US-12623494-B2 - Pneumatic tire

US12623494B2US 12623494 B2US12623494 B2US 12623494B2US-12623494-B2

Abstract

A pneumatic tire includes circumferential main and narrow grooves, shoulder and second land portions, and closed lug grooves. The circumferential main groove is in a region outer side in a width direction demarcated by an equatorial plane. The circumferential narrow groove is outward of the circumferential main groove in a width direction. The shoulder and second land portions are defined by the circumferential main and narrow grooves. The closed lug grooves extend in the width direction and penetrate the circumferential narrow groove. The closed lug grooves have inner terminating end portions in the width direction inside the second land portion and have outer terminating end portions inside the shoulder land portion. An extension length L 1 _min in the width direction of the shortest first closed lug grooves and an extension length L 1 _max in the width direction of the longest second closed lug grooves have a relationship 1.10≤L 1 _max/L 1 _min≤3.00.

Inventors

Haruna Mizushima

Assignees

THE YOKOHAMA RUBBER CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20181225
Priority Date: 20180130

Claims (20)

1 . A pneumatic tire, comprising: a circumferential main groove disposed in one region demarcated by a tire equatorial plane; a circumferential narrow groove disposed outward of the circumferential main groove in a tire width direction and having a groove width narrower than a groove width of the circumferential main groove, the groove width being a maximum distance between left and right groove walls at a groove opening portion and being measured when the tire is mounted on a specified rim, inflated to specified internal pressure, and in an unloaded state; a shoulder land portion and a second land portion defined by the circumferential main groove and the circumferential narrow groove; a plurality of closed lug grooves extending in the tire width direction and penetrating the circumferential narrow groove, the plurality of closed lug grooves having inner terminating end portions in the tire width direction inside the second land portion, the plurality of closed lug grooves having outer terminating end portions inside the shoulder land portion, the plurality of closed lug grooves being lateral grooves extending in the tire width direction and configured to open when the tire comes into contact with a ground to function as grooves; and an extension length L 1 _min in the tire width direction of a shortest first closed lug groove and an extension length L 1 _max in the tire width direction of a longest second closed lug groove having a relationship 1.10≤L 1 _max/L 1 _min≤3.00; wherein a minimum value Di_min and a maximum value Di_max of a distance Di from the circumferential narrow groove to the inner terminating end portions of the closed lug grooves have a relationship 1.10≤Di_max/Di_min≤3.00, and a minimum value Do_min and a maximum value Do_max of a distance Do from the circumferential narrow groove to the outer terminating end portions of the closed lug grooves have a relationship 0.90≤Do_max/Do_min≤1.10.
2 . The pneumatic tire according to claim 1 , wherein an offset amount ΔDi in the tire width direction of the inner terminating end portions of the closed lug grooves has a relationship 0.10≤ΔDi/W 1 ≤0.60 to a ground contact width W 1 of the second land portion.
3 . The pneumatic tire according to claim 1 , wherein a distance Di from the circumferential narrow groove to the inner terminating end portions of the closed lug grooves and a ground contact width W 1 of the second land portion have a relationship 0.10≤Di/W 1 ≤0.80.
4 . The pneumatic tire according to claim 1 , wherein a distance Do from the circumferential narrow groove to the outer terminating end portions of the closed lug grooves and a ground contact width W 2 of the shoulder land portion have a relationship 0.10≤Do/W 2 ≤0.60.
5 . The pneumatic tire according to claim 1 , wherein the closed lug groove have an inclination angle θ with respect to a tire circumferential direction in a range 50 degrees≤θ≤80 degrees.
6 . The pneumatic tire according to claim 1 , wherein a groove width Wg of the closed lug grooves and the groove width Ws of the circumferential narrow groove have a relationship 0.30≤Wg/Ws≤1.30.
7 . The pneumatic tire according to claim 1 , wherein a groove width Wg_min of a narrowest closed lug groove and a groove width Wg_max of a widest closed lug groove have a relationship 0.90≤Wg_max/Wg_min≤1.10.
8 . The pneumatic tire according to claim 1 , wherein a pair of the closed lug grooves having mutually different lengths are arranged in alternation in a tire circumferential direction.
9 . The pneumatic tire according to claim 1 , wherein the shoulder land portion includes shoulder lug grooves, the shoulder lug grooves having terminating end portions inside the shoulder land portion, extending in the tire width direction, and opening to a tire ground contact edge, and the closed lug grooves are on extension lines of groove center lines of the shoulder lug grooves.
10 . The pneumatic tire according to claim 1 , wherein the shoulder land portion includes shoulder lug grooves, the shoulder lug grooves having terminating end portions inside the shoulder land portion, extending in the tire width direction, and opening to a tire ground contact edge, and the closed lug grooves have groove center lines that do not overlap with groove center lines of the shoulder lug grooves in a tire circumferential direction.
11 . The pneumatic tire according to claim 9 , wherein a distance D 2 from the terminating end portion of the shoulder lug groove to the outer terminating end portion of the closed lug groove opposed to the shoulder lug groove in the tire width direction and a ground contact width W 2 of the shoulder land portion have a relationship 0.10≤D 2 /W 2 ≤0.60.
12 . The pneumatic tire according to claim 9 , wherein an arrangement interval P 1 of the closed lug grooves and an arrangement interval P 2 of the shoulder lug grooves in a tire circumferential direction have a relationship 0.30≤P 1 /P 2 ≤0.70.
13 . The pneumatic tire according to claim 1 , comprising a mounting direction indicator portion specifying that the pneumatic tire is to be mounted on a vehicle with the one region set to an outer side in a vehicle width direction.
14 . The pneumatic tire according to claim 10 , wherein a distance D 2 from the terminating end portion of the shoulder lug groove to the outer terminating end portion of the closed lug groove opposed to the shoulder lug groove in the tire width direction and a ground contact width W 2 of the shoulder land portion have a relationship 0.10≤D 2 /W 2 ≤0.60.
15 . The pneumatic tire according to claim 10 , wherein an arrangement interval P 1 of the closed lug grooves and an arrangement interval P 2 of the shoulder lug grooves in a tire circumferential direction have a relationship 0.30≤P 1 /P 2 ≤0.70.
16 . The pneumatic tire according to claim 1 , wherein the circumferential narrow groove has a groove width of from 3 mm to 7 mm.
17 . A pneumatic tire, comprising: a circumferential main groove disposed in one region demarcated by a tire equatorial plane; a circumferential narrow groove disposed outward of the circumferential main groove in a tire width direction; a shoulder land portion and a second land portion defined by the circumferential main groove and the circumferential narrow groove; a plurality of closed lug grooves extending in the tire width direction and penetrating the circumferential narrow groove, the plurality of closed lug grooves having inner terminating end portions in the tire width direction inside the second land portion, the plurality of closed lug grooves having outer terminating end portions inside the shoulder land portion; and an extension length L 1 _min in the tire width direction of a shortest first closed lug groove and an extension length L 1 _max in the tire width direction of a longest second closed lug groove having a relationship 1.10≤L 1 _max/L 1 _min≤3.00; wherein the shoulder land portion includes shoulder lug grooves, the shoulder lug grooves having terminating end portions inside the shoulder land portion, extending in the tire width direction, and opening to a tire ground contact edge, the closed lug grooves are on extension lines of groove center lines of the shoulder lug grooves, and an arrangement interval P 1 of the closed lug grooves and an arrangement interval P 2 of the shoulder lug grooves in a tire circumferential direction have a relationship 0.30≤P 1 /P 2 ≤0.70.
18 . A pneumatic tire, comprising: a circumferential main groove disposed in one region demarcated by a tire equatorial plane; a circumferential narrow groove disposed outward of the circumferential main groove in a tire width direction; a shoulder land portion and a second land portion defined by the circumferential main groove and the circumferential narrow groove; a plurality of closed lug grooves extending in the tire width direction and penetrating the circumferential narrow groove, the plurality of closed lug grooves having inner terminating end portions in the tire width direction inside the second land portion, the plurality of closed lug grooves having outer terminating end portions inside the shoulder land portion; and an extension length L 1 _min in the tire width direction of a shortest first closed lug groove and an extension length L 1 _max in the tire width direction of a longest second closed lug groove having a relationship 1.10≤L 1 _max/L 1 _min≤3.00; wherein the shoulder land portion includes shoulder lug grooves, the shoulder lug grooves having terminating end portions inside the shoulder land portion, extending in the tire width direction, and opening to a tire ground contact edge, the closed lug grooves have groove center lines that do not overlap with groove center lines of the shoulder lug grooves in a tire circumferential direction, and an arrangement interval P 1 of the closed lug grooves and an arrangement interval P 2 of the shoulder lug grooves in a tire circumferential direction have a relationship 0.30≤P 1 /P 2 ≤0.70.
19 . A pneumatic tire, comprising: a circumferential main groove disposed in one region demarcated by a tire equatorial plane; a circumferential narrow groove disposed outward of the circumferential main groove in a tire width direction and having a groove width narrower than a groove width of the circumferential main groove, the groove width being a maximum distance between left and right groove walls at a groove opening portion and being measured when the tire is mounted on a specified rim, inflated to specified internal pressure, and in an unloaded state; a shoulder land portion and a second land portion defined by the circumferential main groove and the circumferential narrow groove; a plurality of closed lug grooves extending in the tire width direction and penetrating the circumferential narrow groove, the plurality of closed lug grooves having inner terminating end portions in the tire width direction inside the second land portion, the plurality of closed lug grooves having outer terminating end portions inside the shoulder land portion, the plurality of closed lug grooves being lateral grooves extending in the tire width direction and configured to open when the tire comes into contact with a ground to function as grooves; and an extension length L 1 _min in the tire width direction of a shortest first closed lug groove and an extension length L 1 _max in the tire width direction of a longest second closed lug groove having a relationship 1.10≤L 1 _max/L 1 _min≤3.00; wherein the inner terminating end portions of the closed lug grooves are arranged with positions in the tire width direction aligned in the second land portion, and the outer terminating end portions of the closed lug grooves are arranged offset in the tire width direction in the shoulder land portion.
20 . The pneumatic tire according to claim 19 , wherein an offset amount ΔDi of the inner terminating end portions of the closed lug grooves has a relationship 0≤ΔDi/W 1 ≤0.05 to a ground contact width W 1 of the second land portion.

Description

TECHNICAL FIELD The technology relates to a pneumatic tire and particularly relates to a pneumatic tire that can provide dry performance and wet performance of the tire in a compatible manner. BACKGROUND ART Recently, it has been requested for pneumatic tires to improve sports performance not only in circuit traveling but also in traveling in an urban area and a highway. Therefore, to provide dry performance and wet performance of the tire in a compatible manner, a configuration that includes two circumferential main grooves in a region inner side in a vehicle width direction demarcated by a tire equatorial plane, and a single circumferential main groove and a single circumferential narrow groove in a region outer side in the vehicle width direction has been employed. An example of a conventional pneumatic tire that is configured in this manner is the technology described in Japan Unexamined Patent Publication No. 2016-074386. SUMMARY The technology provides a pneumatic tire that can provide dry performance and wet performance of the tire in a compatible manner. A pneumatic tire according to an embodiment of the technology includes a circumferential main groove, a circumferential narrow groove, a shoulder land portion and a second land portion, and a plurality of closed lug grooves. The circumferential main groove is disposed in one region demarcated by a tire equatorial plane. The circumferential narrow groove is disposed outward of the circumferential main groove in a tire width direction. The shoulder land portion and the second land portion are defined by the circumferential main groove and the circumferential narrow groove. The plurality of closed lug grooves extend in the tire width direction and penetrate the circumferential narrow groove. The plurality of closed lug grooves have inner terminating end portions in the tire width direction inside the second land portion. The plurality of closed lug grooves have outer terminating end portions inside the shoulder land portion. An extension length L1_min in the tire width direction of the shortest first closed lug grooves and an extension length L1_max in the tire width direction of the longest second closed lug grooves have a relationship 1.10≤L1_max/L1_min≤3.00. In the pneumatic tire according to the embodiment of the technology, (1) the closed lug grooves penetrating the circumferential narrow groove improve drainage properties in a vicinity of the circumferential narrow groove to improve wet performance of the tire. At the same time, since the closed lug grooves do not open to the circumferential main groove or a tire ground contact edge, rigidity of the left and right land portions defined by the circumferential narrow groove is ensured. These have an advantage that the wet performance and dry performance of the tire are efficiently provided in a compatible manner. Additionally, (2) since the plurality of types of the closed lug grooves having the mutually different extension lengths are arranged at a predetermined interval in a tire circumferential direction, naturally, the terminating end portions of the closed lug grooves in at least one land portion are arranged in the tire circumferential direction while mutually offsetting in the tire width direction. Therefore, compared to a configuration in which the left and right terminating end portions of the closed lug grooves are arranged with the positions in the tire width direction aligned, the long lug groove portions are disposed on a road contact surface of the one land portion, and wide ground contact regions are formed between the adjacent long lug grooves at the same time. This has an advantage that the wet performance and the dry performance of the tire are efficiently improved. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view in a tire meridian direction illustrating a pneumatic tire according to an embodiment of the technology. FIG. 2 is a plan view illustrating a tread surface of the pneumatic tire illustrated in FIG. 1. FIG. 3 is an enlarged view illustrating a main portion of a region outer side in a vehicle width direction of the pneumatic tire illustrated in FIG. 2. FIG. 4 is an explanatory diagram illustrating closed lug grooves of the pneumatic tire illustrated in FIG. 3. FIG. 5 is an explanatory diagram illustrating a modified example of the closed lug grooves illustrated in FIG. 4. FIG. 6 is an explanatory diagram illustrating a modified example of the closed lug grooves illustrated in FIG. 4. FIG. 7 is an explanatory diagram illustrating a modified example of the closed lug grooves illustrated in FIG. 4. FIG. 8 is an explanatory diagram illustrating a modified example of the closed lug grooves illustrated in FIG. 4. FIG. 9 is an explanatory diagram illustrating a modified example of the closed lug grooves illustrated in FIG. 4. FIG. 10 is a table showing results of performance tests of pneumatic tires according to embodiments of the technology. FIG. 11 is an explanato