Tire
09809062 · 2017-11-07
Assignee
Inventors
Cpc classification
B60C11/1236
PERFORMING OPERATIONS; TRANSPORTING
B60C11/0309
PERFORMING OPERATIONS; TRANSPORTING
B60C2011/036
PERFORMING OPERATIONS; TRANSPORTING
B60C11/125
PERFORMING OPERATIONS; TRANSPORTING
B60C2011/0388
PERFORMING OPERATIONS; TRANSPORTING
B60C2011/0344
PERFORMING OPERATIONS; TRANSPORTING
B60C2011/0369
PERFORMING OPERATIONS; TRANSPORTING
B60C11/1353
PERFORMING OPERATIONS; TRANSPORTING
International classification
B60C11/04
PERFORMING OPERATIONS; TRANSPORTING
B60C11/12
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A tire includes a circumferential direction main groove on a tread surface, first and second circumferential supplemental grooves located on both sides of the circumferential direction main groove, and first and second central land portions formed between the circumferential direction main groove and the first and second circumferential direction supplemental grooves. The first and second central land portions have plural width direction sipes, respectively, and each of the width direction sipes extends to the circumferential main groove, the circumferential main groove has shallow grooved portions and deep grooved portions. The deep grooved portions are deeper than the shallow grooved portions, and the shallow grooved portions are shallower than the circumferential supplemental grooves.
Claims
1. A tire comprising: a circumferential direction main groove extending in a circumferential direction on a tread surface; a pair of circumferential direction supplemental grooves extending in the circumferential direction, and located on both sides of the circumferential direction main groove in a tread width direction; and a pair of central land portions having a rib shape, and formed between the circumferential direction main groove and the pair of circumferential direction supplemental grooves, wherein each of the central land portions has a plurality of sipes, and each of the sipes extends to the circumferential direction main groove to form an opened portion, the circumferential direction main groove has shallow grooved portions and deep grooved portions a depth of which from the tread surface is larger than a depth of the shallow grooved portions from the tread surface, the depth of the shallow grooved portions from the tread surface is smaller than a depth of the circumferential direction supplemental grooves from the tread surface, a plurality of short sipes that are opened to the circumferential direction main groove are formed on the central land portion located on an inner side when the tire is installed on a vehicle, and a length of the short sipes is smaller than a length of the sipes, and a width of the short sipes is larger than a width of the sipes.
2. The tire according to claim 1, wherein each of the deep grooved portions has a circumferential direction deep groove extending in the circumferential direction, and inclined deep grooves inclined to the circumferential direction, and the inclined deep grooves extend from circumferential-direction ends of the circumferential direction deep groove to the opened portions of the sipes of the central land portions.
3. The tire according to claim 2, wherein, in the deep grooved portions, the inclined deep groove extending from one of the circumferential-direction ends of the circumferential direction deep groove toward the opened portion of the sipe of one of the central land portions and the inclined deep groove extending from another of the circumferential-direction ends of the circumferential direction deep groove toward the opened portion of the sipe of another of the central land portions are aligned alternately in the circumferential direction.
4. The tire according to claim 1, wherein an inclined angle, to a tread width direction, of the sipes of the central land portion located on the inner side when the tire is installed on the vehicle is larger than an inclined angle, to the tread width direction, of the sipes of the central land portion located on an outer side when the tire is installed on the vehicle.
5. The tire according to claim 1, further comprising a pair of shoulder land portions on outer sides of the circumferential direction supplemental grooves in the tread width direction, and each of the shoulder land portions having a plurality of lug grooves that communicates with the circumferential direction supplemental groove, wherein the sipes of the central land portions communicate with the circumferential direction supplemental grooves on extended lines extending from the lug grooves toward the circumferential direction supplemental grooves, and cutout portions are formed at positions where the sipes of the central land portions communicate with the circumferential direction supplemental grooves.
6. The tire according to claim 1, wherein chamfer portions are formed at least along a circumferential-direction edge of the central land portion adjacent to the circumferential direction main groove.
7. The tire according to claim 1, wherein a depth of the circumferential direction supplemental grooves from the tread surface is smaller than a depth of the deep grooved portions from the tread surface.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
DESCRIPTION OF EMBODIMENTS
(5) Next, an embodiment of a tire according to the present invention will be explained with reference to the drawings. Specifically, (1) Overall Configurations, (2) Configurations of Circumferential Direction Main Groove, (3) Configurations of Sipes, (4) Configurations of Central Land Portions, (5) Configurations of Shoulder Land Portions, (6) Comparative Estimation, (7) Behaviors and Advantages, and (8) Other Embodiments will be explained.
(6) Note that, in following descriptions about the drawings, identical or equivalent portions are labelled with identical or equivalent reference numbers. However, the drawings are schematic, and it should be kept in mind that ratios of dimensions and so on may be different from their actual ones. Therefore, specific dimensions and so on should be understood in consideration of following explanations, and it may be probable that they include portions that are different among the drawings in their mutual relations of dimensions and their mutual ratio.
(7) (1) Overall Configurations
(8)
(9) As shown in
(10) A first central land portion 310 having a rib shape is formed between the circumferential direction main groove 100 and the first circumferential direction supplemental groove 210, and a second central land portion 320 having a rib shape is formed between the circumferential direction main groove 100 and the second circumferential direction supplemental groove 220. A first shoulder land portion 410 is formed on an outer side of the first circumferential direction supplemental groove 210 in the tread width direction, and a second shoulder land portion 420 is formed on an outer side of the second circumferential direction supplemental groove 220 in the tread width direction.
(11) Plural width direction sipes 311 are formed on the first central land portion 310, and plural width direction sipes 321 are formed on the second central land portion 320. Each of the width direction sipes 311 and 321 is opened to the circumferential direction main groove 100 to form an opened portion 312, 322. In addition, plural short sipes 140 are formed on the first central land portion 310. Detailed configurations of these sipes will be explained later.
(12) Plural first lug grooves 411 are formed on the first shoulder land portion 410. The first fug groove(s) 411 has an opened portion 412 opened to the first circumferential direction supplemental groove 210, and extends from an outer edge of the first shoulder land portion 410 on a side of the first circumferential direction supplemental groove 210 toward an outer side in the tread width direction. Plural second lug grooves 421 are formed on the second shoulder land portion 420. The second fug groove(s) 421 has an opened portion 422 opened to the second circumferential direction supplemental groove 220, and extends from an outer edge of the second shoulder land portion 420 on a side of the second circumferential direction supplemental groove 220 toward an outer side in the tread width direction.
(13) When installing the tire 1 on a vehicle, it is preferable that it is installed so that the first central land portion 310, the first circumferential direction supplemental groove 210 and the first shoulder land portion 410 are located on an inner side of the vehicle, and the second central land portion 320, the second circumferential direction supplemental groove 220 and the second shoulder land portion 420 are located on an outer side of the vehicle. Hereinafter, explanations will be made on the premise that portions to which an ordinal number “first” is added are located on the inner side of the vehicle and portions to which an ordinal number “second” is added are located on the outer side of the vehicle.
(14) (2) Configurations of Circumferential Direction Main Groove 100
(15) As shown in
(16) In
(17) Since the circumferential direction main groove 100 has the above-explained configurations, each of the deep grooved portions 120 forms an S-shaped or reversed S-shaped depressed portion to the shallow grooved portion 110, as shown in
(18) In addition, the inclined deep groove(s) 122A is terminated at a position identical to a position of the opened portion 312 of the width direction sipe 311 in the circumferential direction. Namely, when the tread surface is viewed from front, each of the inclined deep grooves 122A is contiguous to the width direction sipe 311, and each of the inclined deep grooves 122B is contiguous to the width direction sipe 321, as shown in
(19) As shown in
(20) (3) Configurations of Sipes
(21)
(22) It is preferable that the width direction sipe(s) 311 is formed linearly so as to be inclined with an angle θ.sub.1 (in
(23) A cutout portion 323 is formed at a position where the width direction sipe(s) 321 is opened to the second circumferential direction supplemental groove 220. In addition, a cutout portion 313 can be also formed at a position where the width direction sipe(s) 311 is opened to the first circumferential direction supplemental groove 210.
(24) Each of the short sipes 140 is formed as a so-called closed-type sipe extending from an outer edge of the first central land portion 310 on a side of the circumferential direction main groove 100 and terminated in the first central land portion 310. A length is of the short sipe(s) 140 is smaller (shorter) than a length Ls of the width direction sipe 311, and a width ws of the short sipe(s) 140 is larger (wider) than a width Ws of the width direction sipe 311. Note that a “width” of each sipe is a length in a direction perpendicular to a direction along which each sipe extends, and a “length” thereof is an extended length of the center line in its width direction of each sipe.
(25) The short sipe(s) 140 is formed linearly so as to be inclined with an angle θs to the tread width direction. Note that the angle θs is an angle between the center line of the short sipe(s) 140 in its width direction and the tread width direction. The θs is 0° to 20°, and, preferably θs=θ.sub.1.
(26) (4) Configurations of Central Land Portions
(27) As shown in
(28) In the first central land portion 310, chamfer portions 314 are formed along its outer edge on a side of the circumferential direction main groove 100, and chamfer portions 315 are formed along its outer edge on a side of the first circumferential direction supplemental groove 210. In the second central land portion 320, chamfer portions 324 are formed along its outer edge on a side of the circumferential direction main groove 100, and chamfer portions 325 are formed along its outer edge on a side of the second circumferential direction supplemental groove 220. The cutout portion(s) 313, 323 is formed in a range of the chamfer portion(s) 315, 325.
(29) (5) Configurations of Shoulder Land Portions
(30) It is preferable that, in the first shoulder land portion 410, chamfer portions 413 are formed along its outer edge on a side of the first circumferential direction supplemental groove 210, and, in the second shoulder land portion 420, chamfer portions 423 are formed along its outer edge on a side the second circumferential direction supplemental groove 220. It is preferable that cutout portion(s) is formed at the opened portion(s) 412, 422 in a range of the chamfer portion(s) 413, 423.
(31) It is preferable that a depth D4 of the first and second lug grooves 411, 421 on an outer side in the tread width direction is larger (deeper) than the depth D5 of the width direction sipes 311, 321. It is preferable that a level of a bottom surface of the first lug grooves 411 is raised near the opened portion 412 and a depth of the raised portion is smaller than the depth D4, and a bottom surface of the second lug grooves 421 is raised its level near the opened portion 422 and a depth of the raised portion is smaller than the depth D4.
(32) (6) Comparative Estimation
(33) Next, comparative estimation by using tires according to embodiments and comparative examples will be explained with reference to a
(34) With respect to the drainage performance, running test are done at a test course with 2 mm of water depth by using vehicles to which the tires according to the embodiments and the comparative examples are installed so as to accelerate its speed from low speed to high speed in incremental steps, and speeds at which hydroplaning phenomenon occurs are compared. In the
(35) With respect to the handling-and-stability, running test are done at a test course with 2 mm of water depth by using vehicles to which the tires according to the embodiments and the comparative examples are installed, and sensory estimations by a professional driver with respect to grip feeling and steering responsibility are compared. In the
(36) With respect to the ride comfort, running test are done at a test course with 2 mm of water depth by using vehicles to which the tires according to the embodiments and the comparative examples are installed, and sensory estimations by a professional driver with respect to ride comfort are compared. In the
(37) As a result, the tires according to the embodiments 1 and 2 record better results than those by the comparative examples 1 and 2. The comparative example 2 with a larger-depth circumferential direction main groove is superior to the embodiments 1 and 2 with respect to the drainage performance, but the estimation for the comparative example 2 is the lowest with respect to the handling-and-stability. According to the sensory estimations by the professional driver, the embodiments 1 and 2 brings better grip feelings than the comparative examples 1 and 2, and their responsibilities when steering a steering wheel are also better. In addition, the tires according to the embodiment 2 get the best estimation with respect to the ride comfort.
(38) Namely, the tires according to the embodiments 1 and 2 bring better handling-and-stability, and is not inferior to others with respect to the drainage performance. Therefore, it is confirmed that the tires according to the embodiments can satisfy both of the drainage performance and the handling-and-stability on a wet road surface.
(39) (7) Behaviors and Advantages
(40) In the above-explained embodiment, each of the first and second central land portions 310, 320 can secure a drainage performance by having the plural width direction sipes 311, 321. In addition, by the width direction sipes 311, 321, movements of the first and second central land portions 310, 320 during rotations of tires can be restricted, and thereby degradation of rolling resistance can be restricted.
(41) In addition, since the circumferential direction main groove 100 can increase its cross-sectional area by having a so-called “groove in groove”, a drainage performance can be secured while restricting increase of a groove negative rate.
(42) In addition, the first and second central land portions 310, 320 are apparently divided by the circumferential direction main groove 100, but are made contiguous via the sallow grooved portion(s) 110 shallower than the first and second circumferential direction supplemental grooves 210, 220. As a result, movements of the first and second central land portions 310, 320 during rotations of tires can be restricted, and thereby handling-and-stability can be secured.
(43) In addition, when the tread surface is viewed from front, each of the inclined deep grooves 122A is contiguous to the width direction sipe 311. Namely, the large block(s) B is formed by making the small block(s) b1 of the first central land portion 310 and the small block(s) b2 of the second central land portion(s) 320 contiguous to each other via the S-shaped or reversed S-shaped sallow grooved portion(s) 110, and the large blocks B are made contiguous in the circumferential direction with the deep grooved portion 120 interposed therebetween. As a result, the movements of the first and second central land portions 310, 320 during rotations of tires can be further restricted, and thereby handling-and-stability can be secured.
(44) In addition, the inclined deep groove(s) 122A extending from one end of the circumferential direction deep groove(s) 121 in the circumferential direction toward the opened portion(s) 312 of the width direction sipe(s) 311 of the first central land portion 310 and the inclined deep groove(s) 122B extending from another end of the circumferential direction deep groove(s) 121 in the circumferential direction toward the opened portion(s) 322 of the width direction sipe(s) 321 of the second central land portion(s) 320 are aligned alternately along the circumferential direction. Therefore, when running on a wet road surface, drained waters from the first and second central land portions 310, 320 flow into the circumferential direction deep grooves 121 almost equally. As a result, drainage can be done equally on both of an inner side and an outer side of a tire.
(45) In addition, the width direction sipe(s) 311, 321 communicates with the first and second circumferential direction supplemental groove(s) 210, 220 on an extended line(s) extending from the first and second lug groove(s) 411, 421 toward the first and second circumferential direction supplemental groove(s) 210, 220, and the cutout portion(s) 312, 323 is formed at the position(s). Therefore, when running on a wet road surface, drained waters from both of the first and second shoulder land portions 410, 420 flow into the first and second circumferential direction supplemental grooves 210, 220, and then are easily introduced to the circumferential direction main groove 100 via the width direction sipes 311, 321. As a result, a drainage performance can be enhanced.
(46) In addition, the chamfer portions 314, 324 are formed at least along a circumferential-direction edge of the first and second central land portion(s) 310, 320 adjacent to the circumferential direction main groove 100. Therefore, drained waters from the first and second central land portions 310, 320 are easily introduced to the circumferential direction main groove 100 via the width direction sipes 311, 321. As a result, a drainage performance can be enhanced.
(47) In addition, the depth D3 of the first and second circumferential direction supplemental grooves 210, 220 is smaller than the depth D2 of the deep grooved portions 120. Therefore, rigidity can be secured, and handling-and-stability can be secured.
(48) In addition, the width direction sipe(s) 311, 321 is inclined by 0° to 20° to the tread width direction, and extends almost along the tread width direction. Therefore, its edge pressure increases, and thereby a drainage performance can be enhanced by its wiper effect.
(49) In addition, in a case where the angles θ.sub.1, θ.sub.2 between the width direction sipes 311,321 and the tread width direction satisfy θ.sub.1>θ.sub.2, the large block(s) B becomes a block having a shape extending long in the circumferential direction. Although a block loss on an inner side of a tire may become large when a camber is applied to the tire, movements can be restricted by giving the shape extending long in the circumferential direction to the large block(s) B.
(50) In addition, the length is of the short sipes 140 is shorter than the length Ls of the width direction sipes 311, and the width ws thereof is larger than the width Ws of the width direction sipes 311. When tread rubber is compressed due to rotations of the tire 1, movements of the rubber are not absorbed at the width direction sipes 311, and thereby compression rigidity increases and a ride comfort is degraded. Therefore, by providing the short sipes 140, the movements of the rubber are absorbed, and thereby the degradation of a ride comfort can be prevented by restricting the compression rigidity.
(51) In addition, the level the bottom surface of the first and second lug groove(s) 411, 421 is raised near the opened portion(s) 412, 422. Therefore, rigidity is made higher while restricting a speed at which hydroplaning phenomenon occurs under a condition where a steered angle is given (a handle is steered) by communicating the first and second lug groove(s) 411, 421 with the first and second circumferential direction supplemental groove(s) 210, 220, and thereby handling-and-stability can be secured.
(52) In addition, an erroneous installation of a tire by a user can be prevented by forming a tread pattern of which an inner side has a different pattern from an outer side thereof as explained above.
(53) (8) Other Configurations
(54) So far, the present invention is disclosed through the above embodiments. However, it should not be interpreted that the statements and drawings constituting a part of the present disclosure limit the present invention. From this disclosure, a variety of alternate embodiments, examples, and applicable techniques will become apparent to one skilled in the art.
(55) For example, the embodiments of the present invention can be modified as below. Specifically, a tire according to the present invention is explained as a pneumatic tire filled with air or inert gas such as nitrogen gas, but, not limited to this, may be a solid tire that is not filled with air, nitrogen gas and so on.
(56) In addition, it is explained that the circumferential direction main groove 100 extends linearly on the tire equator CL, but, not limited to this, it may be formed at a position set off from the tire equator CL, for example, or may be formed curvedly.
(57) In addition, it is explained that the deep grooved portion(s) 120 extends linearly on the tire equator CL, but, not limited to this, it may be formed at a position set off from the tire equator CL, for example, or may be formed curvedly.
(58) In addition, the width direction sipe(s) 311 is a so-called open-type sipe extending from the circumferential direction main groove 100 to the first circumferential direction supplemental groove 210, but, not limited to this, may be formed as a closed-type sipe terminated in the first central land portion 310 without extending to the first circumferential direction supplemental groove 210, for example. Much the same is true on the width direction sipe(s) 321.
(59) In addition, the short sipe(s) 140 is provided on each of the small block b1 of the first central land portion 310 in
(60) In addition, it is explained that the chamfer portions 314, 315, 324, 325, 413, 423 are formed along the outer edges of the first and second central land portion s 310, 320 and the first and second shoulder land portions 410, 420, but, not limited to this, the chamfer portions may be formed only along the outer edges of the circumferential direction main groove 100, for example.
(61) As described above, needless to say, the present invention includes various embodiments and the like not described here. Therefore, the technical range of the present invention is to be defined only by the inventive specific matter according to the adequate claims from the above description.
(62) Note that, the entire contents of Japanese Patent Application No. 2012-137853 (filed on Jun. 19, 2012) and Japanese Patent Application No. 2012-137857 (filed on Jun. 19, 2012) are incorporated in the specification of the present application by reference.
INDUSTRIAL APPLICABILITY
(63) As explained above, the present invention can be utilizes in a tire that satisfies both of a drainage performance and handling-and-stability on a wet road surface.