JPH10338005A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve noise resistant performance at the time of initial abrasion while maintaining proper stability and controllability, in a pneumatic tire provided with a zigzag rib pattern. SOLUTION: In this pneumatic tire, a zigzag main groove 2, extending in a tire peripheral direction T, is provided on a tread surface, to form a zigzag rib, extending in the tire peripheral direction T, by the main groove 2. In this case, a chamfered surface 4, having a circular arc in a plane view, is provided, so as to be recessed on the rib inner side at 1.0 mm or more in a tire width direction from the edge ridge line of a protruded edge part wall surface 3a, on the wall surface 3a having the zigzag rib; and is formed so as to be in a range of 30-100% the groove depth D of the main groove 2 from the rib surface 3X.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire provided with a zigzag rib pattern for reducing noise without impairing steering stability. For entering tires.

[0002]

2. Description of the Related Art In recent years, even for pneumatic tires, tires with lower noise have been strongly demanded from an environmental point of view. By the way, conventionally, in a pneumatic tire provided with a rib pattern, as shown in FIG. 6, a rib 13 formed on a tread surface 11 has a run-out width F (a convex surface adjacent to the tire circumferential direction T on one surface of the rib 13). The tire pattern is formed in a zigzag shape in which the width (length in the tire width direction between the edge Y of the edge portion 13A and the edge Z of the concave edge portion 13B) is increased, thereby increasing the tread rigidity of the rib pattern during cornering.
High handling stability is ensured.

[0003] However, when the swing width F of the rib 12 is set to be large, the road surface resistance when the tire is in contact with the ground while rotating is increased, so that the vibration noise caused by the vibration of the rib 12 is increased. In particular, at the beginning of wear, since the rigidity on the surface side of the rib 12 is weak, the vibration of the rib 12 is large, which is one of the major causes of noise. That is, as the deflection width of the zigzag-shaped rib is increased in order to enhance the steering stability, the excitation sound in the initial stage of wear is greatly increased, which is disadvantageous to the tire noise. This tendency is remarkable in pneumatic tires used for heavy-duty vehicles such as light trucks or the like, which are subjected to high loads, and measures have been required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire provided with a zigzag-shaped rib pattern to improve noise performance at the beginning of wear while maintaining good steering stability. The object of the present invention is to provide a simple pneumatic tire.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a zigzag main groove extending in the tire circumferential direction is provided on a tread surface, and a zigzag rib extending in the tire circumferential direction is formed by the main groove. In the formed pneumatic tire, an arc-shaped chamfered surface in plan view is provided on the convex edge wall surface of the zigzag rib so as to be depressed inward in the tire width direction by 1.0 mm or more from the edge ridge line. It is characterized in that it is formed so as to be in a range of 30 to 100% of the groove depth of the main groove from the surface.

In this way, the convex edge wall surface of the zigzag rib is formed to have an arc-shaped chamfered surface, and the chamfered surface is 1.0 mm from the edge ridge line of the wall surface in the tire width direction.
Depress not less than mmm and 30 to 1 of main groove depth from rib surface
Since it is in the range of 00%, it is possible to eliminate an edge portion of the protruding edge portion that easily vibrates at the time of contact with the ground and to increase the rigidity of the surface portion of the protruding edge portion. Since the road surface resistance is reduced, rib vibration can be suppressed, and as a result, noise performance at the beginning of wear can be improved. In addition, since the zigzag shape of the rib is not changed, steering stability does not deteriorate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 3 show an example of the pneumatic tire of the present invention. On tread surface 1,
A plurality of main grooves 2 extending zigzag in the tire circumferential direction T are provided, and a plurality of zigzag ribs 3 extending in the tire circumferential direction T are formed by these main grooves 2.

Each of the convex edges 3A on both sides of the zigzag rib 3 is provided with a chamfered surface 4 having an arc shape in plan view on a wall surface 3a facing the main groove 2. The chamfered surface 4 is formed so as to be depressed inward of the rib by 1.0 mm or more in the tire width direction from the edge ridgeline E ', which is an extension of the edge ridgeline E of the wall surface 3a (corresponding to the edge ridgeline E before the chamfered surface 4 is formed). And a length H ≧ 1.0 mm drawn in parallel with the tire width direction from the ridge line to the chamfered surface 4). The depth G of the chamfered surface 4 is 30 to 30 of the groove depth D of the main groove 2 from the rib surface 3X.
It is in the range of 100%.

The stepped portion 5 is formed in the wall portion 3a by forming the chamfered surface 4 so as to be depressed inside the rib within the above-described depth range. The wall surface 3b facing the main groove 2 of each concave edge portion 3B of the zigzag rib 3 is entirely formed as an arc-shaped wall surface in plan view.

As described above, according to the present invention, the zigzag rib 3
By providing the chamfered surface 4 as described above on the wall surface 3a of the convex edge portion 3A, the edge portion of the edge portion 3A which is easily vibrated can be removed, and the rigidity of the rib 3 on the surface side of the edge portion 3A can be increased. . Therefore, the road surface resistance when the tire is in contact with the ground while rotating at the time of initial wear is reduced, so that the vibration of the ribs is suppressed, and the vibration noise can be reduced. Therefore, in the pneumatic tire provided with the zigzag rib pattern, it is possible to reduce noise at the beginning of wear. In addition, since the zigzag shape of the rib 3 is not changed, steering stability is not impaired.

The length H from the edge ridgeline E to the chamfered surface 4
Is smaller than 1.0 mm, the ribs vibrate at the beginning of wear, and the noise performance cannot be improved. As the upper limit value of the length H, the deflection width F of the zigzag rib is taken into consideration in terms of steering stability.
It is good to make it within 90% of. Even if the depth G of the chamfered surface 4 is smaller than 30% of the groove depth D of the main groove 2, the vibration of the ribs cannot be effectively suppressed, so that the effect of improving the noise performance at the beginning of wear is poor. . When the rib 3 wears over 30% of the groove depth D of the main groove 2, the height of the rib 3 decreases, and a higher rib rigidity can be secured than at the beginning of wear, so that the zigzag deflection width is reduced. Excitation noise caused by the vibration of the enlarged rib does not increase, and the main groove 2
Since the groove depth D becomes shallower, the air pumping noise generated due to the groove becomes smaller, so that the overall tire noise is reduced. If the depth G of the chamfered surface 4 exceeds 100% of the groove depth D of the main groove 2, there is a problem that the steering stability is reduced.

In the present invention, it is preferable to form a chamfered surface 6 at the edge e1 where the rib surface 3X and the chamfered surface 4 are in contact with each other, as shown in FIG. It is preferable that the chamfered surface 6 has an arcuate cross section as shown in the figure, but it may be a straight cross section (a flat chamfered surface). Step 5
It is preferable that the edge portion e2 of the upper surface 5a is chamfered as shown in FIG. The chamfered surface 7 is also desirably arc-shaped in cross section as shown in the figure, but may be straight.

The chamfered surface 4 can be provided so as to be in a direction substantially parallel to the wall surface 3a as shown in FIGS. 3 and 4 (a). Preferably, as shown in FIG. As the groove bottom side of the main groove 2 protrudes toward the main groove 2, the inner end thereof is a wall surface 3a.
It is good to form it on the inclined surface which contacts with, and do not provide the step part 5.

In the above embodiment, the wall surface 3b of the concave edge portion 3B of the zigzag rib 3 is formed to be an arc-shaped wall surface in plan view. However, the concave edge portion 3B is formed as a portion of the convex edge portion 3A. Since it is harder to vibrate at the time of grounding because of its higher rigidity, it may be a state having a zigzag corner instead of an arc-shaped wall in plan view as shown by a dotted line in FIG.

The convex edge portion 3 used for the length H
The edge ridge E of A is a convex edge 3A as shown in FIG.
When there are a plurality (two in the figure) of the edge ridge lines E, the outermost edge ridge line E1 is indicated. The present invention can be preferably used particularly for a pneumatic tire having a rib pattern in which the run-out width F of the zigzag ribs 3 is increased to 2 mm or more, but is also suitably used for a tire having a run-out width F of less than that. be able to.

The present invention is particularly applicable to JATMA YEAR B
It can be preferably used for pneumatic tires for heavy loads of light trucks or more specified by OOK (1997).

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a tire having a rib pattern shown in FIG. 1 in which a tire size is made common to 650R16 and 10PR and an arc-shaped chamfered surface is provided on the wall surface of a convex edge portion of a zigzag rib, the depth G of the chamfered surface and Ratio G / D of groove depth D of groove
The tire of the present invention, the comparative tires 1 to 3 having the length H from the edge ridge line to the chamfered surface as shown in Table 1, and a conventional tire having no chamfered surface were produced. The run-out width F of the rib of each test tire was 4 mm.

Each of these test tires was rim size 16 ×
5. Attach it to the rim of 50F, set the air pressure to 550 kPa, and attach it to the 2t truck. Under the measurement conditions shown below,
Table 1 shows an evaluation test of noise performance and steering stability.
Were obtained.

Noise Performance On the test course, the passing sound when traveling straight at 40 km / h was measured, and the result was evaluated by an index value with the conventional tire being 100. The larger the value, the better the noise performance.

Steering stability A feeling test was conducted by a panelist on a test course, and the result was evaluated by an index value with the conventional tire being 100. The larger the value, the better the steering stability.

[0021]

[Table 1] As is clear from Table 1, the tire of the present invention can effectively improve the noise performance while maintaining the same steering stability as the conventional tire.

[0022]

As described above, according to the present invention, in a pneumatic tire having a zigzag rib formed thereon, an arc-shaped chamfered surface is specified on the wall surface of the convex edge portion of the zigzag rib as described above. Because of the provision, the vibration of the rib at the time of contact with the ground can be suppressed while maintaining the steering stability, and the noise performance at the beginning of wear can be improved.

[Brief description of the drawings]

FIG. 1 is a main part plan view showing an example of a tread surface of a pneumatic tire of the present invention.

FIG. 2 is an enlarged perspective view of a main part of a convex edge portion of a rib.

FIG. 3 is an enlarged sectional view taken on line AA of FIG. 1;

FIGS. 4A and 4B are cross-sectional views showing another example corresponding to FIG. 3;

FIG. 5 is an explanatory diagram showing a length H when a plurality of sharp edge ridges are present at a convex edge portion of a rib.

FIG. 6 is a plan view of a principal part of a tread surface showing a zigzag rib pattern of a conventional pneumatic tire.

[Explanation of symbols]

1, 11 tread surface 2 main groove 3, 13 rib 3A, 13A convex edge portion 3B, 13B concave edge portion 3X rib surface 3a, 3b wall surface 4 chamfer surface 5 step portion 6, 7 chamfer surface D groove depth of main groove E, E 'Edge ridge F Runout width G Depth of chamfered surface H Length from edge ridgeline to chamfered surface T Tire circumferential direction

Claims (5)

[Claims] 1. A pneumatic tire in which a zigzag main groove extending in the tire circumferential direction is provided on a tread surface and a zigzag rib extending in the tire circumferential direction is formed by the main groove. An arc-shaped chamfered surface in a plan view is provided on the wall surface of the edge portion so as to be depressed by 1.0 mm or more in the width direction of the tire from the edge ridge to the inside of the rib. % Pneumatic tire. 2. The pneumatic tire according to claim 1, wherein an edge portion where the rib surface and the chamfered surface are in contact with each other is chamfered. 3. The pneumatic tire according to claim 1, wherein an edge portion of a stepped upper surface formed by forming the chamfered surface depressed inside the rib is chamfered. 4. The pneumatic tire according to claim 1, wherein the chamfered surface protrudes toward the main groove toward a groove bottom, and an inner end thereof is an inclined surface contacting the wall surface. 5. A concave edge wall surface of the zigzag rib is formed into a circular wall surface in plan view.
The pneumatic tire according to 3 or 4.