JP4439658B2 - Pneumatic tire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire, and more specifically to a pneumatic radial tire in which a tread pattern is mainly configured by a rib base pattern.
[0002]
[Prior art]
In pneumatic tires, it is very difficult to maintain dry performance, wet grip performance, wear life, improve noise quietness and hydro performance, it is difficult to achieve both dry performance and wet performance, one of which is sacrificed It has become.
In other words, to improve hydro performance, increasing the groove area of the tire increases noise, and since the contact area decreases, using a high-grip rubber compound to ensure dry grip will result in a tire wear life. Will fall.
[0003]
For example, the tread pattern disclosed in Japanese Patent Publication No. 2-6644 and Japanese Patent Publication No. 2-6645 is mainly composed of a rib base tone pattern, and in particular, by giving directionality to the lateral groove, dry performance and wet performance. enhance limitations, improvement of wet toggle lip to increase the high-speed straight running stability, a pneumatic tire having improved straight running stability has been proposed (conventional example 1).
[0004]
Japanese Patent Application Laid-Open No. 11-189011 proposes a pneumatic tire in which a main groove is provided in a tire center, rib pattern regions are provided on the left and right sides of the main groove, and a shoulder pattern on the outer shoulder is used as a block pattern. Example 2).
[0005]
[Problems to be solved by the invention]
The pneumatic tire disclosed in the above publication has the following problems although its effectiveness is recognized as such.
That is, in the conventional example 1, the center rib (block) in the crown grounding portion (referring to the grounding portion in the center portion of the tread) in the tread grounding width (referring to the width that touches the road surface when mounted on a vehicle) ) Has a problem in that it is inferior in quietness due to the occurrence of air column resonance through the horizontal groove and causing noise.
[0006]
In addition, since the left and right shoulder contact portions are formed only with the block tone, there is a problem in steering performance, and air generated when the shoulder lateral groove is kicked up from the road surface (when the block edge is separated from the road surface). In addition to the problem that the emitted sound becomes a noise factor, there is a possibility that riding comfort may be reduced due to wear and vibration of the groove (block edge) of the groove.
[0007]
In the conventional pneumatic radial tire 2 of the conventional example, the crown grounding portion is a left and right rib tone, and the shoulder grounding portion is a block tone, so that the dry performance at the crown grounding portion can be improved, but the wet performance, particularly There is a problem in hydro performance, and if the left and right ribs are blocked by horizontal grooves in order to ensure hydro performance, there will be problems in noise, ride comfort and steering performance in the horizontal grooves and shoulder contact areas as in the previous example. there were.
[0008]
In the present invention, the tread pattern is configured with a rib base tone, and by combining or mixing the block base tone with this rib, the quietness of noise and the hydro performance are improved while maintaining dry performance, wet grip, and wear life, that is, An object of the present invention is to provide a pneumatic tire, particularly a pneumatic radial tire, in which dry performance and wet performance are made compatible without impairing riding comfort and operational stability.
[0009]
[Means for Solving the Problems]
The pneumatic tire according to the present invention is a pneumatic tire provided with a crown contact portion and left and right shoulder contact portions separated by vertical grooves extending in the tire circumferential direction on the left and right within the tread contact width. The crown contact portion is isolated via a center rib continuously extending in the circumferential direction on the tire equator and a longitudinal sub-groove continuously extending in the tire circumferential direction on the left and right of the center rib. Left and right side ribs, each of the left and right side ribs is provided with an inclined lateral groove that forms a block having a first ground contact portion and a rear ground contact portion at a predetermined pitch in the circumferential direction. Sipes along the inclined lateral grooves are formed on the ground contact surface, and the left and right shoulder ground contact portions are shoulder ribs that are continuously extended in the tire circumferential direction, Shoulder blocks separated by shoulder longitudinal grooves extending continuously in the tire circumferential direction on the outer side of the shoulder ribs and separated by a shoulder transverse groove extending in the width direction at a predetermined pitch in the circumferential direction. Each shoulder rib has a sipe formed on its grounding surface at the same or substantially the same pitch as the circumferential pitch of the shoulder lateral groove, and the sipe of every other shoulder rib in the circumferential direction is formed on the grounding surface of the shoulder rib. The shoulder rib is formed in the middle in the width direction of the shoulder rib.
[0010]
In this way, the crown ground contact portion (referred to as the center region in the tread width direction) is mainly composed of the center rib on the equator and the left and right side ribs, so that the crown ground contact portion becomes the rib tone and the straightness and the steering performance. On the other hand, the center rib remains in the rib base tone, and left and right side ribs are fused or mixed by inclined lateral grooves to ensure not only hydro performance but also dry performance, while noise performance is due to the remaining center rib. It is secured.
[0011]
Furthermore, the shoulder grounding part is not composed entirely of blocks, but is composed of shoulder ribs and shoulder blocks, and the right and left shoulder grounding parts also fuse or mix blocks in the rib base to improve steering performance. It improves the wear life and ensures riding comfort while achieving both noise characteristics.
The pneumatic tire according to the present invention is a pneumatic tire provided with a crown contact portion and left and right shoulder contact portions separated by vertical grooves extending in the tire circumferential direction on the left and right within the tread contact width. The crown contact portion is isolated via a center rib continuously extending in the circumferential direction on the tire equator and a longitudinal sub-groove continuously extending in the tire circumferential direction on the left and right of the center rib. Left and right side ribs, each of the left and right side ribs is provided with an inclined lateral groove that forms a block having a first ground contact portion and a rear ground contact portion at a predetermined pitch in the circumferential direction. Sipes along the inclined lateral grooves are formed on the ground contact surface, and the left and right shoulder ground contact portions are shoulder ribs that are continuously extended in the tire circumferential direction, Shoulder blocks separated by shoulder longitudinal grooves extending continuously in the tire circumferential direction on the outer side of the shoulder ribs and separated by a shoulder transverse groove extending in the width direction at a predetermined pitch in the circumferential direction. Each of the shoulder ribs has a sipe formed on the grounding surface at the same or substantially the same pitch as the circumferential width of the shoulder lateral groove, and the shoulder lateral groove has a larger or smaller groove width every other circumferential direction. groove width which is large in the previous carboxymethyl Yoruda lateral groove is larger in the range of 105 to 120% than the groove width is small.
[0012]
In the present invention, each of the center rib, the left and right side ribs, and the left and right shoulder ribs is extended in a straight line shape with a constant rib width in the tire circumferential direction, and the left and right side ribs, the left and right shoulder ribs, the center rib In this order, the rib width is narrower.
Furthermore, in the present invention, it is desirable that a narrow groove extending continuously in the tire circumferential direction is formed at the center width of the center rib.
[0013]
Further, in the pneumatic tire described above, the left and right inclined lateral grooves are inclined such that a portion opening to the left and right vertical sub-grooves is a first arrival side, and a portion opening to the left and right vertical grooves is inclined to a rear arrival side. It is recommended that a drainage introduction portion that opens in an expanded shape toward the left and right vertical sub-grooves is formed on the first arrival side of the horizontal groove.
Thus, the drainage introduction part is formed in the left and right vertical sub-grooves, so that the drainage performance at the crown grounding part is improved.
[0014]
Furthermore, in the pneumatic tire described above, the inclination angle of the left and right inclined lateral grooves with respect to the tire circumferential direction is 30 to 70 degrees, and the groove width of the lateral grooves is 2 to 8% of the circumferential pitch (PW). It is recommended that
In the pneumatic tire described above, it is desirable that the block is separated into three pieces in the circumferential direction by sipes formed on the contact surfaces of the left and right blocks.
[0015]
By configuring in this way, the block rigidity is not greatly reduced, and the wet performance is improved by improving the traction / brake property on the wet road surface by the sipe effect while maintaining the dry performance.
Furthermore, it is recommended that the shoulder lateral groove that separates the left and right shoulder blocks in the circumferential direction is formed so as to be substantially along the tire axial direction that is inclined at an angle of 60 to 90 degrees with respect to the tire circumferential direction. The
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a front view of a pneumatic tire 1 according to the present invention as a pneumatic radial tire, and FIG. 2 is a plan view showing a part of the tread pattern (partly expanding the left and right shoulders). is there.
[0017]
1 and 2, a pneumatic tire 1 according to the present invention extends within a tread contact width W in a linear form (while maintaining a constant width) in the tire circumferential direction on the left and right sides of the crown contact portion 2 in the figure. The left and right shoulder grounding portions 3L and 3R are separated by the vertical grooves 4L and 4R.
The crown ground contact portion 2 has a center rib 5 continuously extended in a straight line with a constant width in the circumferential direction on the tire equator OO, and a constant width in the tire circumferential direction on the left and right of the center rib 5. The left and right side ribs 6L and 6R are separated by vertical sub-grooves 7L and 7R that are continuously extended in a linear form.
[0018]
Each of the left and right side ribs 6L and 6R is an inclined lateral groove 9L that forms a block having first landing parts 8L-1 and 8R-1 and rear landing parts 8L-2 and 8R-2 at a predetermined pitch PW in the 8L and 8R circumferential directions. 9R, and sipes 10L and 10R having a groove width of 0.3 to 1.5 mm along the inclined lateral grooves 9L and 9R are formed on the grounding surfaces of the blocks 8L and 8R, respectively.
[0019]
Here, the first ground contact portions 8L-1 and 8R-1 of the left and right blocks 8L and 8R refer to portions that are grounded first on the road surface when the tire 1 rotates in the direction of the arrow T (forward travel) on the road surface. In contrast, the rear landing parts 8L-2 and 8R-2 refer to parts that are grounded later (delayed).
The center rib 5 is formed with a narrow groove 5A extending continuously in the tire circumferential direction at the center of the rib width, and groove widths 0.3 to 1... Formed on the ground contact surfaces of the left and right blocks 8L and 8R. The relatively large blocks 8L and 8R are separated (separated) into three substantially equal blocks in the circumferential direction by the 5 mm sipes 10L and 10R.
[0020]
As a result, the wet performance (driving force and braking force when traveling on a wet road surface) is improved by the sipe effect while maintaining the dry performance without greatly reducing the block rigidity, and the center rib 5 is thereby capable of traveling ( (Including both dry and wet), the responsiveness at the time of small rudder (preventing left and right shaking) is maintained.
[0021]
Further, the left and right shoulder ground contact portions 3L and 3R are provided with left and right shoulder ribs 11L and 11R that are continuously extended in the tire circumferential direction and are stretched in a straight line shape, and on the outer side of the ribs in the tire circumferential direction. Shoulder blocks 12L and 12R which are separated by shoulder longitudinal grooves 13L and 13R having a groove width of 0.5 to 3.00 mm and continuously separated by shoulder lateral grooves 14L and 14R at a predetermined circumferential direction pitch. It is configured.
[0022]
The left and right shoulder ribs 11L, 11R have sipes 15L, having a groove width of 0.3 to 1.5 mm on the ground contact surface at the same or substantially the same pitch as the circumferential pitch of the shoulder lateral grooves 14L, 14R. 15R is formed, and left and right shoulder ribs 11L and 11R that are relatively close to the rib shape are unevenly worn and patterned in the same manner as the left and right blocks 8L and 8R constituting the left and right side ribs 6L and 6R in the crown grounding portion 2 described above. Noise is suppressed in both the crown grounding portion 2 and the shoulder grounding portions 3L, 3R, and the sipe 10L, 10R, 15L, 15R improves wet performance (driving force and braking force on the wet road surface), and block rigidity is improved. This reduces the road noise.
[0023]
Here, the blocks 8L and 8R in the left and right side ribs 6L and 6R in the crown ground contact portion 2 are divided into three in the repeated width (PW) by the sipes 10L and 10R, whereas the shoulders in the shoulder ground contact portions 3L and 3R. The blocks 12L, 12R, etc. are divided into two in the repetition width (PW), and these blocks 8L, 8R, 12L, 12R have a block pattern in which the left and right blocks are shifted in the circumferential direction on the equator OO. ing.
[0024]
Further, as is apparent from FIG. 2, the center rib 5, the left and right side ribs 6L and 6R, and the left and right shoulder ribs 11L and 11R are each extended in a straight line form with a constant rib width in the tire circumferential direction. The left and right side ribs 6L and 6R, the left and right shoulder ribs 11L and 11R, and the center rib 5 are narrowed in this order.
[0025]
That is, on both sides of the tire equator plane, left and right vertical sub-grooves 7L and 7R are provided in W1 within a range of 5% to 12% from the tire equator line OO with respect to the tire contact width (tread contact width) W. The left and right vertical grooves 4L and 4R are provided in the W2 within the W ratio range of 15% to 30%, the left and right shoulder vertical grooves 13L and 13R are provided in the W3 within the W ratio range of 30% to 40%, and the groove width. Hydro performance is improved by setting G2 to a width of 110% to 160% of the groove width G1 (G1 <G2).
[0026]
Further, as shown in FIG. 2, the left and right inclined lateral grooves 9L and 9R have a portion that opens to the left and right vertical sub-grooves 7L and 7R on the first arrival side, and a portion that opens to the left and right vertical grooves 4L and 4R on the rear arrival side. Drainage introduction portions 9L-1 and 9R-1 are formed on the first arrival side of the left and right inclined lateral grooves 9L and 9R. The drainage introduction portions 9L-1 and 9R-1 open in an expanded shape toward the left and right vertical auxiliary grooves 7L and 7R. In addition, the inclination angle α of the left and right inclined lateral grooves 9L and 9R with respect to the tire circumferential direction is 30 to 70 degrees, and the groove width M1 of the lateral grooves is 2 to 8% of the circumferential pitch (PW). Yes.
[0027]
Further, the shoulder lateral grooves 14L, 14R that separate the left and right shoulder blocks 12L, 12R in the circumferential direction have an inclination angle γ of 60 to 90 degrees with respect to the tire circumferential direction, and are formed along the tire axial direction. Has been.
Further, shoulder lateral grooves 14L and 14R are arranged in the longitudinal direction of the sipes 15L and 15R formed at the ground contact surfaces of the left and right shoulder ribs 11L and 11R with an inclination angle β of 60 to 90 degrees with respect to the circumferential direction. 15L and 15R are cut in the circumferential direction of the shoulder ribs 11L and 11R from the middle of the width direction of the shoulder ribs 11L and 11R through the shoulder longitudinal grooves 13L and 13R, and the notches 15L-1 and 15R-1 connected to the shoulder lateral grooves 14L and 14R. It is formed on the ground plane.
[0028]
Also, the left and right shoulder lateral grooves 14L, 14R are alternated in the circumferential direction, and the groove widths M2, M3 are large and small (M2 is 3-10% of W, M3 is 70-90% of M2). The shoulder lateral grooves 14L and 14R have different groove widths M2 and M3, so that air column resonance is suppressed and canceled to ensure quietness in the shoulder blocks 12L and 12R, and the cut portions 15L-1 and 15R- By increasing the groove width M2 of the shoulder lateral grooves 14L, 14R with 1 in a range of 105 to 120%, the dispersion of pattern noise is increased (widened), and the quietness is improved.
[0029]
Further, the left and right shoulder longitudinal grooves 13L and 13R having groove widths of 0.5 to 3.00 mm are reinforced at the bottoms of the grooves in a range of 10 to 15% of the groove depth D as shown in FIG. 17L and 17R are provided in the circumferential length S of the shoulder blocks 12L and 12R (in the illustrated example, the front and rear in the circumferential direction of the blocks 12L and 12R as shown in FIG. 2), and the groove width M3 of the left and right shoulder lateral grooves 14L and 14R is small. As shown in FIG. 4, the shoulder lateral grooves 14L and 14R of the shoulder lateral grooves 14L and 14R have reinforcing portions 18L and 18R which are raised in a trapezoidal shape within a range of 10 to 50% of the groove depth D1, as shown in FIG. It is provided in the middle of the lateral grooves 14L and 14R, specifically, in the range of 40 to 50% from the equator OO).
[0030]
In this way, by reinforcing the reinforcing portions 17L, 17R, 18L, and 18R from the bottom of the groove, the block rigidity of the left and right shoulder blocks 12L and 12R is maintained, and quietness is suppressed while suppressing uneven wear while maintaining steering stability. It is improving the nature.
For the sipes 10L, 10R, 15L, and 15R, as exemplified by the sipes 15L and 15R in FIG. 5, the groove bottoms are formed in flask-like (bulb-like) stress relief portions 15L-2 and 15R-2. Thus, the wet performance after wear (smooth drainage) is maintained while avoiding stress concentration at the groove bottom.
[0031]
Although the embodiment of the pneumatic tire 1 according to the present invention is as described above, various design changes are possible.
For example, G1 ≧ G2, or the center rib 5 may meander in the width direction or be in a rib shape.
[0032]
【The invention's effect】
As described in detail above, according to the present invention, while maintaining the handling stability and the wear life without changing the tread rubber (material), both hydro performance and dry performance can be achieved, quietness can be improved and uneven wear can be achieved. Can be suppressed.
[Brief description of the drawings]
FIG. 1 is a front view of a pneumatic tire according to the present invention.
FIG. 2 is a plan view illustrating a part of the tread portion of FIG.
FIG. 3 is an enlarged cross-sectional view of a portion indicated by an arrow C in FIG.
4 is an enlarged cross-sectional view of a portion indicated by an arrow B in FIG.
5 is an enlarged cross-sectional view of a portion indicated by an arrow E in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Crown grounding part 3L, 3R Shoulder grounding part 4L, 4R Vertical groove 5 Center rib 6L, 6R Side rib 7L, 7R Vertical subgroove 8L, 8R Left and right center block 9L, 9R Inclined horizontal groove 10L, 10R Sipe 11L, 11R Shoulder ribs 12L, 12R Shoulder blocks 15L-1, 15R-1 Notch

Claims (8)

In a pneumatic tire including a crown grounding portion and left and right shoulder grounding portions separated by a longitudinal groove extending in the tire circumferential direction on the left and right within the tread grounding width,
The crown contact portion is isolated via a center rib continuously extending in the circumferential direction on the tire equator and a vertical sub-groove continuously extending in the tire circumferential direction on the left and right of the center rib. It consists of left and right side ribs,
Each of the left and right side ribs includes inclined lateral grooves that form blocks having a first landing part and a rear landing part at a predetermined circumferential pitch,
Each of these blocks has a sipe along the inclined lateral groove formed on its grounding surface,
The left and right shoulder grounding portions are
Shoulder ribs that are continuously stretched in the tire circumferential direction;
A shoulder block separated by a shoulder longitudinal groove extending continuously in the tire circumferential direction on the outer side of the shoulder rib and separated by a shoulder lateral groove extending in the width direction at a predetermined pitch in the circumferential direction;
In each of the left and right shoulder ribs, sipes are formed on the ground contact surface at the same or substantially the same pitch as the circumferential pitch of the shoulder lateral grooves,
The sipe of every other shoulder rib in the circumferential direction is formed in the ground contact surface of the shoulder rib and is continuous with a cut portion connected to the shoulder lateral groove in the middle in the width direction of the shoulder rib. In a pneumatic tire including a crown grounding portion and left and right shoulder grounding portions separated by a longitudinal groove extending in the tire circumferential direction on the left and right within the tread grounding width,
The crown contact portion is isolated via a center rib continuously extending in the circumferential direction on the tire equator and a vertical sub-groove continuously extending in the tire circumferential direction on the left and right of the center rib. It consists of left and right side ribs,
Each of the left and right side ribs includes inclined lateral grooves that form blocks having a first landing part and a rear landing part at a predetermined circumferential pitch,
Each of these blocks has a sipe along the inclined lateral groove formed on its grounding surface,
The left and right shoulder grounding portions are
Shoulder ribs that are continuously stretched in the tire circumferential direction;
A shoulder block separated by a shoulder longitudinal groove extending continuously in the tire circumferential direction on the outer side of the shoulder rib and separated by a shoulder lateral groove extending in the width direction at a predetermined pitch in the circumferential direction;
In each of the left and right shoulder ribs, sipes are formed on the ground contact surface at the same or substantially the same pitch as the circumferential pitch of the shoulder lateral grooves,
The width of the shoulder lateral groove is large every other circumferential direction,
A pneumatic tire large and is a groove width, characterized in that it is largely in the range of from 105 to 120% than the groove width is small before carboxymethyl Yoruda lateral groove. Each of the center rib, the left and right side ribs, and the left and right shoulder ribs is stretched in a straight line form with a constant rib width in the tire circumferential direction,
The pneumatic tire according to claim 1 or 2, wherein a rib width is narrowed in the order of the left and right side ribs, the left and right shoulder ribs, and the center rib. The pneumatic tire according to any one of claims 1 to 3, wherein a narrow groove extending continuously in a tire circumferential direction is formed at the center width of the center rib. The left and right inclined lateral grooves are inclined such that a portion opening to the left and right vertical sub-grooves is a first arrival side, and a portion opening to the left and right vertical grooves is a rear arrival side,
The drainage introduction part which opens as an expanding shape toward the left and right vertical sub-grooves is formed on the first arrival side of the left and right inclined lateral grooves. Pneumatic tires. The inclination angle of the left and right inclined lateral grooves with respect to the tire circumferential direction is 30 to 70 degrees,
The pneumatic tire according to any one of claims 1 to 5, wherein a groove width of the inclined lateral groove is 2 to 8% of a circumferential pitch (PW) thereof. The pneumatic tire according to any one of claims 1 to 6, wherein the blocks are separated into three pieces in a circumferential direction by sipes formed on the ground contact surfaces of the left and right blocks. The shoulder lateral groove that separates the left and right shoulder blocks in the circumferential direction is formed in a shape substantially along the tire axial direction that is inclined at an angle of 60 to 90 degrees with respect to the tire circumferential direction. Item 10. The pneumatic tire according to any one of Items 1 to 7.

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