CA3073189A1

CA3073189A1 - Pneumatic tire

Info

Publication number: CA3073189A1
Application number: CA3073189A
Authority: CA
Inventors: Toshikazu Yasunaga; Jiro Taniguchi
Original assignee: Toyo Tire Corp
Current assignee: Toyo Tire Corp
Priority date: 2017-08-31
Filing date: 2018-08-16
Publication date: 2019-03-07
Anticipated expiration: 2038-08-16
Also published as: CN111094017B; JP2019043310A; CA3073189C; JP6912973B2; WO2019044514A1; RU2748524C1; CN111094017A

Abstract

This pneumatic tire is provided with: a plurality of shoulder blocks 6 which are provided in side sections 2, are defined by communication grooves 8 extending in a tire circumferential direction and by lateral grooves 7 extending in a tire width direction, and are arranged next to each other in the tire circumferential direction; auxiliary ribs 10 provided on the side sections 2 and extending in the tire circumferential direction along the shoulder blocks 6; and protrusions 11 provided on the side sections 2 and extending from the auxiliary ribs 10 into the lateral grooves 7. As a result of this configuration, the pneumatic tire has good resistance to external damage, good cooling performance, and good traction performance, the rigidity of the auxiliary ribs can be increased, the lateral grooves exhibit good snow discharge performance, and a sufficient amount of longitudinal deflection of the side section is ensured.

Description

DESCRIPTION
PNEUMATIC TIRE
TECHNICAL FIELD
[0001] The present invention relates to a pneumatic tire.
BACKGROUND ART

[0002] A conventionally publicly known pneumatic tire includes turbulent-flow generating projections that are provided on the surface of the tire at intervals in the tire circumferential direction and extend from the inner circumference side toward the outer circumference side (see Patent Document 1).

[0003] Such a conventional pneumatic tire merely includes the turbulent-flow generating projections on side portions of the pneumatic tire, which provides cooling performance, however, it is uncertain whether the amount of vertical deformation of the tire can be reduced or not. Further, the projections are configured to generate a turbulent-flow, and thus, it is clear that the projections are not configured to avoid remaining snow in the grooves which is a problem for snow tires.
PRIOR ART DOCUMENT
PATENT DOCUMENT

[0004] Patent Document 1: JP 5374362 B
SUMMARY OT THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] An object of the present invention is to provide a pneumatic tire which achieves increased rigidity of the reinforcing rib to exhibit traction performance, enhanced anti-damage performance and cooling performance, smooth drainage of the snow from the lateral groove, and reduced amount of vertical deformation of side portion.
MEANS FOR SOLVING THE PROBLEMS

[0006] One aspect of the present invention comprises:
a plurality of shoulder blocks provided on a side portion and arranged in a tire circumferential direction, each of the plurality of shoulder blocks being defined by a communication groove extending in a tire circumferential direction and lateral grooves extending in a tire width direction;
an auxiliary rib provided on the side portion and extending in the tire circumferential direction and; and a projection provided on the side portion and extending from the auxiliary rib so as to protrude into the lateral groove.

[0007] With this configuration, the projection protects the side portion and increases the rigidity of the reinforcing rib, thereby enhancing the traction performance of the tire. The projection causes the air passing over the surface of the tire to form a turbulent flow to exhibit the cooling performance. In addition, the projection causes proper drainage of the snow that has entered the lateral grooves.

[0008] The projection preferably includes first projections and second projections differing in a protruding size into the lateral groove, and alternately arranged in the tire circumferential direction.

[0009] Preferably a width size of the projection is gradually narrowed toward a tip end of the projection.

[0010] The projection preferably includes a slanted surface becoming closer to a bottom surface of the lateral groove toward a tip end of the projection.
EFFECT OF THE INVENTION

[0011] According to the present invention, the projection extending from the reinforcing rib into the lateral groove is provided. This increases the rigidity of the reinforcing rib to exhibit traction performance, enhances anti-damage performance and cooling performance, and also enables smooth drainage of the snow from the lateral groove.
BRIEF DESCRIPTION OF THE DRAWINGS

[0012]
Fig. 1 is a perspective view showing part of a pneumatic tire according to the present embodiment;
Fig. 2 is a partial development view of the pneumatic tire shown in Fig. 1;
Fig. 3A is a partial enlarged view of Fig. 2;
Fig. 3B is a longitudinal sectional view of a first projection shown in Fig. 3A; and Fig. 3C is a longitudinal sectional view of a second projection shown in Fig. 3A.

DESCRIPTION OF EMBODIMENTS

[0013] An embodiment according to the present invention will be described below with reference to the accompanying drawings. In addition, the following descriptions are essentially mere illustrations, and are not intended to limit the present invention, its application, or its use.
Further, the figures are schematic views, and the ratio of each dimension etc. in the figures is different from the actual one.

[0014] Fig. 1 is a perspective view showing part of a pneumatic tire according to the present embodiment. Although not shown, the pneumatic tire has a configuration in which a carcass is stretched between a pair of bead cores, a belt is wound around an outer peripheral side of an intermediate portion of the carcass for reinforcement, and a tread portion 1 is disposed on an outer diameter side of the tire. Fig. 1 omits sipes 9 formed on land portions 3 of the tread portion 1.

[0015] Fig. 2 is a partial development view showing a tread pattern of the pneumatic tire shown in Fig. 1. The tread pattern includes the tread portion 1 to come in contact with a road surface and side portions 2 on both sides of the tread portion 1. The land portions 3 constituting the tread pattern are connected to each other at a center in a tire width direction (indicated by arrow W in Fig. 2) that is stretched in a tire circumferential direction (indicated by arrow R in Fig. 2), and the land portions 3 are arranged at predetermined intervals in the tire circumferential direction and extend toward both ends in the tire width direction.

[0016] The land portions 3 include a center rib 4 that is stretched in the tire circumferential direction at the center in the tire width direction.
Further, the land portions 3 include center block parts 5 and shoulder blocks 6 both extending in the tire width direction.

[0017] The center block parts 5 and the shoulder blocks 6 are arranged at predetermined intervals in the tire circumferential direction, and are defined by lateral grooves 7 and communication grooves 8, each of the communication grooves 8 allowing adjacent ones of the lateral grooves 7 in the tire circumferential direction to communicate each other, the lateral grooves 7 extending outwardly in the tire width direction and diagonally in the tire circumferential direction.

[0018] The lateral grooves 7 include first lateral grooves 7a and second lateral grooves 7b that are wider than the first lateral grooves. The first lateral grooves 7a and the second lateral grooves 7b are alternately arranged in the tire circumferential direction. In addition, the lateral grooves 7 arrayed on one side of a center line 0 (tire center line) disposed at the center in the tire width direction are arranged differently from those arrayed on the other side of the center line 0 in the tire width direction and in the tire circumferential direction.

[0019] The communication grooves 8 include first communication grooves 8a disposed closer to the tire center line and second communication grooves 8b disposed outwardly in the tire width direction.
The first communication grooves 8a and the second communication grooves 8b are alternately formed in the tire circumferential direction.
The first communication grooves 8a separate first center block parts 5a from first shoulder blocks 6a. Further, the second communication grooves 8b separate second center block parts 5b from second shoulder blocks 6b. The second center block parts 5b are longer than the first center block parts 5a, and the second shoulder blocks 6b are shorter than the first shoulder blocks 6a.

[0020] The center rib 4 and the center block parts 5 each include a plurality of sipes 9 arranged at predetermined intervals such that the sipes 9 intersect an extending direction of the center rib 4 and the center block parts 5. Each of the sipes 9 includes straight portions 9a that communicate the lateral grooves 7 on both sides thereof, and a corrugated portion 9b that communicates the straight portions.

[0021] Each of the shoulder blocks 6 includes three rows of sipes 9 arranged along the extending direction of the each of the shoulder blocks 6. One of the straight portions in each of the sipes 9 communicates one of the communication grooves 8, and an end of the other one of the straight portions is located at a boundary between the tread portion 1 and either of the side portions 2.

[0022] Peripheral edges of the tire include auxiliary ribs 10 each of which is annularly extended in the tire circumferential direction. Each of the auxiliary ribs 10 includes projections 11 extending toward corresponding one of the lateral grooves 7. The projections 11 include first projections 1 la respectively extending into the first lateral grooves and second projections 11 b respectively extending into the second lateral grooves.

[0023] As shown in Figs. 3A and 3B, the first projections 1 la have a relatively small protruding size Li projecting into the respective first lateral grooves 7a (a length in a tire outer diameter direction measured from an inner peripheral edge of the auxiliary rib 10). Specifically, the protruding size Li is within a range of 5 mm to 50 mm (20 mm in the present embodiment). The first projections 1 la have a height I-1 (a height measured from the surface of the side portion 2) that is the same as that of the auxiliary ribs 10, and is within a range of 0.5 mm to 10 mm (1.2 mm in the present embodiment). The tips of the first projections 1 la each include a slanted surface 11c becoming gradually closer to a bottom surface of the individual lateral groove 7. An angle a formed by the slanted surface 11c and an upper surface lid of each first projection ha is within a range of 10 to 800 (35 in the present embodiment). The first projections 1 la each are gradually tapered toward the tip thereof, and an angle 01 formed by both side surfaces thereof is within a range of 30 to 30 (14 in the present embodiment). The angle 01 is set larger than an angle 02 formed by both side surfaces of the first lateral groove 7a on the side portions 2. Further, the slanted surface 11c is formed within a length L2 from the tip of each first projection 1 la. The length L2 is within a range of 3 mm to 50 mm (7.5 mm in the present embodiment). Further, the tip of each first projection 1 ha has a width size wl in a range of 1 mm to 20 mm (1.8 mm in the present embodiment), at which corresponding one of the first lateral grooves 7a has a width size w2 in a range of 3 mm to 30 mm (9.9 mm in the present embodiment). Note that a center line Cl of each first projection 11 a practically coincides with a center line C2 of corresponding one of the first lateral grooves 7a.

[0024] As shown in Figs. 3A and 3C, the second projections 11 b have a large protruding size L3 projecting from the auxiliary rib 10 as compared with the first projections, and extend to the vicinity of the boundary between the tread portion 1 and either of the side portions 2.
Specifically, the protruding size L3 is within a range of 10 mm to 70 mm (26 mm in the present embodiment). The height H of the second projections 11 b is the same as that of the first projections 11a. The tips of the second projections 11 b each include a slanted surface 1 le that is similar to those of the first projections 1 la. An angle 13 formed by the slanted surface 1 le and an upper surface 1 lf of each second projection 1 lb is within a range of 10 to 80 (40 in the present embodiment). The second projections 11 b each are gradually tapered toward the tip thereof, and an angle 03 formed by both side surfaces thereof is within a range of 3 to 30 (9 in the present embodiment). The angle 03 is set larger than an angle 04 formed by both side surfaces of the second lateral groove 7b on the side portions 2. Further, the slanted surface 1 le is formed within a length L4 from the tip of each second projection 1 lb. The length L4 is within a range of 5 mm to 60 mm (13 mm in the present embodiment).
Further, the tip of each second projection 1 lb has a width size w3 in a range of 1 mm to 20 mm (2.2 mm in the present embodiment), at which corresponding one of the second lateral grooves 7b has a width size w4 in a range of 3 mm to 30 mm (10.2 mm in the present embodiment). Note that a center line C3 of each second projection llb practically coincides with a center line C4 of corresponding one of the second lateral grooves 7b.

[0025] In this manner, the first projections 11a and the second projections 11b having different protruding sizes are arranged alternately in the tire circumferential direction, which provides an appropriate balance in rigidity to the side portions 2 each including the first shoulder blocks 6a and the second shoulder blocks 6b having different lengths.
Since the shoulder blocks 6a and 6b have different rigidity due to the difference in length, so-called heel and toe wear is likely to occur during traveling. However, occurrence of such heel and toe wear is reduced by allowing the first projections 11a and the second projections 11b to increase the rigidity of the first shoulder blocks 6a and the second shoulder blocks 6b and make the first shoulder blocks 6a and the second shoulder blocks 6b resistant to deform. In particular, winter tires are likely to reduce the rigidity because of a large number of sipes 9 formed also on the shoulder blocks 6. However, such reduction in rigidity is suppressed by the projections 11, and thus a desired cornering performance can be obtained.

[0026] In addition, the projections 11 are gradually tapered toward the tips and include the slanted surfaces 11c at the tips thereof. This configuration enables smooth drainage of the snow even if snow remains in the lateral grooves 7, because deformation of the side portions 2, which occurs when the tread portion 1 contacts the ground, causes the projections 11 to enter the bottom side of the snow in the lateral grooves 7.

[0027] Each of the shoulder blocks 6 includes a protrusion 12 at its outer end in the tire width direction. The protrusion 12 includes a sawtooth-shaped first protrusion 12a and two second protrusions 12b having a parallelogram shape formed along each tooth portion.

[0028] The pneumatic tire including the projections 11 with the above-described configuration provides the following effects.
(1) The projections 11 suppress foreign objects such as curbstones from contacting the side portions 2, and thus excellent anti-damage performance can be exhibited.
(2) The projections 11 turn the wind generated during travelling into a turbulent flow, and thus heat dissipation is enhanced and excellent cooling performance can be exhibited.
(3) The projections 11 reinforce the auxiliary ribs 10 by enhancing their rigidity, and thus excellent traction performance can be exhibited.
(4) The projections 11 are disposed inside the respective lateral grooves 7, and thus snow in the lateral grooves 7 can be drained. In other words, the snow that has entered the lateral grooves 7 moves onto the slanted surfaces of the projections 11 to be drained when the tread portion 1 contacts the ground and causes deformation. Thereby, snow does not remain in the lateral grooves 7, and a good travelling state can be obtained.
(5) The projections 11 increase the rigidity of the shoulder blocks 6, and thus occurrence of heel and toe wear can be reduced and desired cornering performance can be obtained.
REFERENCE SIGNS LIST

[0029] 1: Tread portion, 2: Side portion, 3: Land portion, 4: Center rib, 5: Center block part, 5a: First center block part, 5b: Second center block part, 6: Shoulder block, 6a: First shoulder block, 6b: Second shoulder block, 7: Lateral groove, 7a: First lateral groove, 7b: Second lateral groove, 8: Communication groove, 8a: First communication groove, 8b: Second communication groove, 9: Sipe, 10: Auxiliary rib, 11: Projection, ha:
First projection, 11b: Second projection, 11c: Slanted surface, 12:
Protrusion, 12a: First protrusion, 12b: Second protrusion

Claims

1. A pneumatic tire, comprising:
a plurality of shoulder blocks provided on a side portion and arranged in a tire circumferential direction, each of the plurality of shoulder blocks being defined by a communication groove extending in a tire circumferential direction and lateral grooves extending in a tire width direction;
an auxiliary rib provided on the side portion and extending in the tire circumferential direction and; and a projection provided on the side portion and extending from the auxiliary rib so as to protrude into the lateral groove.

2. The pneumatic tire according to claim 1, wherein the projection includes first projections and second projections differing in a protruding size into the lateral groove, and alternately arranged in the tire circumferential direction.

3. The pneumatic tire according to claim 1 or 2, wherein a width size of the projection is gradually narrowed toward a tip end of the projection.

4. The pneumatic tire according to any one of claims 1 to 3, the projection includes a slanted surface becoming closer to a bottom surface of the lateral groove toward a tip end of the projection.