JPH04114802U - Tire tread structure - Google Patents

Abstract

(57) [Summary] [Purpose] When pebbles are caught in an annular side groove, stress is dispersed at the bottom of the groove to reduce the occurrence of cracks caused by the stones. [Structure] External dividing ribs 5 are formed on the outer sides of each of the left and right shoulder ribs 3 of the tread portion 2 via annular side grooves 4, and radial uneven portions 6 are formed at the bottom of the side grooves 4 at intervals in the circumferential direction.
is formed.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is mainly applied to the tread structure of tires that are applied to heavy-duty pneumatic tires. It is related to

0002

[Conventional technology]

For heavy-duty pneumatic radial tires used on trucks, buses, etc. , a rib pattern with multiple main grooves in the circumferential direction of the tire is used on the tread surface. is common. In this type of tire, when uneven wear, so-called shoulder drop wear, occurs on the shoulder ribs. There is a problem. Also, when driving on a rutted road surface, the steering wheel may be taken off when wandering. There is also the problem of occurrence of phenomena.

0003 Therefore, the following In the conventional technology, as shown in FIG. On the side, the external splitter is connected via the annular gutter (stress decoupling group) 4. By forming a groove 5, it is possible to reduce uneven wear and wandering phenomenon. I have to. Note that the wear is in a good state as shown by the dotted line.

0004

[Problem that the idea aims to solve]

The above conventional technology has the effect of suppressing the occurrence of uneven wear and wandering phenomena. However, when driving on a road with many pebbles, the outer dividing rib 5 Because the rigidity of the groove is small, the pebbles 14 get stuck in the side gutter 4, stress concentrates on the groove bottom, and the crack occurs. A rack 15 is generated, which leads to the destruction of the outer dividing rib 5 and reduces the above-mentioned suppressing effect. Sometimes I let it happen.

[0005] The present invention is to form radial irregularities at circumferential intervals on the bottom of the side gutter. This helps to disperse stress at the bottom of the groove and increases the rigidity of the outer dividing ribs to prevent pebbles from getting caught. Provides a tire tread structure that prevents cracks at the bottom of the groove as much as possible even when there is damage. The purpose is to

[0006]

[Means to solve the problem]

The specific means for solving the problem in this invention is to The tire tire has an outer dividing rib 5 formed on the outer side of the rib 3 via an annular side groove 4. In the red structure, the groove bottom of the side groove 4 is provided with radially inward unevenness at circumferential intervals. It forms part 6.

[0007]

[Effect]

An annular side groove 4 is provided on the outer side of each of the left and right shoulder ribs 3 of the tread portion 2. By forming the split ribs 5, occurrence of uneven wear and wandering phenomenon is suppressed. When a pebble gets stuck in the side gutter 4, it tries to enter the groove bottom, but there is a gap in the circumferential direction at the groove bottom. The rigidity of the outer dividing rib 5 is increased by forming uneven portions 6 in the radial direction at intervals. By dispersing the stress at the groove bottom, there is less chance of pebbles getting caught and cracks from the groove bottom are reduced. prevent lock occurrence.

[0008]

【Example】

Embodiments of the present invention will be described below with reference to the drawings. In Figures 1 to 3, 1 is a heavy-duty air pump used in trucks, buses, etc. The tread part 2 has multiple (three in the example) circumferential direction of the tire. A main groove 7 is formed, two central ribs 8 in the width direction of the tire, and left and right shocks on the outside. Rudarib 3 is formed. Inside the tire 1 is a carcass layer 9 and a reinforcing belt 10 etc. are buried appropriately.

[0009] An annular side groove 4 is formed on the outer side of each of the left and right shoulder ribs 3, and the shoulder ribs 3 are provided with an annular groove 4. The rib 3 is divided, and the outside of this side groove 4 is an outer divided rib 5. gutter 4 has a width W of 1 to 3 mm, preferably 2 mm or less, and a depth of 10 to 15 mm, for example, in the main groove 7. It is set within the depth, and the width of the outer dividing rib 5 is sufficiently wider than the side groove 4, so it can be easily flipped. It is set so that it does not get corrupted or corrupted.

[0010] The groove bottom of the side groove 4 is formed in a wavy shape, and thereby radial uneven portions 6 are formed at equal intervals in the circumferential direction with a pitch P of 28 mm, for example. Here, regarding the uneven portion 6 on the groove bottom, assuming that the groove depth to the convex portion is d ₂ and the groove depth to the concave portion is d ₁ , 1/4 < d ₂ /d ₁ < 3/4. . This is because if d ₂ /d ₁ is 3/4 or more, the stress distribution at the groove bottom becomes weak, and if d ₂ /d ₁ is 1/4 or less, there is no point in forming the side groove 4.

[0011] The present invention is not limited to the above embodiments, and may be modified as follows. I can do it. For example, the shape of the uneven portion 6 may be a square shape such as a trapezoid other than an arc, or a concave shape. The pitch P of the convex portion 6 may be set to a value other than 28 mm, or the side groove 4 may be waved in the circumferential direction. , In addition, one more side groove is installed inside the side groove 4 in the tread width direction, as indicated by the symbol 4A in Fig. 3. Alternatively, a sub-groove may be formed in the tread portion 2. Also, the side gutter 4A is The bottom of the groove can be formed on an uneven surface or on a flat surface, and the depth of the groove can be adjusted to 4 It is desirable that it be the same as or less than this.

0012

[Effect of the idea]

The present invention is as described above, and by forming the external dividing ribs through the side grooves, In addition to the basic effect of preventing uneven wear as shown in code 2A, the groove bottom of the side gutter has a diameter Because it is an uneven part in the direction, when a pebble gets caught in the gutter, it will be relieved by stress dispersion. It is possible to prevent cracks from occurring in the outer dividing ribs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional perspective view showing essential parts of the present invention.

FIG. 2 is a side view of the present invention.

FIG. 3 is a sectional view taken along the line XX in FIG. 2;

FIG. 4 is a cross-sectional view of a conventional technique provided with external dividing ribs.

[Explanation of symbols]

1 pneumatic tire 2 Tread section 3 Shoulder rib 4 Gutters 5 Outer split rib 6 Uneven part

Claims (1)

[Scope of utility model registration request] [Claim 1] Left and right shoulder ribs of the tread portion (2)
(3) on the outside part, an external dividing rib is inserted through the annular groove (4).
(5) In the tire tread structure in which the side groove (4) is formed, radial irregularities are formed at the groove bottom of the side groove (4) at intervals in the circumferential direction.
(6) A tire tread structure characterized by forming: