KR100644872B1 - Studless Type Heavy duty Pneumatic Radial Tire - Google Patents

Abstract

The pneumatic tire for heavy load of the studless load of the present invention is a center longitudinal groove formed in the center portion of the tread and applied in the running direction of the tire, a shoulder longitudinal groove formed on the shoulder portion of the tread, and the center longitudinal groove and the shoulder longitudinal groove Center-shoulder longitudinal grooves formed between are applied; A center block defined by the longitudinal groove and formed at the center portion of the tread, a shoulder block formed at the shoulder portion, and a center-shoulder block formed between the center block and the shoulder block; A transverse groove is applied to the block in the tread width direction of the tire; It is characterized by satisfying the following relational expression.

<Relationship>

9 ° ≤α + β≤16 °, α≥β

Here, α is the inclination angle of the front side of the transverse groove of the center block and the center-shoulder block, and β is the inclination angle of the rear side of the transverse groove of the center block and the center-shoulder block.

Block, Groove, Tilt Angle, Tire Driving Direction Centerline

Description

Studless Type Heavy duty Pneumatic Radial Tire             

1 is a plan view of a pattern of a pneumatic radial tire for studless heavy load according to a conventional embodiment.

Figure 2 is a plan view of a pattern of a pneumatic radial tire for studless heavy load according to an embodiment of the present invention.

3 is a cross-sectional view of the horizontal groove A-B of FIG. 2.

<Description of the symbols for the main parts of the drawings>

C / L: Tire driving direction center line R1: Center block

R2, R3: Center-Shoulder Block R4: Shoulder Block

a, a ': unit center block d, d': unit shoulder block

b, b ', c, c': unit center-shoulder block G1: center longitudinal groove

G2: center-shoulder longitudinal groove G3: shoulder longitudinal groove

G4: Center lateral groove G5, G6: Center-shoulder lateral groove

G7: Shoulder Lateral Groove

S: Transverse sipe of center and shoulder block

α: forward angle of inclination of lateral groove of center block and center-shoulder block

β: inclination angle of the rear side of the horizontal groove of the center block and the center-shoulder block

The present invention relates to a pneumatic radial tire for heavy-duty heavy loads, and more particularly, to improve wear resistance and improve groove wear resistance without deteriorating snow and wet (wet) traction performance, which are the functions of winter. It relates to a pneumatic radial tire for studless heavy loads to prevent cracking.

In general, heavy-loaded radial pneumatic tires for snow with a block pattern are required for long life and strong snow & moisture traction performance, and at the same time, high-speed driving performance according to the optimization of the road and high performance of the vehicle.

Conventionally, a spike pin has been inserted into the tread pattern in order to improve the driving and braking force on a snowy road surface.

This will be described in more detail with reference to FIG. 1.

Referring to Fig. 1, a conventional heavy-load pneumatic radial tire has a plurality of blocks by longitudinal grooves (center longitudinal grooves, shoulder longitudinal grooves) L1 (L2) formed in the circumferential direction (driving direction) of the tire in the tread portion. (Center block, shoulder block) (B1) (B2) is partitioned, and horizontal grooves (center horizontal grooves, shoulder horizontal grooves) L3 and L4 are applied in the width direction of the tire, and to the shoulder block B2. Spike pin 30 was inserted.

However, when the spike pin 30 is inserted into the shoulder block B2 of the tread portion as described above, the road is damaged by the spike pin 30 during driving, and the noise is generated, and the use thereof gradually decreases due to deterioration of the driving performance. It is a trend to limit.

The studless heavy-duty radial tire with the corresponding spike pin 30 removed has been continuously demanded to improve the braking force and driving force on the snow road, and to suppress uneven wear, which is a rate-breaking relationship, and to prevent cracking at the groove groove bottom. It is becoming.

Accordingly, a technique has been devised to increase the height of a block partitioned into lateral grooves and longitudinal grooves and to insert a plurality of sipes in each block in order to meet the needs.

However, as described above, increasing the height of a block and inserting a large number of sipes in each block may result in insufficient rigidity of the block and excessive movement of the block, causing uneven wear such as heel and toe, resulting in grooves or sipes. Cracks have occurred in the interior.

The present invention has been made to solve the above problems, its purpose is to improve the wear resistance and crack generation between the groove bottom without deterioration of snow and wet traction performance which is a natural function for winter It is to provide a pneumatic radial tire for heavy winter loads to prevent winter studs.

In order to achieve the above object, the studless heavy-duty pneumatic tire of the present invention is applied to the running direction of the tire and formed in the center longitudinal groove of the tread, the shoulder longitudinal groove formed in the shoulder portion of the tread and the center bell. A center-shoulder longitudinal groove formed between the groove and the shoulder longitudinal groove is applied;

A center block defined by the longitudinal groove and formed at the center portion of the tread, a shoulder block formed at the shoulder portion, and a center-shoulder block formed between the center block and the shoulder block;

A transverse groove is applied to the block in the tread width direction of the tire; It is characterized by satisfying the following relational expression.

<Relationship>

9 ° ≤α + β≤16 °, α≥β

Here, α is the inclination angle of the front side of the transverse groove of the center block and the center-shoulder block, and β is the inclination angle of the rear side of the transverse groove of the center block and the center-shoulder block.

If α + β <9 °, cracks can be prevented at the bottom of the groove, but it is difficult to prevent heel and toe wear. If α + β> 16 °, the radius of curvature of the groove groove bottom is too small. It is not preferable because stress tends to concentrate at the bottom of the jersey groove and cracks are generated.

In addition, the present invention is characterized in that the β is 3 ° to 7 °.

When the front inclination angle α is larger than the rear inclination angle β, the bending deformation of the rear end portion of the block in the tire driving direction is minimized to suppress slip and heel and toe wear. Wear) can be prevented. In addition, when the front inclination angle α is larger than the rear inclination angle β, groove space can be secured, thereby maximizing Snow and Wet Traction performance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a plan view of a pattern of a pneumatic radial tire for studless heavy load according to an embodiment of the present invention.

2, the tread portion of the studless heavy-duty radial tire of the present invention has a seven-ribbed pattern consisting of a groove and a block partitioned by the groove.

The block is formed in the center of the tread, the center block (R1) which is a block in contact with the tire driving direction center line (C / L) or closest to the tire driving direction center line (C / L); A shoulder block (R4) formed at the shoulder portion of the tread and one or more center-shoulder blocks (R2) (R3) located between the center block and the shoulder block.

The center block R1 is formed by connecting a plurality of unit blocks (hereinafter, referred to as' unit center blocks') a and a 'in the tire driving direction.

The shoulder block R4 is formed by connecting a plurality of unit blocks (hereinafter, referred to as' unit shoulder blocks') d and d 'in the tire driving direction.

The center-shoulder block (R2) (R3) is formed by a plurality of unit blocks (hereinafter referred to as 'unit center-shoulder block') (b, b ') (c, c') are connected in the tire driving direction do.

The groove includes a longitudinal groove applied in the circumferential direction (running direction) of the tire and a lateral groove applied in the tread width direction.

The longitudinal groove is a center longitudinal groove (G1) formed in the center of the tread; A shoulder longitudinal groove G3 formed on the shoulder portion of the tread; And at least one center-shoulder longitudinal groove G2 positioned between the center longitudinal groove and the shoulder longitudinal groove.

The center longitudinal groove G1 is also a groove located between the center block R1 and the center-shoulder block R2.

In addition, the horizontal groove is a center horizontal groove (G4) between the unit center block (a) and the unit center block (a '); A shoulder transverse groove (G7) between the unit shoulder block (d) and the unit shoulder block (d '); And at least one center-shoulder transverse groove G5 (G6) between the unit center-shoulder block (b) (c) and the unit center-shoulder block (b ') (c').

3 is a cross-sectional view of the horizontal groove A-B of FIG. 2.

As shown in Figure 3, the present invention is characterized in that the specifications of the center horizontal groove and the center-shoulder horizontal groove have the following relationship.

<Relationship>

9 ° ≤α + β≤16 °, α≥β

Here, α is the inclination angle of the front side of the transverse groove of the center block and the center-shoulder block, and β is the inclination angle of the rear side of the transverse groove of the center block and the center-shoulder block.

Here, the inclination angle refers to the inclination angle of the groove inner surface with respect to the vertical line perpendicular to the surface of the tread pattern.

The 'front side' indicates a portion 'A' when the tire is driven in a 'tire traveling direction' (indicated by an arrow).

The 'rear side' refers to a portion 'B' when the tire is driven in a 'tire traveling direction' (indicated by an arrow).

When α + β ≥ 9 °, the rigidity of one or both ends of the ground block is increased, so that the bending deformation of the block can be reduced during the driving / driving to suppress heel and toe wear and maintain snow and wet traction performance. .

If α + β <9 °, cracks can be prevented at the bottom of the groove, but it becomes difficult to prevent heel and toe wear.

In addition, if α + β ≦ 16 °, the radius of curvature of the groove groove bottom portion is kept at a constant size so that extreme stress concentration on the groove groove bottom portion can be avoided, so that the occurrence of cracks can be suppressed.

In the above, when α + β> 16 °, the radius of curvature of the groove groove bottom is too small, so that stress is easily concentrated in the groove bottom, causing cracks.

When the front inclination angle α is larger than the rear inclination angle β, the bending deformation of the rear end portion of the block in the tire driving direction is minimized to suppress slip and heel and toe wear. Wear) can be prevented. In addition, when the front inclination angle α is larger than the rear inclination angle β, groove space can be secured, thereby maximizing Snow and Wet Traction performance.

The present invention made as described above can improve the wear resistance and prevent the occurrence of cracks between the bottom of the groove without deterioration of the snow (snow) and wet (wet) traction performance that is the original function for the winter.

Accordingly, the present invention can improve the durability of the tire.

Claims (2)

A center longitudinal groove applied in the running direction of the tire and formed at the center portion of the tread, a shoulder longitudinal groove formed at the shoulder portion of the tread, and a center-shoulder longitudinal groove formed between the center longitudinal groove and the shoulder longitudinal groove; A center block defined by the longitudinal groove and formed at the center portion of the tread, a shoulder block formed at the shoulder portion, and a center-shoulder block formed between the center block and the shoulder block; Transverse grooves are applied to the center block, the center-shoulder block and the shoulder block in the tread width direction of the tire; A pneumatic radial tire for studless heavy loads, which satisfies the following relational expression. <Relationship> 9 ° ≤α + β≤16 °, α≥β Here, α is the inclination angle of the front side of the transverse groove of the center block and the center-shoulder block, and β is the inclination angle of the rear side of the transverse groove of the center block and the center-shoulder block. The pneumatic radial tire according to claim 1, wherein β is 3 ° to 7 °.

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