the tire equatorial plane, wherein the width direction groove, toward from the circumferential groove in the tire width direction outer side, in front of the tire rotation direction R with respect to the tire width direction Extends in a direction inclined at an angle of 30 ° or more toward the wall surface of the projection, projecting in the tire rotation direction R than the projection tip of the force at the rear side, of the tire rotation direction R of the widthwise grooves It includes a portion extending substantially parallel to a virtual extended surface obtained by extending the groove wall surface on the front side inward in the tire width direction. As a result, the amount of wind from the width direction groove to the circumferential direction groove during load rolling of the tire increases, and the flow of this wind becomes smoother, so that the heat dissipation effect of the tread portion can be further improved. it can.

In the pneumatic tire of the present invention, the wall of the pre-Symbol protrusions when viewed in plan the tread surface is projecting at the rear side of the tire rotation direction R than the projection tip of causing the tire rotation direction R of the widthwise grooves It is preferable to include a portion extending along a virtual extended surface obtained by extending the groove wall surface on the front side inward in the tire width direction. In this case, since the flow of wind from the width direction groove to the circumferential direction groove at the time of load rolling of the tire becomes smoother, the heat dissipation effect of the tread portion can be further improved.

  In the pneumatic tire of the present invention, when the tread tread is viewed in plan, the area of the protrusion covers the entire circumference of the tire, and the total area including the protrusion of the circumferential groove in which the protrusion is formed on the groove wall. It is preferable that it exists in 1 to 30% of range. Thereby, while improving the heat dissipation effect of a tread part more appropriately, the rigidity of a land part can be raised more.

  When the tread surface is viewed in plan, the distance in the tire width direction from the virtual connection surface that connects the groove wall surfaces of the circumferential groove located on both sides of the protrusion in the tire circumferential direction to the protruding tip of the protrusion is It is in the range of 30 to 230% with respect to the groove width of the circumferential groove, and the length of the protrusion in the tire circumferential direction is 6 to the length of the circumferential groove of the circumferential groove over the entire circumference of the tire. It is preferably within the range of 26%. Thereby, while improving the heat dissipation effect of a tread part, the rigidity of a land part can be raised more.

  According to this invention, it is possible to provide a pneumatic tire that can obtain a high heat dissipation effect of the tread portion while increasing the rigidity of the land portion.

It is an expanded view of the tread pattern of one embodiment of the pneumatic tire of the present invention. It is a principal part enlarged view of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a figure for demonstrating the modification of the tread pattern of FIG. It is a tire width direction sectional view of one embodiment of the pneumatic tire of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 2 show an embodiment of a pneumatic tire of the present invention (hereinafter sometimes simply referred to as “tire”). The tread pattern described in this embodiment is particularly suitable for pneumatic tires for construction and mining vehicles, but the present invention is also applicable to pneumatic tires used for other types of vehicles. .
In the pneumatic tire of the present invention , the tire rotation direction R is specified, and “one side in the tire circumferential direction” (the lower side in FIG. 1) is the front side in the tire rotation direction R. as the other direction along the side "(upper side in FIG. 1) is the rear side of the tire rotation direction R, to use by mounting the tire on a vehicle.
The tread surface 1 has at least one circumferential groove 2 extending in the tire circumferential direction (in the example shown, two extending on both sides in the tire width direction of the tire equatorial plane CL), and an opening in the circumferential groove 2. A plurality of widthwise grooves 3 extending in a direction inclined with respect to the tire circumferential direction are formed. In the tread surface 1, only one circumferential groove 2 may be formed, or three or more circumferential grooves 2 may be formed.

Here, the tire is mounted on the applicable rim, filled with the specified internal pressure, and between the ground contact ends (both ends in the tire width direction of the ground contact surface; hereinafter referred to as “tread end TE”) when the maximum load is applied. When the tread width, which is the width measured in the tire width direction in that state, is TW, in the present invention, the groove width Wc1 of the circumferential groove 2 is in the range of 0.0025TW ≦ Wc1 ≦ 0.025TW. It is preferable. Furthermore, the opening width Wc2 that is the width in the tire circumferential direction on the opening surface S1 of the widthwise groove 3 to the circumferential groove 2 is preferably in the range of 0.0025TW ≦ Wc2 ≦ 0.025TW. By setting the opening width Wc2 to 0.0025 TW or more, heat dissipation can be ensured, while by setting the opening width Wc2 to 0.025 W, it can be closed at the time of grounding. Therefore, by setting the above range, the wear performance is improved.
“Applicable rim” is an industrial standard effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European Tire and Rim). STANDARDDS MANUAL of Technical Organization, TRA (The Tire and Rim Association, Inc.) YEAR BOOK, etc. in the United States, etc. Rim). The “specified internal pressure” refers to the air pressure corresponding to the maximum load capacity in the applicable size / ply rating described in the above JATMA YEAR BOOK and the like. The “maximum load load” refers to a load corresponding to the maximum load capacity. In this specification, “groove width” refers to the width of a groove measured in a direction perpendicular to the groove width center line.
In this specification, unless otherwise specified, the dimensions (width, angle, etc.) of tire components such as grooves and belts are determined by attaching the tire to the applicable rim, filling the specified internal pressure, The value measured in the state.

  In the illustrated example, the width of the widthwise groove 3 is larger than the width of the circumferential groove 2, but the width of the widthwise groove 3 may be equal to or less than the width of the circumferential groove 2. Moreover, in the example of a figure, although the groove width of the width direction groove | channel 3 is constant over the full length, the groove width of the width direction groove | channel 3 may change in the middle of the extension.

In the example of the figure, the width direction groove 3 has an inclination angle 35 toward the front side (one side in the tire circumferential direction) in the tire rotation direction R with respect to the tire width direction from the circumferential groove 2 toward the outer side in the tire width direction. It extends linearly in a direction inclined at ° and communicates with the tread end TE. However, the width direction groove 3 may extend from the circumferential direction groove 2 toward the inner side in the tire width direction, or may extend toward the rear side in the tire rotation direction R with respect to the tire width direction. It may extend along the direction, may be bent and / or curved at one or more points in the middle of the extension, or may not communicate with the tread end TE.
When the width direction groove 3 extends at an inclination angle of 30 ° or more with respect to the tire width direction as in the example of the figure, the width direction groove 3 and the circumferential direction groove 2 at the time of load rolling of the tire. Since the flow rate of the wind between the two can be significantly increased, the heat dissipation effect of the tread portion can be further improved.
Here, the extending direction of the width direction groove 3 is specifically the direction in which the groove width center line of the width direction groove 3 extends.

  FIG. 2 is an enlarged view of a portion surrounded by a one-dot chain line in FIG. Of the pair of opposed groove wall surfaces of the circumferential groove 2, the groove wall surface on the opposite side to the width direction groove 3 (in the illustrated example, the groove wall surface on the inner side in the tire width direction) is the circumferential direction of each width direction groove 3. A plurality of protrusions 6 that protrude toward the opening surface S <b> 1 to the groove 2 are formed. Here, the protrusion 6 is preferably formed so as not to completely block the circumferential groove 2.

According to the provision of the projection 6, when the wind flows from the width direction groove 3 toward the circumferential groove 2 during load rolling of the tire, the projection 6 causes the wind to move forward in the tire rotation direction R of the circumferential groove 2. It becomes difficult to flow into the side, and most of the wind flows into the rear side of the circumferential direction groove 2 in the tire rotation direction R. And the wind which flows in the circumferential direction groove | channel 2 to the back side of the tire rotation direction R flows to the other protrusion 6 adjacent to the back side of the tire rotation direction R, maintaining strong strength, and before this other protrusion 6 At this point, the tire exits from the circumferential groove 2 outward in the tire radial direction. Thus, at the time of load rolling of the tire, a portion corresponding to an intermediate portion in the tire circumferential direction of the block-shaped land portion 5 in the circumferential groove 2 (for example, an end portion on the front side in the tire rotation direction R of the block-shaped land portion 5) To the rear side of the tire rotation direction R from the position M separated by 3/4 of the tire circumferential length of the block-like land portion 5), and the intermediate portion in the tire circumferential direction of the block-like land portion 5 is effective. Heat can be released. On the other hand, both end portions in the tire circumferential direction of the block-shaped land portion 5 are sufficiently radiated by the strong wind flowing from the width direction groove 3 to the rear side in the tire rotation direction R of the circumferential groove 2.
In addition, since the protrusion 6 is provided, the rigidity of the land portion of the tread portion 1 (specifically, the rib-shaped central land portion 4 between the two circumferential grooves 2) can be increased. Steering stability can be improved.

In the illustrated example, the shape of the protrusion 6 when the tread surface 1 is viewed in plan is a triangular shape. However, as the shape of the protrusion 6 when the tread surface 1 is viewed in plan, for example, any shape such as an arbitrary polygonal shape (rectangular shape, trapezoidal shape, pentagonal shape, etc.), dome shape, Gaussian function shape, etc. Is possible.
Note that “when the tread tread 1 is viewed in plan” means when a development view of the tread pattern on the tread tread 1 is viewed.

In the pneumatic tire of the present invention, as shown in FIG. 2, when the tread tread surface 1 is viewed in plan, the projecting tips 63 of the protrusions 6 are in the circumferential direction of the groove wall surfaces of the widthwise grooves 3 facing each other. It is preferable that they are disposed between a pair of virtual end surfaces S2 and S3 along the tire width direction that pass through the connecting end edges 31 and 32 with the groove wall surface of the groove 2.
Here, the “projection tip 63 of the protrusion 6” refers to the tire width from the groove wall surface of the circumferential groove 2 in which the protrusion 6 is provided among the wall surfaces 64 of the protrusion 6 when the tread tread surface 1 is viewed in plan. It means the part with the maximum directional distance.
With this configuration, most of the wind flowing from the width direction groove 3 toward the circumferential groove 2 is smoothly guided to the rear side in the tire rotation direction R of the circumferential groove 2 by the protrusion 6, and the circumferential groove 2. Since the strong wind that flows toward the rear side in the tire rotation direction R flows to the rear side end portion in the tire rotation direction R of the block-shaped land portion 5, the block-shaped land portion 5 is moved in the tire circumferential direction. Heat can be effectively radiated over the entire length. Therefore, the heat dissipation effect of the tread portion can be further improved.
From the same point of view, as shown in the example of the figure, the protruding tip 63 of the protrusion 6 has a virtual intermediate surface S4 extending in the center of the tire circumferential direction between the pair of virtual end surfaces S2 and S3, and a front side in the tire rotation direction R. More preferably, it is arranged between the virtual end surface S2.
From the same viewpoint, when the tread surface 1 is viewed in plan, as shown in the figure, the protrusion tip 63 of the protrusion 6 is located on the front side in the tire rotation direction R of the width direction groove 3 (one side in the tire circumferential direction). It is also preferable that the groove wall surface is disposed on the virtual extension surface S6 extending inward in the tire width direction, or on the front side in the tire rotation direction R with respect to the virtual extension surface S6. In this case, the wind flowing from the width direction groove 3 toward the circumferential groove 2 is not hindered by the protruding tip 63 of the protrusion 6, so that the wind flow can be made smoother.
Here, the “virtual extension surface S6” is such that the groove wall on the front side in the tire rotation direction R of the width direction groove 3 is connected to the groove wall surface of the circumferential groove 2 when the tread tread 1 is viewed in plan. When it curves in the vicinity of the edge 31, it shall be extended to a tire width direction inner side, keeping the curvature in the connection edge 31 constant.

Further, as shown in FIG. 2, when the tread tread 1 is viewed in plan, the wall surface of the protrusion 6 from the virtual connection surface S5 that connects the groove wall surfaces of the circumferential grooves 2 located on both sides of the protrusion 6 in the tire circumferential direction. The distance in the tire width direction up to 64 is gradually directed toward at least one side in the tire circumferential direction, and particularly preferably gradually from the protruding tip 63 of the protrusion 6 toward the rear side in the tire rotation direction R as shown in FIG. It is preferable to decrease to. According to this, the wind flowing from the width direction groove 3 toward the circumferential groove 2 is guided so as to smoothly flow to the rear side in the tire rotation direction R of the circumferential groove 2 without being peeled outward in the tire radial direction. Therefore, the heat dissipation effect of the tread portion can be further improved.
In addition to or instead of this, as shown in FIG. 2, the distance in the tire width direction from the virtual connection surface S5 to the wall surface 64 of the protrusion 6 is the front of the tire rotation direction R from the protrusion tip 63 of the protrusion 6. It is also preferable to decrease gradually toward the side. According to this, the wind flowing in the circumferential groove 2 toward the rear side in the tire rotation direction R is guided so as to smoothly escape from the circumferential groove 2 outward in the tire radial direction. Can be further improved.

Further, as shown in FIG. 2, when the tread tread 1 is viewed in plan, of the two angles θ <b> 1 and θ <b> 2 formed by the virtual connection surface S <b> 5 and the portion adjacent to the virtual connection surface S <b> 5 of the wall surface 64 of the protrusion 6. One angle (the angle θ2 on the front side in the tire rotation direction R in the example in the figure) is set to be larger than the other angle (the angle θ1 on the rear side in the tire rotation direction R in the example in the figure). preferable.
In this way, the shape of the protrusion 6 when the tread surface 1 is viewed in plan is asymmetric with respect to the tire width direction, so that the wind flowing from the width direction groove 3 toward the circumferential groove 2 is circumferential. It becomes easy to flow toward one side of the tire circumferential direction of the groove 2.
In addition, when the relatively small angle θ1 is formed on the rear side in the tire rotation direction R and the relatively large angle θ2 is formed on the front side in the tire rotation direction R as in the example of the figure, a relatively small angle of the protrusion 6 By the portion forming θ1, the wind flowing from the width direction groove 3 toward the circumferential direction groove 2 flows smoothly to the rear side in the tire rotation direction R of the circumferential direction groove 2 without being peeled outward in the tire radial direction. Be guided to. Further, the portion of the projection that forms a relatively large angle θ2 allows the wind flowing in the circumferential groove 2 toward the rear side in the tire rotation direction R to smoothly escape from the circumferential groove 2 outward in the tire radial direction. Be guided to. Therefore, the heat dissipation effect of the tread portion can be further improved.
Here, “the two angles θ1 and θ2 formed by the virtual connection surface S5 and the portion of the wall surface 64 of the protrusion 6 adjacent to the virtual connection surface S5” means the virtual connection (not the groove wall surface of the circumferential groove 2). It means an angle formed between the surface S5 and a portion of the wall surface 64 of the protrusion 6 adjacent to the virtual connection surface S5, and is not limited to an acute angle, but includes a right angle and an obtuse angle. Further, when the tread surface 1 is viewed in plan, the wall surface 64 of the protrusion 6 is curved in the vicinity of the connecting edges 61 and 62 of the wall surface 64 with the groove wall surface of the circumferential groove 2. , Θ2 are the virtual connecting surface S5 and the connecting end edges 61, 62 to the protruding tip 63 (if the protruding tip 63 extends along the tire circumferential direction, the connecting end edges 61, 62 at the protruding tip 63). Are the angles formed by the drawn line segments (to the closest point to each).

In the example of FIG. 2, when the tread tread 1 is viewed in plan, the tire rotation of two angles θ1 and θ2 formed by the virtual connection surface S5 and the portion adjacent to the virtual connection surface S5 of the wall surface 64 of the protrusion 6 is rotated. The angle θ1 on the rear side in the direction R is formed by the groove wall surface or virtual connection surface S5 (virtual connection surface S5 in the example in the figure) of the circumferential groove 2 opposite to the width direction groove 3 and the virtual extension surface S6. It is smaller than the angle θ3 on the acute angle side. As a result, the wind flowing from the width direction groove 3 toward the circumferential groove 2 is bent twice and then flows in the circumferential groove 2 along the tire circumferential direction, so that the wind is bent only once. Then, it flows into the circumferential groove 2 while being guided smoothly. Therefore, the heat dissipation effect of the tread portion can be further improved.
From a similar viewpoint, when the tread surface 1 is viewed in plan, a portion of the wall surface 64 of the protrusion 6 extending from the protruding tip 63 to the rear side in the tire rotation direction R is at one or more locations on the front side in the tire rotation direction R. The angle at the acute angle between the wall surface 64 and the tire circumferential direction at each bent portion of the wall surface 64 of the protrusion 6 is in a range from the angle θ1 to the angle θ3, It is also preferable that the directional groove 2 is continuously reduced in the order toward the groove wall surface on which the protrusion 6 is formed.

  In addition, when the tread tread 1 is viewed in plan, the area of the protrusion 6 is 1 to 30 with respect to the total area including the protrusion 6 of the circumferential groove 2 formed on the groove wall over the entire circumference of the tire. % Is preferably in the range of%. As a result, a sufficient amount of wind can flow from the width direction groove 3 to the rear side in the tire rotation direction R in the circumferential groove 2, so that the heat dissipation effect of the tread portion can be improved more appropriately and the rigidity of the land portion can be improved. Can be increased.

Further, when the tread surface 1 is viewed in plan, the distance in the tire width direction from the virtual connecting surface S5 to the protruding tip 63 of the protrusion 6 is within a range of 30 to 230% with respect to the groove width of the circumferential groove 2. Preferably there is.
Further, in this case, when the tread surface 1 is viewed in plan, the length of the protrusion 6 in the tire circumferential direction is within a range of 6 to 26% with respect to the length of the circumferential groove 2 over the entire circumference of the tire in the tire circumferential direction. It is preferable that
According to these configurations, the heat dissipation effect of the tread portion can be further improved, and the rigidity of the land portion can be further increased.

  Here, “the area of the protrusion 6”, “the distance in the tire width direction from the virtual connecting surface S5 to the protruding tip 63 of the protrusion 6”, and “the length of the protrusion 6 in the tire circumferential direction” are as shown in the example of the figure. In the case where a plurality of protrusions 6 are formed, the “area of the protrusion 6”, “the distance in the tire width direction from the virtual connecting surface S5 to the protruding tip 63 of the protrusion 6”, “the tire circumferential direction of the protrusion 6” The length of ". Further, “the length of the protrusion 6 in the tire circumferential direction” means a distance in the tire circumferential direction between the connecting edges 61 and 62 of the wall surface 64 of the protrusion 6 and the groove wall surface of the circumferential groove 2. To do.

  In the illustrated example, the connecting edges 61 and 62 of the wall surface 64 of the protrusion 6 and the groove wall surface of the circumferential groove 2 are arranged outside the region between the pair of virtual end surfaces S2 and S3. However, at least one of the connecting end edges 61 and 62 of the wall surface 64 of the protrusion 6 may be disposed between the virtual end faces S2 and S3.

  In the example shown in the figure, the wall surface 64 of the protrusion 6 is formed perpendicular to the groove bottom of the circumferential groove 2. Therefore, the area of the protrusion 6 in the plane parallel to the tread surface 1 is equal to the circumferential direction. It is constant from the opening side of the groove 2 toward the groove bottom side. However, the wall surface 64 of the protrusion 6 may be inclined with respect to the tire radial direction, or may be bent or curved from the opening side of the circumferential groove 2 toward the groove bottom side. Note that the wall surface 64 of the protrusion 6 extends in the tire radial direction so that the area of the protrusion 6 in a plane parallel to the tread surface 1 gradually increases from the opening side of the circumferential groove 2 toward the groove bottom side. In contrast, when the tire is inclined or bent or curved from the opening side of the circumferential groove 2 toward the groove bottom side, it is possible to prevent pebbles or the like from fitting into the circumferential groove 2 during load rolling of the tire. Can do.

  Next, a modified example of the tread pattern of FIG. 1 will be described with reference to FIGS.

  First, the width direction groove | channel 3 is extended in the direction in alignment with a tire width direction from the circumferential direction groove | channel 2 toward a tire width direction outer side in the modification shown in FIGS. In the modified examples shown in FIGS. 21 and 23, 30 ° from the circumferential groove 2 toward the outer side in the tire width direction toward the front side in the tire rotation direction R (one side in the tire circumferential direction) with respect to the tire width direction. It extends in the direction inclined at the above inclination angle (in these modifications, the inclination angle is 35 °).

When the tread surface 1 is viewed in plan, the protruding tip 63 of the protrusion 6 is disposed on the virtual intermediate surface S4 in the modified examples of FIGS. 3, 6, 12, 15, and 16, and FIG. 10, 14, and 17 to 22, they are disposed between the virtual intermediate surface S <b> 4 and the virtual end surface S <b> 2 on the front side in the tire rotation direction R, and FIGS. 4, 5, 7, and 22. 8, 11 and 13 are arranged between the virtual intermediate surface S4 and the virtual end surface S3 on the rear side in the tire rotation direction R. In the modification of FIG. 23, a pair of virtual end surfaces S2, It arrange | positions in the tire rotation direction R front side rather than the area | region between S3.
Further, when the tread surface 1 is viewed in plan, the protruding tip 63 of the protrusion 6 is disposed on the virtual extension surface S6 in the modified examples of FIGS.

  The shape of the protrusion 6 when the tread surface 1 is viewed in plan is a triangular shape in the modified examples shown in FIGS. 3 to 5, 8 to 11, and 13 to 18, and in the modified example of FIG. 6. It is a pentagonal shape, which is a dome shape in the modified examples of FIGS. 7 and 21 to 23, and a rectangular shape in the modified example of FIG. 12. 19, the wall surface 64 of the protrusion 6 when the tread tread 1 is viewed in plan is a portion on the front side in the tire rotation direction R with respect to the protruding tip 63, and protrudes rearward in the tire rotation direction R. It is curved and extends linearly at a portion on the rear side in the tire rotation direction R from the protruding tip 63. 20, the wall surface 64 of the protrusion 6 when the tread tread 1 is viewed in plan is curved convexly toward the rear side in the tire rotation direction R at a portion on the front side in the tire rotation direction R with respect to the projecting tip 63. In addition, at the portion on the rear side in the tire rotation direction R with respect to the protruding tip 63, it is convexly curved toward the front side in the tire rotation direction R.

When the tread tread 1 is viewed in plan, the relationship between the angles θ1 and θ2 on the rear side and the front side in the tire rotation direction R is as shown in FIGS. 18 and 23, θ1 = θ2, and in the variations of FIGS. 5, 9, 10, 14, 15, 21, and 22, θ1 <θ2, and FIG. In the modification examples of FIGS. 11, 17, 19, and 20, θ1> θ2.
3 to 5, FIG. 7 to FIG. 10, FIG. 13 to FIG. 16, and FIG. 20 to FIG. 23 satisfy the relationship of θ1 <θ3 when the tread surface 1 is viewed in plan.

17 to 19, when the tread tread 1 is viewed in plan, the width direction groove 3 is directed forward in the tire rotation direction R with respect to the tire width direction from the circumferential groove 2 toward the outer side in the tire width direction. The wall surface 64 of the protrusion 6 extends toward the side (one side in the tire circumferential direction) at an angle of 30 ° or more, and the wall surface 64 of the protrusion 6 is behind the protruding tip 63 of the protrusion 6 in the tire rotation direction R (the tire circumferential direction). The other side) includes a portion extending substantially parallel to the virtual extension surface S6.
Here, “extending substantially parallel to the virtual extension surface S6” is not illustrated, but the case of extending while maintaining a substantially constant distance from the virtual extension surface S6, and FIGS. In addition to the case where the virtual extension surface S6 extends along the virtual extension surface S6 as in the example, the virtual extension surface S6 includes not only the case where the virtual extension surface S6 extends linearly as in the examples of FIGS. Including the case of extending non-linearly. Even with this configuration, the wind flowing from the width direction groove 3 toward the circumferential direction groove 2 flows smoothly into the circumferential direction groove 2 without peeling off to the outer side in the tire radial direction, thereby further improving the heat dissipation effect of the tread portion. Can be made.
17 to 19, the wall surface 64 of the protrusion 6 includes a portion extending along the virtual extension surface S <b> 6 on the rear side in the tire rotation direction R from the protrusion tip 63 of the protrusion 6. According to this, the wind flowing from the widthwise groove 3 toward the circumferential groove 2 during the load rolling of the tire is not hindered by the protruding tip 63 of the protrusion 6 and flows into the circumferential groove 2 more smoothly. . Therefore, the heat dissipation effect of a high tread part can be acquired.

  In the example of FIG. 1, protrusions 6 having the same shape are formed on both of the two circumferential grooves 2, but when two or more circumferential grooves 2 are provided on the tread surface 1, The protrusion 6 may be formed only in the circumferential groove 2, or the shape of the protrusion 6 may be different for each circumferential groove 2. Further, the shape of the plurality of projections 6 formed in the same circumferential groove 2 may be different for each projection 6.

  Next, with reference to FIG. 24, a tire internal structure in one embodiment of the pneumatic tire of the present invention will be described. In addition, the tire internal structure demonstrated below is applicable to each tire which has a tread pattern demonstrated with reference to FIGS. As shown in FIG. 24, the tire 100 includes a pair of bead cores 110, a carcass 200, and a belt 300 including a plurality of belt layers.

  The bead core 110 is provided in the bead portion 120. The bead core 110 is configured by a bead wire (not shown).

  The carcass 200 forms a skeleton of the tire 100. The position of the carcass 200 passes from the tread portion 500 through the buttress portion 900 and the sidewall portion 700 to the bead portion 120.

  The carcass 200 straddles between the pair of bead cores 110 and has a toroidal shape. The carcass 200 wraps the bead core 110 in this embodiment. The carcass 200 is in contact with the bead core 110. Both ends of the carcass 200 in the tire width direction twd are supported by a pair of bead portions 120.

  The carcass 200 has a carcass cord that extends in a predetermined direction when viewed in plan from the tread surface 1 side. In the present embodiment, the carcass cord extends along the tire width direction twd. For example, a steel wire is used as the carcass cord.

  The belt 300 is disposed on the tread portion 500. The belt 300 is located outside the carcass 200 in the tire radial direction trd. The belt 300 extends in the tire circumferential direction. The belt 300 has a belt cord that is inclined with respect to a predetermined direction that is a direction in which the carcass cord extends. For example, a steel cord is used as the belt cord.

  The belt 300 including a plurality of belt layers includes a first belt layer 301, a second belt layer 302, a third belt layer 303, a fourth belt layer 304, a fifth belt layer 305, and a sixth belt layer 306.

The first belt layer 301 is located outside the carcass 200 in the tire radial direction trd. The first belt layer 301 is located on the innermost side in the belt 300 composed of a plurality of belt layers in the tire radial direction trd. The second belt layer 302 is located outside the first belt layer 301 in the tire radial direction trd. The third belt layer 303 is located outside the second belt layer 302 in the tire radial direction trd. The fourth belt layer 304 is located outside the third belt layer 303 in the tire radial direction trd. The fifth belt layer 305 is located outside the fourth belt layer 304 in the tire radial direction trd. The sixth belt layer 306 is located outside the fifth belt layer 305 in the tire radial direction trd. The sixth belt layer 306 is located on the outermost side in the belt 300 composed of a plurality of belt layers in the tire radial direction trd. In the tire radial direction trd, from the inside toward the outside, the first belt layer 301, the second belt layer 302, the third belt layer 303, the fourth belt layer 304, the fifth belt layer 305, and the sixth belt layer 306 are arranged in this order. Be placed.

  In the present embodiment, in the tire width direction twd, the width of the first belt layer 301 and the second belt layer 302 (the width measured along the tire width direction twd. The same applies hereinafter) is 25% or more of the tread width TW. And it is 70% or less. In the tire width direction twd, the widths of the third belt layer 303 and the fourth belt layer 304 are 55% or more and 90% or less of the tread width TW. In the tire width direction twd, the widths of the fifth belt layer 305 and the sixth belt layer 306 are 60% or more and 110% or less of the tread width TW.

  In the present embodiment, in the tire width direction twd, the width of the fifth belt layer 305 is larger than the width of the third belt layer 303, and the width of the third belt layer 303 is equal to or larger than the width of the sixth belt layer 306. The width of the sixth belt layer 306 is larger than the width of the fourth belt layer 304, the width of the fourth belt layer 304 is larger than the width of the first belt layer 301, and the width of the first belt layer 301 is It is larger than the width of the second belt layer 302. In the tire width direction twd, among the belts 300 composed of a plurality of belt layers, the fifth belt layer 305 has the largest width and the second belt layer 302 has the smallest width. Accordingly, the belt 300 including a plurality of belt layers includes the shortest belt layer (that is, the second belt layer 302) having the shortest length in the tire width direction twd.

  The second belt layer 302 that is the shortest belt layer has a belt end 300e that is an edge in the tire width direction twd.

  In the present embodiment, when viewed from the tread tread surface 1 side, the inclination angle of the belt cords of the first belt layer 301 and the second belt layer 302 with respect to the carcass cord is 70 ° or more and 85 ° or less. The inclination angle of the belt cords of the third belt layer 303 and the fourth belt layer 304 with respect to the carcass cord is not less than 50 ° and not more than 75 °. The inclination angle of the belt cords of the fifth belt layer 305 and the sixth belt layer 306 with respect to the carcass cord is not less than 50 ° and not more than 70 °.

  The belt 300 including a plurality of belt layers includes an inner cross belt group 300A, an intermediate cross belt group 300B, and an outer cross belt group 300C. In each cross belt group 300A to 300C, the belt cords constituting the respective belt layers in the group are between belt layers adjacent to each other in the group (preferably, the tire equator) in a plan view from the tread tread surface 1 side. A group of multiple belt layers that intersect each other (with the plane in between).

  The inner cross belt group 300A includes a pair of belt layers and is located outside the carcass 200 in the tire radial direction trd. The inner cross belt group 300 </ b> A includes a first belt layer 301 and a second belt layer 302. The intermediate cross belt group 300B includes a pair of belt layers and is located outside the inner cross belt group 300A in the tire radial direction trd. The intermediate crossing belt group 300 </ b> B includes a third belt layer 303 and a fourth belt layer 304. The outer cross belt group 300C includes a pair of belt layers and is located outside the intermediate cross belt group 300B in the tire radial direction trd. The outer cross belt group 300 </ b> C includes a fifth belt layer 305 and a sixth belt layer 306.

  In the tire width direction twd, the width of the inner cross belt group 300A is 25% or more and 70% or less of the tread width TW. In the tire width direction twd, the width of the intermediate cross belt group 300B is 55% or more and 90% or less of the tread width TW. In the tire width direction twd, the width of the outer cross belt group 300C is 60% or more and 110% or less of the tread width TW.

  When viewed in plan from the tread surface 1 side, the inclination angle of the belt cord of the inner cross belt group 300A with respect to the carcass cord is not less than 70 ° and not more than 85 °. When viewed from the tread tread 1 side, the inclination angle of the belt cord of the intermediate cross belt group 300B with respect to the carcass cord is not less than 50 ° and not more than 75 °. When viewed in plan from the tread surface 1 side, the inclination angle of the belt cord of the outer cross belt group 300C with respect to the carcass cord is not less than 50 ° and not more than 70 °.

  When viewed in plan from the tread surface 1 side, the inclination angle of the belt cord with respect to the carcass cord is the largest inclination angle of the inner cross belt group 300A. The inclination angle of the belt cord with respect to the carcass cord of the intermediate intersection belt group 300B is equal to or greater than the inclination angle of the belt cord with respect to the carcass cord of the outer intersection belt group 300C.

  The circumferential groove 2 is along the tire width direction twd from the belt end 300e to the groove width center line WL passing through the center in the width direction of the circumferential groove 2 when viewed from the tread tread surface 1 side of the tire 100. The length DL is formed to be 200 mm or less.

  When each tire having the tread pattern described with reference to FIGS. 1 to 23 includes the above-described belt 300, the inner cross belt group 300A that easily generates heat at the time of load rolling of the tire has a tread pattern. Due to the excellent heat dissipation effect in the tread portion exhibited by the configuration, the heat is radiated well. This prevents damage to the inner cross belt group 300A due to heat generation in particular.

  In order to confirm the effect of the present invention, the tire of Comparative Example 1 and the tires of Examples 1 to 9 were made on a trial basis. The specifications of each tire are shown in Table 1 below. The tires of Comparative Example 1 and Examples 1 to 9 have the same tread pattern as the examples of FIGS. 1 and 2. However, in the tire of Comparative Example 1, the protrusion 6 is not formed on the groove wall surface of the circumferential groove 2. On the other hand, in the tires of Examples 1 to 9, as in the example of FIG. 2, the opening surface to the circumferential groove 2 of the width direction groove 3 is formed on the groove wall surface of the circumferential direction groove 2 opposite to the width direction groove 3. A projection 6 having a triangular shape in a plan view of the tread surface 1 is formed. In the tires of Examples 1 to 9, the protruding tip 63 of the protrusion 6 rotates from the connecting edge 61 on the front side in the tire rotation direction R with the groove wall surface of the circumferential groove 2 of the wall surface 64 of the protrusion 6. On the rear side in the direction R, the tire 6 is located at a position in the tire circumferential direction separated by 3/10 of the length in the tire circumferential direction of the protrusion 6. In the tires of Examples 1 to 9, the protruding tip 63 is not necessarily on the virtual extension surface S6.

  In Table 1, “protrusion width” refers to the distance in the tire width direction from the virtual connection surface S5 that connects the groove wall surfaces of the circumferential grooves 2 located on both sides of the protrusion 6 in the tire circumferential direction to the protruding tip 63 of the protrusion 6. It is. The “circumferential groove width” is the groove width of the circumferential groove 2. The “projection length” is the length of the projection 6 in the tire circumferential direction. The “circumferential groove length” is the length in the tire circumferential direction of the circumferential groove 2 over the entire circumference of the tire. The “projection area” is a calculated value of (projection length) × (projection width) / 2. The “circumferential groove area” is a calculated value of (circumferential groove width) × (circumferential groove length).

  Each tire of Comparative Example 1 and Examples 1 to 9 was incorporated into a rim, filled with a specified internal pressure, mounted on a vehicle, and tested to evaluate tire life. In this evaluation test, the tire life of Examples 1 to 9 was relatively evaluated with the evaluation result of the comparative example tire 1 being 100 (index). In Table 1, the higher the tire life index, the longer the tire life.

  As shown in Table 1, it can be seen that the tires according to Examples 1 to 9 all have improved tire life. Therefore, according to the pneumatic tire of the present invention, it was confirmed that a high heat dissipation effect of the tread portion was obtained, thereby improving the tire life.

  The present invention can be used for pneumatic tires for construction and mining vehicles, for example.

1: tread surface, 2: circumferential groove, 3: width direction groove, 4: rib-shaped central land portion, 5: block-shaped land portion, 6: protrusion, 31, 32: circumferential direction of the groove wall surface of the width direction groove 61, 62: connection edge of the protrusion wall surface with the groove wall surface of the circumferential groove, 63: protrusion protrusion tip, 64: protrusion wall surface, 100: tire, 120: Bead part, 200: carcass, 300: belt, 301: first belt layer, 302: second belt layer, 303: third belt layer, 304: fourth belt layer, 305: fifth belt layer, 306: sixth Belt layer, 300A: inner cross belt group, 300B: intermediate cross belt group, 300C: outer cross belt group, 300e: belt end, 500: tread part, 700: sidewall part, 900: buttress part, CL: tire equatorial plane , R : Tire rotation direction, S1: opening surface, S2, S3: virtual end surface, S4: virtual intermediate surface, S5: virtual connecting surface, S6: virtual extension surface, TE: tread end

Claims (8)

A tire rotation direction R is specified, at least one circumferential groove extending along the tire circumferential direction on the tread surface, and a plurality of widths that open in the circumferential groove and extend in a direction inclined with respect to the tire circumferential direction A pneumatic tire formed with a directional groove,
On the groove wall surface of the circumferential groove opposite to the width direction groove, a protrusion protruding toward the opening surface to the circumferential groove of the width direction groove is formed,
The outer surface of the projection in the tire radial direction is in the tread surface,
When the tread tread is viewed in plan,
The width direction groove extends from the circumferential groove toward the outer side in the tire width direction in a direction inclined toward the front side of the tire rotation direction R with respect to the tire width direction,
Of the two angles formed by the virtual connection surface connecting the groove wall surfaces of the circumferential grooves located on both sides of the protrusion in the tire circumferential direction and the wall surface of the protrusion, an angle θ1 on the rear side in the tire rotation direction R is A virtual wall surface or the virtual connecting surface of the circumferential groove opposite to the width direction groove, and a virtual wall surface extending inward in the tire width direction of the groove wall on the front side in the tire rotation direction R of the width direction groove. A pneumatic tire characterized by being smaller than an angle θ3 on the acute angle side with the surface. A tire rotation direction R is designated, and at least one circumferential groove extending along the tire circumferential direction on both sides in the tire width direction with respect to the tire equatorial plane and an opening in the circumferential groove on the tread tread surface, and in the tire circumferential direction. A plurality of widthwise grooves extending in a direction inclined with respect to each other is a pneumatic tire formed,
On both sides of the tire equatorial plane in the tire width direction,
On the groove wall surface of the circumferential groove opposite to the width direction groove, a protrusion protruding toward the opening surface to the circumferential groove of the width direction groove is formed,
The outer surface of the projection in the tire radial direction is in the tread surface,
When the tread tread is viewed in plan, on both sides of the tire equatorial plane in the tire width direction,
The width direction groove extends from the circumferential groove toward the outer side in the tire width direction in a direction inclined at an angle of 30 ° or more toward the front side of the tire rotation direction R with respect to the tire width direction,
A virtual extension surface in which the wall surface of the protrusion extends rearward in the tire rotation direction R from the protruding tip of the protrusion and the groove wall surface on the front side in the tire rotation direction R of the width direction groove extends inward in the tire width direction; A pneumatic tire comprising a portion extending substantially in parallel.   When the tread surface is viewed in plan, a pair of protrusions along the tire width direction in which the protruding tips of the protrusions pass through the connecting edges of the groove wall surfaces of the circumferential grooves with the groove wall surfaces of the circumferential grooves. The pneumatic tire according to claim 1, wherein the pneumatic tire is disposed between the virtual end faces.   When the tread tread is viewed in plan, the distance in the tire width direction from the virtual connecting surface that connects the groove wall surfaces of the circumferential groove located on both sides of the protrusion in the tire circumferential direction to the wall surface of the protrusion is the protrusion. The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire gradually decreases from the protruding tip of the tire toward at least one side in the tire circumferential direction.   A virtual connection surface that connects the groove wall surfaces of the circumferential grooves located on both sides in the tire circumferential direction of the protrusion when the tread surface is viewed in plan, and a portion of the protrusion wall surface adjacent to the virtual connection surface; The pneumatic tire according to any one of claims 1 to 4, wherein one of the two angles is greater than the other angle. When the tread tread is viewed in plan,
The wall surface of the protrusion is a virtual extension surface that extends inward in the tire width direction of the groove wall surface on the front side of the tire rotation direction R of the width direction groove on the rear side in the tire rotation direction R from the protrusion tip of the protrusion. The pneumatic tire according to claim 2, comprising a portion extending along the pneumatic tire. When the tread tread is viewed in plan,
The area of the said protrusion exists in the range of 1-30% with respect to the total area including the said protrusion of the said circumferential groove | channel where the said protrusion was formed in the groove wall over the tire circumference. The pneumatic tire according to any one of the above. When the tread tread is viewed in plan,
The distance in the tire width direction from the virtual connection surface that connects the groove wall surfaces of the circumferential groove located on both sides of the protrusion in the tire circumferential direction to the protruding tip of the protrusion is 30 with respect to the groove width of the circumferential groove. In the range of ~ 230%,
The length in the tire circumferential direction of the protrusion is in the range of 6 to 26% with respect to the length in the tire circumferential direction of the circumferential groove over the entire circumference of the tire. The described pneumatic tire.

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