JP4596706B2 - Pneumatic tire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire, and relates to a pneumatic tire with improved quiet performance, taking off-road performance and snow performance into consideration.
[0002]
[Prior art]
To improve off-road performance and snow performance in pneumatic tires, increase the component of lug grooves (generally called lateral grooves or sub grooves in the radial direction) in the tread pattern, that is, the lug grooves are thick grooves It is configured to earn traction on off-road (sandy ground) and icy and snowy roads.
[0003]
[Problems to be solved by the invention]
If the lug groove is a thick groove, the off-road performance and the snow performance can be improved. However, since the lug groove is a thick groove, there is a problem that uneven wear tends to occur at the contact end and the quietness is impaired.
In particular, in recent years, road maintenance has also progressed, and quietness is required while ensuring off-road performance and snow performance. In addition, uneven wear on dry road surfaces (dry road surfaces) is suppressed to ensure steering stability. There is a demand for ensuring drainage on wet road surfaces (wet road surfaces).
[0004]
The present invention includes a center rib formed in a zigzag shape on the left and right formed on the equator of the tread, a center main groove formed continuously on the left and right of the center rib in the circumferential direction, and a left and right shoulder in the circumferential direction. An object of the present invention is to provide a pneumatic tire that satisfies the above-mentioned demands by providing an organic relationship with respect to the formation positions of the formed left and right shoulder main grooves.
[0005]
[Means for Solving the Problems]
In order to achieve the above-described object, a pneumatic tire according to claim 1 includes a center rib 2 formed in a left and right zigzag shape continuously in the circumferential direction on the equator of the tread 1, and a circumferential direction on the left and right of the center rib 2 Left and right center main grooves 3L and 3R formed in a left and right zigzag shape, left and right shoulder main grooves 4L and 4R continuously formed in the circumferential direction on the left and right shoulders of the tread 1, and the left and right center mains The left and right blocks 6L and 6R formed in the circumferential direction by the left and right sub-grooves 5L and 5R formed by connecting the grooves 3L and 3R and the left and right shoulder main grooves 4L and 4R at intervals in the circumferential direction; Left and right shoulder main grooves 4L, 4R and left and right tread ends are connected to each other and left and right shoulder sub-grooves 7L, 7R formed at intervals in the circumferential direction so as to be separated in the circumferential direction. The tread pattern is composed of the dar blocks 8L and 8R, the actual contact width of the tread 1 is W, the formation position (rib width) of the center rib 2 from the equator of the tread 1 is W1, and the left and right centers When the formation position of the main grooves 3L, 3R is (groove outer edge interval) W2, and the formation position (groove outer edge interval) of the left and right shoulder main grooves 4L, 4R is W3, W1 ≦ 0.1 × W, W2 ≦ The relational expression of 0.2 × W and W3 ≦ 0.7 × W is satisfied.
[0006]
In this way, the center rib 2 is formed on the equator to ensure steering stability, and the center rib 2 is formed in a zigzag shape on the left and right sides. The actual contact width of the tread 1 is W, and the equator of the tread 1 is formed. W1 is the position where the center rib 2 is formed, W2 is the position where the left and right center main grooves 3L and 3R are formed, and W3 is the position where the left and right shoulder main grooves 4L and 4R are formed. The snow performance is ensured by satisfying the relational expressions of W2 ≦ 0.2 × W and W3 ≦ 0.7 × W.
[0007]
Further, in claim 1 described above, the left and right blocks 6L, 6R are formed in the tread width direction so as to be separated by left and right communication grooves 10L, 10R connecting the left and right sub grooves 5L, 5R adjacent in the circumferential direction. It is recommended that the left and right sub-grooves 5L and 5R and the left and right communication grooves 10L and 10R constitute left and right side main grooves 11L and 11R that are continuous in a zigzag shape in the circumferential direction (Claim 2).
Furthermore, in claim 1 described above, left and right notch portions 9L and 9R that open to the left and right center main grooves 3L and 3R are formed in the left and right valley portions 2L and 2R that form the left and right zigzag shape of the center rib 2. (Claim 3).
[0008]
In this way, the snow performance is further improved by forming the left and right cut portions 9L, 9R.
In the first and second aspects described above, it is recommended that the left and right sub-grooves 5L and 5R are inclined grooves having an inclination angle with respect to the tire circumferential direction (claim 4).
Further, in claim 1 described above, the left and right shoulder sub-grooves 7L, 7R are lateral grooves whose longitudinal direction is the radial direction, and the width of the left and right shoulder sub-grooves 7L, 7R is the left and right shoulder main grooves. It is recommended that the part side communicating with 4L and 4R is narrow and the part side communicating with the left and right tread ends is wide.
[0009]
By adopting such a configuration, uneven wear can be suppressed and quietness can be secured.
Further, in claim 1, the sipe 12L, 12R along the longitudinal direction of the left and right sub-grooves 5L, 5R is formed on the ground contact surfaces of the left and right blocks 6L, 6R, and the left and right shoulder blocks 8L, It is recommended that sipes 13L and 13R along the longitudinal direction of the left and right shoulder sub-grooves 7L and 7R are formed on the ground contact surface of 8R (Claim 6).
[0010]
Thus, by forming the sipes 12L, 12R, 13L, and 13R on the contact surfaces of the left and right blocks 6L and 6R and the left and right shoulder blocks 8L and 8R, respectively, the block rigidity is optimized, and snow performance is improved and quietness is achieved. As a result, the steering stability is improved.
Further, in claim 1 described above, the left and right blocks 6L and 6R have two patterns in the circumferential direction as one pattern, and the left and right shoulder blocks 8L and 8R have three patterns in the circumferential direction as one pattern and are repeated in the circumferential direction. (Claim 7).
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1 showing a tread pattern of a pneumatic tire (pneumatic radial tire), a center rib 2 formed in a zigzag shape on the left and right continuously in the circumferential direction on the equator of the tread 1 (on the center in the tire width direction); The left and right center main grooves 3L and 3R formed in a left and right zigzag shape continuously in the circumferential direction on the left and right of the center rib 2, and the left and right shoulder main grooves formed on the left and right shoulders of the tread 1 in the circumferential direction. 4L, 4R and the left and right center main grooves 3L, 3R and the left and right shoulder main grooves 4L, 4R are connected to each other in the circumferential direction by the left and right sub grooves 5L, 5R formed at intervals in the circumferential direction. The left and right blocks 6L and 6R, the left and right shoulder main grooves 4L and 4R, and the left and right tread ends are connected to each other and the left and right tread ends are formed in the radial direction at intervals in the circumferential direction. Constitutes a tread pattern provided with a shoulder sub groove 7L, shoulder blocks 8L left and right quarantined formed in the circumferential direction by 7R, and 8R, the.
[0012]
In FIG. 1, the actual contact width of the tread 1 (referred to as an actual contact width at normal tire internal pressure (air pressure)) is W, and the formation position of the center rib 2 from the equator of the tread 1 (substantially corresponds to the rib width). W1, the formation positions of the left and right center main grooves 3L, 3R (referred to as the left and right maximum lengths from the equator or the groove outer edge spacing) W2, the formation positions of the left and right shoulder main grooves 4L, 4R (left and right from the equator) W1 = 0.1 × W, W2 ≦ 0.2 × W, W3 ≦ 0.7 × W, preferably W3 ≦ 0.72 × The relational expression of W is satisfied.
[0013]
By forming the center rib 2 at the center (on the equator) of the tread 1 in this way, while ensuring the steering stability (straight running performance), the center rib 2 has a zigzag shape on the left and right, and snow performance on an icy snowy road. In particular, left and right trough portions 9L and 9R that open to the left and right center main grooves 3L and 3R are formed in the left and right trough portions 2L and 2R that form the left and right zigzag shape of the center rib 2. As a result, the snow performance is further improved.
Further, the left and right blocks 6L and 6R are formed to be separated in the tread width direction by left and right communication grooves 10L and 10R that respectively connect the left and right sub grooves 5L and 5R adjacent in the circumferential direction. Left and right side main grooves 11L and 11R that are continuous in a zigzag shape in the circumferential direction are constituted by 5L and 5R and the left and right communication grooves 10L and 10R.
[0014]
In this way, the left and right side main grooves 11L and 11R are formed in a zigzag shape, and the left and right blocks (side blocks) 6L and 6R are separated and formed to ensure drainage on the wet road surface and The increase (increase) ensures the snow performance of the icy road.
The left and right sub-grooves 5L and 5R described above are inclined grooves having an inclination angle with respect to the tire circumferential direction, and the left and right shoulder sub-grooves 7L and 7R are lateral grooves whose longitudinal direction is a radial direction. The widths of the left and right shoulder sub-grooves 7L, 7R are narrow at the part connecting to the left and right shoulder main grooves 4L, 4R and wide at the part connecting to the left and right tread ends.
[0015]
Referring to FIG. 2, groove angles a and b with respect to the circumferential direction of the left and right center main grooves 3L and 3R, groove angles c and d with respect to the circumferential direction of the left and right side main grooves 11L and 11R, The groove angle e with respect to the circumferential direction of the shoulder main grooves 4L, 4R, the groove angle f with respect to the circumferential direction of the shoulder auxiliary grooves 7L, 7R, and the shoulder auxiliary grooves that isolate the left and right shoulder blocks 8L, 8R in the circumferential direction. The groove widths g ′, g, h ′, h, i ′, i of 7L and 7R will be described.
However, the groove angles a to f are clockwise angles at the center of the groove.
[0016]
That is, 185 ° ≦ a ≦ 215 °, 140 ° ≦ b ≦ 170 °, 130 ° ≦ c ≦ 160 °, 200 ° ≦ d ≦ 230 °, −20 ° ≦ e ≦ −5 °, 75 ° ≦ f ≦ 90 °, g ′ ≦ 0.6 g, h ′ ≦ 0.6 h, i ′ ≦ 0.75 i, i> 1.5 g, i> 1.5 h.
Further, at least the sipe 12L, 12R along the groove longitudinal direction of the left and right sub-grooves 5L, 5R is formed on the ground contact surface of the left and right blocks 6L, 6R, and on the ground contact surface of the left and right shoulder blocks 8L, 8R, Sipes 13L and 13R are formed along the longitudinal direction of the left and right shoulder sub-grooves 7L and 7R, and the left and right blocks 6L and 6R have two patterns in the circumferential direction as one pattern, and left and right shoulder blocks 8L. , 8R are repeatedly arranged in the circumferential direction with three in the circumferential direction as one pattern.
[0017]
In this way, by making the pattern with two center blocks 6L, 6R for three shoulder blocks 8L, 8R and forming sipes 12L, 12R, 13L, 13R in each block, the block rigidity can be optimized. It is possible to improve snow performance, ensure quietness, and improve steering stability. The auxiliary grooves 7L and 7R of the shoulder blocks 8L and 8R are arranged in the radial direction and the width is narrowed inside the ground. Thus, uneven wear can be suppressed.
Here, when the depth L1 of the sipes 12L and 12R formed on the ground contact surfaces of the left and right blocks 6L and 6R is the groove depth L2 of the center main grooves 3L and 3R, 0.2 × L2 ≦ L1 ≦ 0.9. × L2 is recommended for optimization of block rigidity, and the depth L3 of the sipes 13L and 13R formed on the ground contact surfaces of the left and right shoulder blocks 8L and 8R is the groove of the shoulder sub-grooves 7L and 7R. When the depth is L4, 0.2 × L4 ≦ L3 ≦ 0.9 × L4 is recommended in terms of optimizing the block rigidity.
[0018]
Each of the sipe 12L, 12R, 13L, and 13R described above is an open sipe whose both ends are open to the groove. However, both ends of the sipe 12L, 12R, 13L, and 13R are also open to the groove even in a semi-open sipe where one end is open in the groove and the other end is not open. A closed sipe that does not open may be used, and the shape of the sipe may be a waveform.
[0019]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a pneumatic tire with improved quietness and uneven wear resistance while ensuring off-road performance and snow performance.
[Brief description of the drawings]
FIG. 1 is a plan view showing a part of a tread pattern.
2 is a plan view showing a groove angle in the tread of FIG. 1; FIG.
[Explanation of symbols]
1 tread 2 center rib 3L, 3R center main groove 4L, 4R shoulder main groove 5L, 5R sub groove 6L, 6R block 7L, 7R shoulder sub groove 8L, 8R shoulder block

Claims (7)

A center rib (2) formed in a left and right zigzag shape continuously in the circumferential direction on the equator of the tread (1), and a left and right zigzag shape formed in a left and right zigzag shape continuously in the left and right of the center rib (2) Center main grooves (3L) (3R), left and right shoulder main grooves (4L) (4R) continuously formed in the circumferential direction on the left and right shoulders of the tread (1), and the left and right center main grooves (3L) (3R) and left and right shoulder main grooves (4L) (4R) are connected to the left and right sub-grooves (5L) (5R) formed at intervals in the circumferential direction and left and right blocks ( 6L) (6R), left and right shoulder main grooves (4L) (4R) and left and right shoulder sub-grooves (7L) (7R) formed by connecting the left and right tread ends and spaced in the circumferential direction Left and right formed in the circumferential direction The shoulder block (8L) (8R) is provided to form a tread pattern, the actual contact width of the tread (1) is (W), and the center rib (2) is formed from the equator of the tread (1). Position (rib width) is (W1), left and right center main grooves (3L) (3R) are formed (groove outer edge spacing) is (W2), and left and right shoulder main grooves (4L) (4R) are formed ( (W1) ≦ 0.1 × (W), (W2) ≦ 0.2 × (W), (W3) ≦ 0.7 × (W), where (Witch outer edge interval) is (W3) Pneumatic tire characterized by satisfying the formula. The left and right blocks (6L) (6R) are separated in the tread width direction by left and right communication grooves (10L) (10R) connecting the left and right auxiliary grooves (5L) (5R) adjacent in the circumferential direction. The left and right sub-grooves (5L) (5R) and the left and right communication grooves (10L) (10R) form left and right side main grooves (11L) (11R) that are continuous in a zigzag shape in the circumferential direction. A pneumatic tire characterized by The left and right notch portions (9L) opened in the left and right center main grooves (3L) (3R) in the left and right valley portions (2L) (2R) forming the left and right zigzag shape of the center rib (2) according to claim 1. ) (9R) is formed, the pneumatic tire characterized by the above-mentioned. 3. The pneumatic tire according to claim 1, wherein the left and right auxiliary grooves (5L) (5R) are inclined grooves having an inclination angle with respect to the tire circumferential direction. The left and right shoulder sub-grooves (7L) (7R) are lateral grooves whose longitudinal direction is a radial direction, and the widths of the left and right shoulder sub-grooves (7L) (7R) are as follows. A pneumatic tire characterized in that a portion side communicating with the main grooves (4L) (4R) is narrow and a portion side communicating with the left and right tread ends is wide. In Claim 1, the sipe (12L) (12R) along the groove longitudinal direction of the left and right sub-grooves (5L) (5R) is formed at least on the grounding surfaces of the left and right blocks (6L) (6R). Sipes (13L) (13R) along the longitudinal direction of the left and right shoulder sub-grooves (7L) (7R) are formed on the ground contact surface of the shoulder blocks (8L) (8R). Pneumatic tire. 2. The left and right blocks (6L) and (6R) have two patterns in the circumferential direction as one pattern, and the left and right shoulder blocks (8L) and (8R) have three patterns in the circumferential direction as one pattern in the circumferential direction. A pneumatic tire characterized by being arranged repeatedly.

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