JP2022057793A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire capable of inhibiting stone trapping while securing drainage performance and riding comfort without significantly damaging other maneuverability.SOLUTION: A pneumatic tire in this invention has: one or more circumferential main grooves extending in a tread circumferential direction on a tread; and plural width-directional sipes extending in a tread width direction, and plural pin-like sipes on a width-directional outermost side land part on one side of the tread width direction partitioned by a tread edge and the circumferential main groove. The pin-like sipes are each arranged on an extended line of the width-directional sipe without communicating with the width-directional sipe. The pin-like sipes are arranged at intervals in the tread circumferential direction in only one row. The pin-like sipes are arranged on an outer side in a tire width direction with respect to a midpoint in the tread width direction of the width-directional outermost side land part. The width-directional outermost side land part has no circumferential sipe extending in the tread circumferential direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pneumatic tire.

For pneumatic tires, it is desired to improve drainage. For example, in Patent Document 1, a pin-shaped sipe is provided in a part of an extending region of a widthwise sipe extending in the tread width direction, and water between the tire and the road surface may enter the pin-shaped sipe. It makes it possible to improve drainage. Further, by providing the pin-shaped sipes, the edge component in the width direction is reduced as compared with the case where the drainage property is improved by the width direction sipes, so that the riding comfort can be improved.

Japanese Unexamined Patent Publication No. 2017-193222

However, in the technique described in Patent Document 1, the rigidity of the land portion may be lowered and the kinetic performance such as steering stability may be lowered. In addition, there is a concern that stone bites may occur in the vicinity of pin-shaped pavements, such as stones on the road surface.

Therefore, an object of the present invention is to provide a pneumatic tire that can suppress stone biting without significantly impairing other kinetic performance while ensuring drainage and riding comfort.

The gist structure of the present invention is as follows.
(1) The tread of the tread portion has one or more circumferential main grooves extending in the circumferential direction of the tread.
A plurality of widthwise sipes extending in the width direction of the tread and a plurality of pin-shaped sipes are provided in the outermost land portion in the width direction on one side in the width direction of the tread, which is partitioned by the tread end and the main groove in the circumferential direction. death,
The pin-shaped sipe is arranged on an extension of the width sipe without communicating with the width sipe.
The pin-shaped sipes consist of only one row spaced apart in the tread circumferential direction.
The pin-shaped sipes are arranged outside the tire width direction from the midpoint in the tread width direction of the outermost land portion in the width direction.
A pneumatic tire, characterized in that the outermost land portion in the width direction does not have a circumferential sipe extending in the circumferential direction of the tread.

Here, the "tread surface" refers to the entire area of the tread circumferential direction of the ground contact surface that comes into contact with the road surface when a pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and the maximum load is applied.
Further, the "tread end" means both ends of the ground plane in the tread width direction.
The "main groove in the circumferential direction" is a groove width (opening width) of 2 mm or more when the tire extends in the circumferential direction of the tread, a pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and no load is applied. To say. The "circumferential sipe" refers to a tire having a groove width (opening width) of less than 2 mm when the tread extends in the circumferential direction, a pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and no load is applied. "Main groove in the circumferential direction" and "sipe in the circumferential direction" are "extended in the circumferential direction of the tread" when they extend in the circumferential direction of the tread (inclination angle with respect to the circumferential direction of the tread is 0 °) and 5 ° with respect to the circumferential direction of the tread. The case of extending at the following inclination angles is also included.
Further, the "width direction groove" described later is a groove width (opening width) of 2 mm or more when the tire extends in the tread width direction, a pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and no load is applied. Say something. The "width direction sipe" means a tire having a groove width (opening width) of less than 2 mm when the tire extends in the tread width direction, a pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and no load is applied.

The above "applicable rim" is an industrial standard that is effective in the area where tires are produced and used. In Japan, JATTA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European Tire and Rim). STANDARDS MANUAL in Technical Organization, YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States, etc. , TRA's YEAR BOOK (DesignRim) (ie, the "applicable rim" above includes sizes that may be included in the industry standards in the future in addition to the current size. As an example, the size described as "FUTURE DEVELOPMENTS" in the STANDARDS MANUAL 2013 edition of ETRTO can be mentioned.) However, if the size is not described in the above industrial standard, it corresponds to the bead width of the tire. A rim with a wide width.
The "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size and ply rating described in the above-mentioned JATMA YEAR BOOK and the like, and is described in the above-mentioned industrial standard. In the case of no size, "specified internal pressure" means the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle equipped with tires. Further, the "maximum load" means a load corresponding to the above maximum load capacity. The air referred to here can be replaced with an inert gas such as nitrogen gas or the like.

(2) The pneumatic tire according to (1) above, wherein the outermost land portion in the width direction on one side in the tread width direction is the inner land portion when mounted on a vehicle.

(3) The pneumatic tire according to (1) or (2) above, wherein the pin-shaped sipes are arranged only on the outermost land portion in the width direction on one side in the tread width direction.

(4) It has two or more of the circumferential main grooves and has two or more main grooves in the circumferential direction.
In the first central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on one side in the tread width direction, the inside of the first central land portion. A first having a first narrowed neck portion that communicates the first air chamber portion terminated with a tire and the circumferential main groove on the outer side of the first central land portion in the tire width direction with the first air chamber portion. Multiple resonators are arranged,
In the plan view, the groove width of the first air chamber gradually increases from one side in the tread circumferential direction to the other side.
The pneumatic tire according to any one of (1) to (3) above, wherein the first narrowed neck portion communicates with an end portion of the first air chamber portion on one side in the tread circumferential direction.

(5) The air according to (4) above, wherein the first narrowed neck portion has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width at the opening to the tread. Tires with.

(6) It has two or more of the circumferential main grooves and has two or more main grooves in the circumferential direction.
Any of the above (1) to (5), wherein the groove width of the circumferential main groove located on the other side in the tread width direction is larger than any of the other circumferential main grooves. Pneumatic tires listed in.

(7) The pneumatic tire according to any one of (4) to (6) above, wherein the first air chamber portion extends along the circumferential direction of the tread.

(8) Having two or more of the circumferential main grooves,
In the second central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the outermost land portion in the width direction on the other side in the tread width direction, which is partitioned by the tread end and the circumferential main groove. A plurality of second resonators having a second air chamber terminated in the second central land portion and a second narrowed neck portion communicating the circumferential main groove with the second air chamber. Placed,
The second air chamber portion has a central portion on the central side in the tread width direction and two raised side portions adjacent to the groove walls on both sides in the tread width direction.
The central portion has a first bottom-raised portion on the central side in the circumferential direction of the tread, which is raised from the end side in the tread width direction.
The pneumatic tire according to (7) above, wherein each of the two side portions has a second bottom-raised portion on the central side in the circumferential direction of the tread, which is raised from the end side in the tread width direction.

(9) The air according to (8) above, wherein the second narrowed neck portion has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width at the opening to the tread. Tires with.

(10) Having two or more of the circumferential main grooves,
Any of the above (1) to (9), wherein the outermost land portion in the width direction on the other side in the width direction of the tread, which is partitioned by the tread end and the main groove in the circumferential direction, does not have a circumferential sipe extending in the circumferential direction of the tread. Pneumatic tires listed in.

(11) Having two or more of the circumferential main grooves,
A second central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the outermost land portion in the width direction on the other side in the tread width direction, which is partitioned by the tread end and the circumferential main groove, The pneumatic tire according to any one of (1) to (10) above, which does not have a circumferential sipe extending in the circumferential direction of the tread.

(12) It has three or more of the circumferential main grooves, and has three or more main grooves in the circumferential direction.
In the first central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on one side in the tread width direction, the inside of the first central land portion. A first having a first narrowed neck portion that communicates the first air chamber portion terminated with a tire and the circumferential main groove on the outer side of the first central land portion in the tire width direction with the first air chamber portion. Multiple resonators are arranged,
In the second central land portion, which is partitioned between the two main grooves in the circumferential direction and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on the other side in the tread width direction, the inside of the second central land portion. A second having a second narrowed neck portion that communicates the second air chamber portion terminated with a tire and the circumferential main groove on the outer side of the second central land portion in the tire width direction with the second air chamber portion. Multiple resonators are arranged,
The plurality of the first resonators and the plurality of the second resonators are the first air chamber portion and the first resonator when viewed in the tread width direction at any position in the tread circumferential direction. The pneumatic tire according to any one of (1) to (11) above, which is arranged so that either or both of the two air chambers are present.

According to the present invention, it is possible to provide a pneumatic tire that can suppress stone biting without significantly impairing other kinetic performance while ensuring drainage and riding comfort.

It is a tread development view which shows the tread surface of the tread part of the tire which concerns on one Embodiment of this invention. It is an enlarged view of the 2nd resonator and the circumferential main groove. It is sectional drawing of the 2nd narrowing neck part. It is an enlarged view of the 2nd air chamber part. It is sectional drawing of the 2nd air chamber part. It is a plan view and a cross-sectional view of a pin-shaped sipe.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, when the dimensions of the components are described, unless otherwise specified, the dimensions are the dimensions when the pneumatic tire is attached to the applicable rim, the specified internal pressure is applied, and no load is applied.

Since the internal structure of the pneumatic tire of the present invention (hereinafter, also simply referred to as “tire”) can have the same configuration as the conventional one, the description thereof will be omitted. As an example, a pair of bead portions may be provided with a carcass straddling a toroidal shape, and a belt and a tread portion arranged on the outer side of the carcass in the tire radial direction.

FIG. 1 is a tread development view showing a tread surface of a tread portion of a tire according to an embodiment of the present invention. As shown in FIG. 1, this tire has one or more (three in the illustrated example) circumferential main grooves 2 (2a, 2b, 2c) extending in the circumferential direction of the tread on the tread surface 1 of the tread portion.

Then, the land portion 3 (3a, 3b, 3c, 3d) (4 in the illustrated example) is partitioned between the tread end TE and the circumferential main groove 2 or between the circumferential main grooves 2. That is, the outermost land portion 3a in the width direction on one side in the tread width direction is partitioned by the tread end TE on one side in the tread width direction and the main groove 2a in the circumferential direction, and the tread end TE on the other side in the tread width direction. And the circumferential main groove 2c divides the outermost land portion 3d in the width direction on the other side in the tread width direction. Further, a first central land portion 3b adjacent to the inner side in the tread width direction of the outermost land portion 3a in the width direction on one side in the tread width direction is partitioned between the main grooves 2a and 2b in the circumferential direction. A second central land portion 3c adjacent to the inner side of the outermost land portion 3d in the width direction on the other side in the tread width direction in the tread width direction is partitioned between the directional main grooves 2b and 2c.
In the illustrated example, the second central land portion 3c is located on the tire equatorial plane CL, the circumferential main grooves 2a and 2b are located in the tread half portion on one side in the tread width direction, and the circumferential main groove 2c is located. Is located in the half of the tread on the other side in the tread width direction. On the other hand, the present invention is not limited to this case, and for example, the circumferential main groove may be located on the tire equatorial plane CL.
In the illustrated example, each land portion 3 is a rib-shaped land portion (a land portion in which the land portion is not completely divided in the tread circumferential direction by the width direction groove), but any land portion 3 is regarded as a block shape. Is also good. In this specification, even if the land portion is completely divided in the tread circumferential direction by the width direction sipes, it is included in the rib-shaped land portion.
The tire of the illustrated example is configured so that one side in the tread width direction can be the inside when the vehicle is mounted, and the other side in the tread width direction can be the outside when the vehicle is mounted.
The number of the circumferential main grooves 2 is not limited to three, and may be, for example, four. Therefore, the number of land portions 3 is not limited to four, and may be, for example, five.

The groove width (opening width) of the circumferential main groove 2 is not particularly limited, but can be 10 to 14 mm, and the groove depth (maximum depth) of the circumferential main groove 2 is particularly limited. Although not, it can be 5 to 9 mm. Further, the groove width of the circumferential main groove (circumferential main groove 3c in the illustrated example) located on the other side in the tread width direction on the outermost side in the width direction is the other circumferential main groove (circumferential main groove 3a in the illustrated example). It is preferably larger than any of the groove widths in 3b). Further, in the illustrated example, any of the circumferential main grooves 2 extends straight in the tread circumferential direction, but may extend in a zigzag shape, a curved shape, or a bent shape in the tread circumferential direction.

The magnitude relationship of the width in the tread width direction of the land portion 3 is not particularly limited, but for example, as shown in the figure, the width in the tread width direction of the first central land portion 3b is the tread width of the second central land portion 3c. It is preferably smaller than the width in the direction. When one side in the tread width direction is inside when mounted on the vehicle, the rigidity of the outside when mounted on the vehicle (which greatly contributes to steering stability) is relatively high, and the inside when mounted on the vehicle (which contributes greatly to ride comfort) is relatively high. This is because by making the rigidity of the tire relatively low, it is possible to effectively achieve both steering stability and ride comfort.

As shown in FIG. 1, the land portion 3a has a plurality of widthwise sipes 4 extending in the tread width direction and a plurality of pin-shaped sipes 5. On the other hand, the land portion 3a does not have a circumferential sipe extending in the circumferential direction of the tread. Further, the land portion 3a does not have a groove in the width direction.

The land portion 3a extends outward in the tread width direction from the first width direction sipe 4a and the circumferential main groove 2a communicating from the tread end TE to the circumferential main groove 2a as the width direction sipe 4, and is the land portion. It has two types of widthwise sipes 4: a second widthwise sipes 4b, which terminates within 3a (near the widthwise center of the land portion 3a in the illustrated example). Then, the first width direction sipes 4a and the second width direction sipes 4b are alternately arranged in the tread circumferential direction. The first and second width direction sipes 4a and 4b are not particularly limited, but extend in the tread width direction (inclination angle 0 °) or incline at an inclination angle of 45 ° or less with respect to the tread width direction. Can be done. Further, in the illustrated example, the first and second widthwise sipes 4a and 4b do not have a bent portion, but may have a bent portion. The sipe width (opening width) of the width direction sipes 4a and 4b is not particularly limited, but can be 0.5 to 2 mm, and the sipe depth (maximum depth) of the width direction sipes 4a and 4b is particularly limited. Is not limited, but can be 3 to 9 mm. The first width direction sipe 4a does not necessarily have to be provided.

FIG. 4 is a plan view and a cross-sectional view of the pin-shaped sipe. As shown in FIG. 4, the pin-shaped sipe 5 is a small-diameter hole whose opening is circular in a plan view. The diameter of the hole (maximum diameter of the opening) is such that the wall surfaces do not come into contact with each other when the tire is attached to the applicable rim, the specified internal pressure is applied, and the maximum load is applied. Specifically, the diameter of the hole can be 2 to 6 mm, although it is not particularly limited. By setting the diameter of the hole to 2 mm or more, the effect of improving drainage can be further exerted, and on the other hand, by setting the diameter of the hole to 6 mm or less, the rigidity of the land portion can be prevented from being lowered as much as possible. The depth of the hole is not particularly limited, but may be 3 to 9 mm. By setting the hole depth to 3 mm or more, the effect of improving drainage can be further exerted, while by setting the hole depth to 9 mm or less, the rigidity of the land portion can be prevented from being lowered as much as possible. .. The pin-shaped sipe 5 has an opening that is circular in a plan view, which is suitable for suppressing the occurrence of cracks in the sipe 5, but it can also have an elliptical shape or a polygonal shape. .. Further, the diameter of the hole can be constant in the depth direction of the hole, or can be changed (for example, gradually decreasing or gradually increasing) from the opening side toward the bottom side of the sipe. For example, a diameter-expanded portion (preferably having a maximum diameter of 1.5 to 3 times the diameter of the opening of the sipe) may be provided at the position of the bottom of the sipe (preferably 80% to 100% of the depth of the sipe). can. Further, the sipe bottom of the pin-shaped sipe 5 can be rounded in order to suppress the occurrence of cracks at the sipe bottom. In the example shown in FIG. 4, the diameter is constant from the opening to about half of the groove depth, and then the diameter gradually decreases toward the bottom of the sipe.

Further, the pin-shaped sipes 5 are arranged on an extension line of the width direction sipes 4b without communicating with the width direction sipes 4b. The "extension line" shall be a straight line connecting the outer end of the tread width direction of the width direction sipe and the point 1 mm inside along the periferi of the width direction sipe, and "arranged on the extension line". The term includes the case where the pin-shaped sipe portion and the straight line intersect, or the shortest distance between the pin-shaped sipe portion and the straight line is 0.5 m or less. Further, the pin-shaped sipes 5 consist of only one row arranged at intervals in the tread circumferential direction (in the illustrated example, a plurality of pin-shaped sipes 5 are located at the same position in the tread width direction in the tread circumferential direction). They are arranged at approximately equal intervals). Further, the pin-shaped sipes 5 are arranged outside the tire width direction from the midpoint in the tread width direction of the outermost land portion 3a in the width direction. The pin-shaped sipes 5 are arranged only in the outermost land portion 3a in the width direction on one side in the tread width direction, and are not arranged in the other land portions 3b, 3c, and 3d.

Next, in the first central land portion 3b, the first air chamber portion 6a terminated at the first central land portion 3b and the circumferential main groove on the outer side in the tire width direction of the first central land portion 3b. A plurality of first resonators 6 having a first narrowed neck portion 6b communicating the 2a and the first air chamber portion 6a are arranged in the circumferential direction of the tread. In this example, the first resonator 6 is a Helmholtz type resonator.

In this example, the first air chamber portion 6a extends along the tread circumferential direction from one side in the tread circumferential direction (upper side in the figure) to the other side in the tread circumferential direction (lower side in the figure). More specifically, the first air chamber portion 6a has a shape in which the length in the tread circumferential direction projected in the tread width direction is longer than the length in the tread width direction projected in the tread circumferential direction. For example, the ratio of the length in the tread circumferential direction to the length in the tread width direction can be 2 to 4. The groove volume of the first air chamber portion 6a is larger than the groove volume of the first narrowed neck portion 6b. The specific volume can be appropriately adjusted according to the frequency band of the sound that the first resonator 6 is expected to reduce. In this example, the first air chamber portion 6a has a substantially triangular shape in which the groove width gradually increases from one side in the tread circumferential direction toward the other side in a plan view. The shape of the first air chamber portion 6a is not limited to this shape, and can be various shapes so as to exhibit the function as a resonator.

In the illustrated example, the first narrowed neck portion 6b communicates with the circumferential main groove 2a on the TE side of the tread end, but can also communicate with the circumferential main groove 2b on the tire equatorial surface CL side. Further, in this example, the first narrowed neck portion 6b communicates with one end of the first air chamber portion 6a in the circumferential direction of the tread. Alternatively, the first constricted neck portion 6b can communicate with the other end of the first air chamber portion 6a in the circumferential direction of the tread. The groove width (opening width) of the narrowing neck portion 6b is not particularly limited, but is preferably 0.4 to 1.2 mm, for example, and if the groove width is 0.4 mm or more, the first narrowing at the time of touchdown. The function of the first resonator 6 can be exerted by preventing the neck portion 6a from closing, while the land portion around the first narrowed neck portion 6b if the groove width is 1.2 mm or less. Rigidity can be ensured and uneven wear can be suppressed. For the same reason, the groove width of the first narrowed neck portion 6 is more preferably 0.5 to 0.7 mm. Further, the first narrowed neck portion 6b has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width (opening width) at the opening to the tread surface 1. This makes it possible to improve the drainage property when wear progresses. On the other hand, the first narrowed neck portion 6b may not have a diameter-expanded portion on the groove bottom side. The enlarged diameter portion is preferably provided at a position of 80% to 100% of the groove depth, and preferably has a maximum diameter of 1.5 to 3 times the opening width.

Further, in the first central land portion 3b, a plurality of third widths extending inward in the tread width direction from the circumferential main groove 2b on the tire equatorial plane CL side and ending in the first central land portion 3b. Directional sipes 7 are also formed (at intervals in the circumferential direction of the tread). As a result, it is possible to increase the edge component in the width direction and improve the kinetic performance such as the traction performance. The third width direction sipe 7 does not communicate with the first resonator 6. The sipe width (opening width) of the third width direction sipe 7 is not particularly limited, but may be 0.2 to 1 mm, and the sipe depth (maximum depth) of the third width direction sipe 7 may be 0.2 to 1 mm. However, the thickness is not particularly limited, but may be 2 to 6 mm. The first central land portion 3b does not have a circumferential sipe extending in the circumferential direction of the tread. Further, the first central land portion 3b does not have a groove in the width direction.

Next, in the second central land portion 3c, a second air chamber portion 8a and a circumferential main groove 2b (2c) and a second air chamber portion 8a terminated in the second central land portion 3c are provided. A plurality of second resonators 8 having a second narrowed neck portion 8b (8c) communicating with each other (two for each second air chamber portion 8b in this example) are arranged in the tread circumferential direction. ing. In this example, the second resonator 8 is a Helmholtz type resonator. In the illustrated example, the second resonator 8 has two types of narrowed neck portions, one narrowed neck portion 8b communicates with the circumferential main groove 2b on the CL side of the tire equatorial plane, and the other narrowed neck portion. 8c communicates with the circumferential main groove 2c on the TE side of the tread end. As a result, the second resonator 8 can exert a reducing effect on both the sound generated in the circumferential main groove 2b and the sound generated in the circumferential main groove 2c. On the other hand, the narrowed neck portion may be communicated only with one of the circumferential main grooves (in this case, for example, one narrowed neck portion can be provided for one air chamber portion). The second central land portion 3c does not have a circumferential sipe extending in the circumferential direction of the tread. Further, the second central land portion 3c does not have a groove in the width direction.

FIG. 2A is an enlarged view showing the second resonator and the circumferential main groove in FIG. 1 extracted.
As shown in FIG. 2A, the second air chamber portion 8a includes a central portion 8a1 on the central side in the tread width direction and two raised side portions 8a2 and 8a3 adjacent to the groove walls on both sides in the tread width direction, respectively. ,have. In the illustrated example, the groove width of the central portion 8a1 gradually increases from the end portion on one side in the tread circumferential direction toward the central portion side in the tread circumferential direction, and the groove width gradually increases from the central portion side in the tread circumferential direction to the other side in the tread circumferential direction. The width of the groove gradually decreases toward the end. Further, in the illustrated example, the side portion 8a2 on the circumferential main groove 2c side extends in the tread circumferential direction from the end side on one side of the central portion 8a1 in the tread circumferential direction to the vicinity of the center of the central portion 8a1. Further, the groove width of the side portion 8a2 gradually increases from one side in the tread circumferential direction to the vicinity of the center of the central portion 8a1. Further, in the illustrated example, the side portion 8a3 on the circumferential main groove 2b side extends in the tread circumferential direction from the end side on the other side of the central portion 8a1 in the tread circumferential direction to the vicinity of the center of the central portion 8a1. Further, the groove width of the side portion 8a3 gradually increases from the other side in the tread circumferential direction to the vicinity of the center of the central portion 8a1. The side portions 8a2 and the side portions 8a3 are arranged so as to have portions that overlap each other when projected in the tread width direction. The central portion and the side portion will be described in detail later with reference to a cross-sectional view.
The second air chamber portion 8a has a shape in which the length in the tread circumferential direction projected in the tread width direction is longer than the length in the tread width direction projected in the tread circumferential direction, for example, the tread circumferential length. The ratio of the lengths in the tread width direction can be 2 to 4. The groove volume of the second air chamber portion 8a is larger than the groove volume of the second narrowed neck portions 8b and 8c. The specific volume can be appropriately adjusted according to the frequency band of the sound that the second resonator 8 is expected to reduce. The shape of the second air chamber portion 8a is not limited to this shape, and can be various shapes so as to exhibit the function as a resonator.

In the illustrated example, the second narrowed neck portion 8b communicates with one end of the second air chamber portion 8a in the circumferential direction of the tread, and the second narrowed neck portion 8c is the second air chamber portion 8a. It communicates with the other end in the circumferential direction of the tread. On the other hand, the second narrowed neck portion 8b communicates with the other end of the second air chamber portion 8a in the circumferential direction of the tread, and the second narrowed neck portion 8c communicates with the tread of the second air chamber portion 8a. It can also communicate with one end in the circumferential direction. Alternatively, both the second narrowed necks 8b, 8c can communicate with one end of the second air chamber 8a in the tread circumferential direction, and the second narrowed necks 8b, 8c can communicate with each other. Both can also communicate with the other end of the second air chamber 8a in the circumferential direction of the tread. The groove width (opening width) of the narrowed neck portions 8b and 8c is not particularly limited, but is preferably 0.4 to 1.2 mm, for example, and if the groove width is 0.4 mm or more, the second is at the time of touchdown. The function of the second resonator 8 can be exerted by preventing the narrowed neck portions 8b and 8c of the above from closing, and on the other hand, if the groove width is 1.2 mm or less, the second narrowed neck portion 8b can be exerted. , It is possible to secure the rigidity of the land portion around 8c and suppress uneven wear. For the same reason, the groove width of the second narrowed neck portions 8b and 8c is more preferably 0.5 to 0.7 mm. FIG. 2B is a cross-sectional view of the second narrowed neck portion. As shown in FIG. 2B, the second narrowed neck portions 8b and 8c have an enlarged diameter portion on the groove bottom side in which the groove width is larger than the groove width (opening width) at the opening to the tread surface 1. Have. This makes it possible to improve the drainage property when wear progresses. The second narrowed neck portions 8b and 8c may not have an enlarged diameter portion on the groove bottom side. The enlarged diameter portion is preferably provided at a position of 80% to 100% of the groove depth, and preferably has a maximum diameter of 1.5 to 3 times the opening width.

FIG. 3A is an enlarged view showing the second air chamber portion, and FIG. 3B is a cross-sectional view showing the second air chamber portion.
As shown in FIGS. 3A and 3B, the central portion 8a1 has a first bottom-raising portion on the central side in the tread circumferential direction, which is raised from the end side in the tread width direction. In this example, at the center of the groove width of the central portion 8a1, a first bottom-raised portion is provided on the central side in the tread circumferential direction from the end side in the tread circumferential direction (see the bb cross-sectional view). In this example, the bottom is raised smoothly by forming a tapered portion. Therefore, as shown in the bb cross-sectional view, the first bottom-raising portion includes the two tapered portions and the bottom-raised groove bottom constant portion sandwiched between them. On the other hand, the groove wall of the central portion 8a1 gradually decreases in groove depth from the end side to the central portion side of the second air chamber portion 8a (cc cross-sectional view, dd cross-sectional view, See cross-sectional view of e-e).
Next, each of the two side portions 8a2 and 8a3 has a second bottom-raised portion on the central side in the tread circumferential direction, which is raised from the end side in the tread width direction. In this example, the groove depth gradually decreases from the end side to the center side of the second air chamber (see the cross-sectional view taken along the line aa). The height of raising the bottom of the side portions 8a2 and 8a3 with respect to the central portion 8a1 (starting from the bottom portion) is substantially constant in the tread circumferential direction (ff cross-sectional view, gg cross-sectional view, hh). See cross section).
The rigidity of the land portion can be increased by each of the first bottom raising portion and the second bottom raising portion. Further, it is also possible to suppress stone biting at the portion where the first bottom raising portion and the second bottom raising portion are formed.

Further, in the second central land portion 3c, a plurality of fourth width direction sipes 9 extending outward from the circumferential main groove 2b in the tread width direction and ending in the second central land portion 3c, and Multiple fifth widthwise sipes 10 extending inward in the tread width direction from the circumferential main groove 2c on the TE side of the tread end and terminating within the second central land portion 3c are also (spaced in the tread circumferential direction). ) Is formed. As a result, it is possible to increase the edge component in the width direction and improve the kinetic performance such as the traction performance. The fourth and fifth widthwise sipes 9 and 10 do not communicate with the second resonator 8. The sipe width (opening width) of the fourth and fifth widthwise sipes 9 and 10 is not particularly limited, but can be 0.5 to 3 mm, and the fourth and fifth widthwise sipes 9 and 10 can be set. The sipe depth (maximum depth) of the above is not particularly limited, but may be 4 to 8 mm. The second central land portion 3c does not have a circumferential sipe extending in the circumferential direction of the tread. Further, the second central land portion 3c does not have a groove in the width direction.

Next, the land portion 3d has a plurality of widthwise sipes 11 extending in the width direction of the tread. On the other hand, the land portion 3d does not have a circumferential sipe extending in the circumferential direction of the tread. Further, the land portion 3d does not have a groove in the width direction.
In this example, the land portion 3d extends outward in the tread width direction from the sixth width direction sipe 11a and the circumferential main groove 2d communicating from the tread end TE to the circumferential main groove 2d as the width direction sipe 11. It has two types of widthwise sipes 11; a seventh widthwise sipes 11b, which terminates within the land portion 3d (beyond the widthwise center of the land portion 3d in the illustrated example). The sixth width direction sipes 11a and the seventh width direction sipes 11b are alternately arranged in the tread circumferential direction.
The sixth and seventh width direction sipes 11a and 11b are not particularly limited, but extend in the tread width direction (inclination angle 0 °) or incline at an inclination angle of 45 ° or less with respect to the tread width direction. Can be done. Further, in the illustrated example, the sixth and seventh widthwise sipes 11a and 11b do not have a bent portion, but may have a bent portion. The sipe width (opening width) of the sixth and seventh widthwise sipes 11a and 11b is not particularly limited, but can be 0.2 to 3 mm, and the sixth and seventh widthwise sipes 11a and 11b can be set. The sipe depth (maximum depth) of the above is not particularly limited, but may be 3 to 8 mm.

Next, the arrangement relationship between the elements between the land parts 3 will also be described.
First, the plurality of first resonators 6 and the plurality of second resonators 8 have the first air chamber portion 6a and the plurality of second resonators 8 at any position in the tread circumferential direction when viewed in the tread width direction. The second air chamber 6b is arranged so that either or both are present. That is, when a virtual line is drawn in the tread width direction at an arbitrary tread circumferential position, it intersects only with the first air chamber portion 6a, intersects only with the second air chamber portion 8a, or intersects both. It has become. As a result, the rotation of the tire causes a state where there are two air chambers and a state where there are no air chambers in the tread width direction, resulting in a decrease in ride comfort due to a rigidity step, a decrease in exercise performance, uneven wear, and the like. It can be suppressed from being lost. In particular, it is desirable to arrange a sufficient number of resonators in the tread circumferential direction in order to fully exert the muffling effect, but then the circumferential position where two resonators are arranged in the tread width direction is It often occurs. Therefore, with the above configuration, it is possible to suppress deterioration of riding comfort, deterioration of exercise performance, occurrence of uneven wear, etc., while achieving sufficient quietness.

Further, the second widthwise sipes 4b of the land portion 3a and the first narrowed neck portion 6b of the land portion 3b are on extension lines of each other. This makes it possible to efficiently improve the drainage property.
Further, the circumferential sipes are not formed in the land portions 3a to 3d, while the first air chamber portion 6a and the land portion 3c of the first resonator 6 of the land portion 3b are as described above. The second air chamber portion 8a of the second resonator 8 of the above extends along the circumferential direction of the tread. As a result, while ensuring the rigidity of the land portions 3a to 3d, it is possible to secure the edge component in the tread circumferential direction and improve the running performance at the time of cornering.
Further, the land portion 3a to 3d are not arranged with the width direction groove, while the land portion 3a has the width direction sipe 4 and the land portion 3b has the width direction sipe 7. The portion 3c has widthwise sipes 9 and 10, and the land portion 3d has widthwise sipes 11. As a result, while ensuring the rigidity of the land portions 3a to 3d, it is possible to secure the edge component in the tread width direction and improve the traction performance and the like.
Further, in this example, the widthwise sipe 4 of the land portion 3a is curved convexly to one side in the tread circumferential direction, but the widthwise sipe 11 of the land portion 3d is curved convexly to the other side in the tread circumferential direction. ing.

Hereinafter, the action and effect of the pneumatic tire of the present embodiment will be described.
The pneumatic tire of the present embodiment first has a plurality of pin-shaped sipes 5 on the outermost land portion 3a in the width direction on one side in the tread width direction. As a result, as compared with the case where the width direction sipes are provided, the drainage property can be improved by absorbing water from the holes of the pin-shaped sipes 5 while reducing the edge component in the width direction to improve the riding comfort.
Further, in the present embodiment, since the pin-shaped sipes 5 are composed of only one row arranged at intervals in the tread circumferential direction, the reduction in the land area is suppressed as compared with the case where two or more rows are provided. In addition, since a region sandwiched between two rows of pin-shaped sipes is not formed, it is possible to suppress a decrease in the rigidity of the entire land area and prevent a region where the rigidity is locally reduced is formed. can. Further, the pin-shaped sipes 5 do not communicate with the width direction sipes 4, and the pin-shaped sipes 5 are located outside the tire width direction from the midpoint of the outermost land portion 3a in the width direction in the tread width direction. Since they are arranged, it is not necessary to cause a decrease in rigidity due to communication between them or a short distance between them. In addition, since these do not communicate with each other, stone biting can be suppressed. Further, since the pin-shaped sipe 5 is arranged on the extension line of the width sipe 4b, the hole is not arranged in the tread circumferential region between the width sipe 4a and the width sipe 4b. It is possible to secure the rigidity of the land portion in the circumferential direction region. Further, since the outermost land portion 3a in the width direction does not have a circumferential sipe extending in the circumferential direction of the tread, the area of the land portion 3a is secured and the land portion 3a is not divided in the tread width direction. The rigidity of the portion 3a can be increased. As described above, according to the present embodiment, the rigidity of the land portion 3a can be ensured so that the kinetic performance such as steering stability does not deteriorate, and the stone biting can be suppressed.
As described above, according to the pneumatic tire of the present embodiment, while ensuring drainage and riding comfort, other kinetic performance (such as steering stability) is not significantly impaired, and stone biting is performed. It can also be suppressed.

Here, it is preferable that the outermost land portion in the width direction on one side in the tread width direction is the inner land portion when the vehicle is mounted. When mounted on a vehicle, which has a relatively large contribution to ride comfort, drainage is ensured by a pin-shaped sipe on the innermost land in the width direction, compared to the case where drainage is ensured by a width sipe. This is because the deterioration of riding comfort due to the edge component in the width direction can be efficiently suppressed.

Further, it is preferable that the pin-shaped sipes are arranged only on the outermost land portion in the width direction on one side in the tread width direction. Avoiding the decrease in rigidity of the land area due to the formation of pin-shaped sipes in other land areas, ensuring kinetic performance such as steering stability, and stone biting occurs in other land area pin-shaped sipes. This is because it can be avoided. In particular, since the outermost land portion in the width direction when mounted on the vehicle has a relatively large contribution to steering stability, it is efficient to avoid a decrease in rigidity in the land portion. Further, in the land portion other than the outermost land portions in the width direction, for example, a resonator is often arranged as in the present embodiment, and the area of the land portion tends to decrease. Therefore, such a land portion. It is also efficient to avoid a decrease in the rigidity of the.

Further, as in the above embodiment, the first central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on one side in the tread width direction, is formed. A first narrowed neck that communicates a first air chamber terminating in the first central land portion and a circumferential main groove on the outer side of the tire width direction of the first central land portion with the first air chamber portion. A plurality of first resonators having a portion are arranged, the groove width of the first air chamber portion gradually increases from one side in the tread circumferential direction to the other side in a plan view, and the first narrowing neck portion has a portion. , It is preferable that the first air chamber portion communicates with one end of the tread circumferential direction. According to this configuration, the sound generated in the circumferential main groove on the outer side in the tire width direction of the first central land portion can be reduced by the resonator. At that time, the first narrowed neck portion communicates with the end portion of the air chamber portion on the side where the groove width is small, so that the circumferential main groove, the first narrowed neck portion, and the first air chamber portion are formed. It is possible to suppress a decrease in local rigidity due to communication with each other as much as possible.

Further, it is also preferable that the first narrowed neck portion has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width at the opening to the tread. This is because the drainage property at the time of progress of wear can be improved.

Further, the groove width of the circumferential main groove having two or more circumferential main grooves and located on the outermost side in the width direction on the other side in the tread width direction is larger than any of the other circumferential main grooves. Is preferable.

Further, it is preferable that the first air chamber portion extends along the circumferential direction of the tread. This is because the distance in the tread circumferential direction becomes longer when the tire rotates while preventing the edge component in the width direction from increasing, and the deterioration of ride quality can be further suppressed. In particular, when any of the land parts (all land parts in the above embodiment) does not have the circumferential sipe, the peripheral edge component tends to decrease, but according to the above configuration, the first This is because the edge component in the circumferential direction can be secured by the air chamber portion of the above, and the kinetic performance such as steering stability at the time of cornering can be ensured.

Further, in the second central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the outermost land portion in the width direction on the other side in the tread width direction, which is partitioned by the tread end and the circumferential main groove. A plurality of second resonators having a second air chamber portion terminating in the second central land portion and a second narrowed neck portion communicating the circumferential main groove and the second air chamber portion are arranged. The second air chamber has a central portion on the central side in the tread width direction and two raised side portions adjacent to the groove walls on both sides in the tread width direction, and the central portion is the circumference of the tread. It has a first raised portion on the center side in the direction that is raised above the end side in the tread width direction, and each of the two side portions is raised on the center side in the circumferential direction of the tread and raised above the end side in the tread width direction. It is preferable to have a bottom-raised portion of 2. Each of the first bottom-raising portion and the second bottom-raising portion can increase the rigidity of the land portion, and also suppresses stone biting at the place where the first bottom-raising portion and the second bottom-raising portion are formed. Because it can also be done.

It is also preferable that the second narrowed neck portion has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width at the opening to the tread. This is because the drainage property at the time of progress of wear can be improved.

Further, it is preferable that the outermost land portion in the width direction on the other side in the width direction of the tread, which is partitioned by the tread end and the main groove in the circumferential direction, does not have a circumferential sipe extending in the circumferential direction of the tread. This is because it is possible to avoid a decrease in the rigidity of the land portion due to the formation of the circumferential sipe.

Further, a second central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the outermost land portion in the width direction on the other side in the tread width direction, which is partitioned by the tread end and the circumferential main groove, is formed. It is preferable not to have a circumferential sipe extending in the circumferential direction of the tread. This is because it is possible to avoid a decrease in the rigidity of the land portion due to the formation of the circumferential sipe.

Further, as in the above embodiment, the first central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on one side in the tread width direction, is formed. A first narrowing neck that communicates a first air chamber terminating in the first central land portion and a circumferential main groove outside the tire width direction of the first central land portion with the first air chamber portion. A plurality of first resonators having a portion are arranged, and a plurality of first resonators are arranged.
It is partitioned between two main grooves in the circumferential direction and ends in the second central land portion adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on the other side in the tread width direction. A second resonator having a second narrowed neck portion communicating the second air chamber portion and the circumferential main groove on the outer side of the tire width of the second central land portion with the second air chamber portion. Multiple treads are placed
The plurality of first resonators and the plurality of second resonators are the first air chamber portion and the second air chamber when viewed in the tread width direction at any position in the tread circumferential direction. It is preferable that the parts are arranged so that either or both of them are present.
As described above, the rotation of the tire causes a state where there are two air chambers and a state where there are no air chambers in the tread width direction, resulting in a decrease in riding comfort due to a rigidity step, a decrease in exercise performance, uneven wear, etc. (According to the above configuration, there are two or one air chambers in the tread width direction). In particular, it is desirable to arrange a sufficient number of resonators in the tread circumferential direction in order to fully exert the muffling effect, but then the circumferential position where two resonators are arranged in the tread width direction is It often occurs. Therefore, with the above configuration, it is possible to suppress deterioration of riding comfort, deterioration of exercise performance, occurrence of uneven wear, etc., while achieving sufficient quietness.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. In particular, in the present invention, the land portion other than the outermost land portion in the width direction on one side in the tread width direction is not particularly limited and may have various configurations. For example, in the present embodiment, the resonators are arranged in both the first central land portion and the second central land portion partitioned by the two circumferential main grooves, but the two circumferential main grooves are arranged. It is not necessary that any of the land areas partitioned by the above has a resonator. Further, for example, a width direction groove communicating with the tread end may be provided in the outermost land portion in the width direction on the other side in the tread width direction. Further, the outermost land portion in the width direction on one side in the tread width direction also has a width direction sipe 4a communicating from the tread end TE to the circumferential main groove 2a in the above example, but the width direction sipe 4a Can be terminated within the land portion 3a, or the width direction sipes 4a may not be provided. In addition, various modifications and changes are possible.
Further, the pneumatic tire of the present invention is suitable as a pneumatic tire for a passenger car, and is particularly suitable as a pneumatic tire for a minivan.

1: Tread, 2, 2a, 2b, 2c: Circumferential main groove,
3, 3a, 3b, 3c, 3d: Land,
4, 4a, 4b: width direction sipes, 5: pin-shaped sipes,
6: 1st resonator, 6a: 1st air chamber, 6b: 1st stenotic neck,
7: Width direction sipes,
8: 2nd resonator, 8a: 2nd air chamber, 8b: 2nd stenotic neck,
9: Width sipe, 10: Width sipe, 11: Width sipe,
CL: Tire equatorial plane, TE: Tread end

Claims (12)

The tread of the tread has one or more circumferential main grooves extending in the circumferential direction of the tread.
A plurality of widthwise sipes extending in the width direction of the tread and a plurality of pin-shaped sipes are provided in the outermost land portion in the width direction on one side in the width direction of the tread, which is partitioned by the tread end and the main groove in the circumferential direction. death,
The pin-shaped sipe is arranged on an extension of the width sipe without communicating with the width sipe.
The pin-shaped sipes consist of only one row spaced apart in the tread circumferential direction.
The pin-shaped sipes are arranged outside the tire width direction from the midpoint in the tread width direction of the outermost land portion in the width direction.
A pneumatic tire, characterized in that the outermost land portion in the width direction does not have a circumferential sipe extending in the circumferential direction of the tread. The pneumatic tire according to claim 1, wherein the outermost land portion in the width direction on one side in the tread width direction is an inner land portion when mounted on a vehicle. The pneumatic tire according to claim 1 or 2, wherein the pin-shaped sipes are arranged only on the outermost land portion in the width direction on one side in the tread width direction. It has two or more of the circumferential main grooves,
In the first central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on one side in the tread width direction, the inside of the first central land portion. A first having a first narrowed neck portion that communicates the first air chamber portion terminated with a tire and the circumferential main groove on the outer side of the first central land portion in the tire width direction with the first air chamber portion. Multiple resonators are arranged,
In the plan view, the groove width of the first air chamber gradually increases from one side in the tread circumferential direction to the other side.
The pneumatic tire according to any one of claims 1 to 3, wherein the first narrowed neck portion communicates with an end portion of the first air chamber portion on one side in the tread circumferential direction. The pneumatic tire according to claim 4, wherein the first narrowed neck portion has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width at the opening to the tread. It has two or more of the circumferential main grooves,
According to any one of claims 1 to 5, the groove width of the circumferential main groove located on the other side in the tread width direction is larger than any of the other circumferential main grooves. The described pneumatic tire. The pneumatic tire according to any one of claims 4 to 6, wherein the first air chamber portion extends along the circumferential direction of the tread. It has two or more of the circumferential main grooves,
In the second central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the outermost land portion in the width direction on the other side in the tread width direction, which is partitioned by the tread end and the circumferential main groove. A plurality of second resonators having a second air chamber terminated in the second central land portion and a second narrowed neck portion communicating the circumferential main groove with the second air chamber. Placed,
The second air chamber portion has a central portion on the central side in the tread width direction and two raised side portions adjacent to the groove walls on both sides in the tread width direction.
The central portion has a first bottom-raised portion on the central side in the circumferential direction of the tread, which is raised from the end side in the tread width direction.
The pneumatic tire according to claim 7, wherein each of the two side portions has a second bottom-raised portion on the central side in the circumferential direction of the tread, which is raised from the end side in the tread width direction. The pneumatic tire according to claim 8, wherein the second narrowed neck portion has a diameter-expanded portion on the groove bottom side in which the groove width is larger than the groove width at the opening to the tread. It has two or more of the circumferential main grooves,
According to any one of claims 1 to 9, the outermost land portion in the width direction on the other side in the width direction of the tread, which is partitioned by the tread end and the main groove in the circumferential direction, does not have a circumferential sipe extending in the circumferential direction of the tread. Tread tires listed. It has two or more of the circumferential main grooves,
The second central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the outermost land portion in the width direction on the other side in the tread width direction, which is partitioned by the tread end and the circumferential main groove, The pneumatic tire according to any one of claims 1 to 10, which does not have a circumferential sipe extending in the circumferential direction of the tread. It has three or more of the circumferential main grooves,
In the first central land portion, which is partitioned between the two circumferential main grooves and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on one side in the tread width direction, the inside of the first central land portion. A first having a first narrowed neck portion that communicates the first air chamber portion terminated with a tire and the circumferential main groove on the outer side of the first central land portion in the tire width direction with the first air chamber portion. Multiple resonators are arranged,
In the second central land portion, which is partitioned between the two main grooves in the circumferential direction and is adjacent to the inner side in the tread width direction of the outermost land portion in the width direction on the other side in the tread width direction, the inside of the second central land portion. A second having a second narrowed neck portion that communicates the second air chamber portion terminated with a tire and the circumferential main groove on the outer side of the second central land portion in the tire width direction with the second air chamber portion. Multiple resonators are arranged,
The plurality of the first resonators and the plurality of the second resonators are the first air chamber portion and the first resonator when viewed in the tread width direction at any position in the tread circumferential direction. The pneumatic tire according to any one of claims 1 to 11, which is arranged so that either or both of the two air chambers are present.

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