WO2015029861A1

WO2015029861A1 - Tire

Info

Publication number: WO2015029861A1
Application number: PCT/JP2014/071832
Authority: WO
Inventors: 達生土屋
Original assignee: 株式会社ブリヂストン
Priority date: 2013-08-29
Filing date: 2014-08-21
Publication date: 2015-03-05
Also published as: JP2015044527A; CN104417279B; CN204095411U; CN104417279A

Abstract

A tire (1) has a sub circumferential groove (30) and a plurality of outer lug grooves (40Aout) intersecting with the sub circumferential groove (30). The sub circumferential groove (30) has an inclined surface (33) which is continuously inclined from deepest portions (32) corresponding to the portions where the outer lug grooves (40Aout) intersect the sub circumferential groove (30), toward shallowest portions (31) of the sub circumferential groove (30) positioned between adjacent outer lug grooves (40Aout).

Description

tire

The present invention relates to a tire including a tread portion having a tread contact surface.

Conventionally, a tire having a pair of bead portions assembled to a rim flange, a pair of side portions continuous to the pair of bead portions on the outer side in the tire radial direction, and a tread portion having a tread ground contact surface that contacts the road surface. It has been known.

In such a tire, the tread portion (tread contact surface) has a plurality of circumferential grooves extending along the tire circumferential direction and a plurality of widthwise grooves extending along the tire width direction.

Here, the plurality of circumferential grooves include a main circumferential groove and a sub circumferential groove. The sub circumferential groove is located on the outer side in the tire width direction with respect to the main circumferential groove. The plurality of width direction grooves include a width direction groove that communicates with the main circumferential direction groove and the sub circumferential direction groove, a width direction groove that communicates with the sub circumferential direction groove, and reaches the tread grounding end.

According to such a tire, drainage performance is ensured by the width direction groove reaching the tread grounding end (for example, Patent Document 1).

JP 2006-240592 A

However, in the above-described tire, the groove in the width direction reaching the tread grounding end is formed in communication with the sub-circumferential groove, so that the rigidity of the land portion provided in the shoulder portion is reduced and steering stability is lowered. There is a fear.

On the other hand, it is necessary to improve not only drainage performance (wet performance) but also wear resistance performance and steering stability in a tire (for example, a sports tire) mounted on an SUV or the like.

Therefore, the present invention has been made to solve the above-described problems, and provides a tire that can improve wear resistance and steering stability while suppressing a decrease in drainage performance (wet performance). The purpose is to provide.

The tire according to the first feature includes a tread portion having a tread contact surface that contacts the road surface. The tread portion includes a plurality of circumferential grooves extending along the tire circumferential direction and a plurality of width direction grooves extending along the tire width direction on the tread contact surface. The plurality of circumferential grooves include a main circumferential groove and a sub circumferential groove positioned on the outer side in the tire width direction with respect to the main circumferential groove. The plurality of widthwise grooves cross the sub circumferential groove. One end of each of the plurality of widthwise grooves communicates with the main circumferential groove. The sub-circumferential groove includes a sub-circumferential groove bottom positioned between a pair of adjacent width-direction grooves from a groove bottom position corresponding to a portion where the width-direction groove crosses the sub-circumferential groove. It has the inclined surface which inclines continuously toward the top surface.

In the first feature, the other end of each of the plurality of widthwise grooves terminates in the shoulder land portion without reaching the tread ground contact end.

In the first feature, the groove width of the sub circumferential groove is narrower than the groove width of the main circumferential groove, and in the tire radial direction, the depth of the sub circumferential groove is the main circumferential direction. Shallow than the depth of the groove.

In the first feature, in the tire radial direction, the depth of the sub circumferential groove is not less than 40% and not more than 55% of the depth of the main circumferential groove.

In the first feature, in the tire radial direction, the depth of the plurality of widthwise grooves is shallower than the depth of the main circumferential groove.

In the first feature, in the tire circumferential direction, the length of the top surface of the sub circumferential groove bottom is equal to the length of the inclined surface.

1st characteristic WHEREIN: The pattern comprised by the groove | channel provided in the said tread part is asymmetrical on the basis of a tire equator line. The sub-circumferential groove is located on the outer side of the vehicle with respect to the tire equator line when the tire is mounted on the vehicle.

According to the present invention, it is possible to provide a tire that can improve wear resistance and steering stability while suppressing a decrease in drainage performance (wet performance).

FIG. 1 is a diagram illustrating a tread contact surface of the tire 1 according to the first embodiment. FIG. 2 is a diagram illustrating the sub circumferential groove 30 according to the first embodiment.

Hereinafter, a tire according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Outline of Embodiment]
A tire is provided with a tread part which has a tread grounding surface which contacts a road surface in an embodiment. The tread portion includes a plurality of circumferential grooves extending along the tire circumferential direction and a plurality of width direction grooves extending along the tire width direction on the tread contact surface. The plurality of circumferential grooves include a main circumferential groove and a sub circumferential groove positioned on the outer side in the tire width direction with respect to the main circumferential groove. The plurality of widthwise grooves cross the sub circumferential groove. One end of each of the plurality of widthwise grooves communicates with the main circumferential groove.

In the sub circumferential groove, the sub circumferential groove bottom located between a groove bottom position corresponding to a portion where the width groove intersects the sub circumferential groove and a pair of adjacent width grooves. And the top surface. Here, the “groove bottom position” is the deepest portion having the deepest depth in the tire radial direction, and has a plane parallel to the tread installation surface. The “top surface of the sub-circumferential groove bottom” is the shallowest portion having the shallowest depth in the tire radial direction and has a plane parallel to the tread installation surface. The sub circumferential groove has an inclined surface that continuously inclines from the groove bottom position toward the top surface of the sub circumferential groove bottom. The top surface (the shallowest part) and the groove bottom position (the deepest part) of the sub circumferential groove bottom are alternately repeated in the tire circumferential direction via an inclined surface.

In the embodiment, the sub circumferential groove includes a shallowest portion and a deepest portion, and the deepest portion is located in a portion where each of the plurality of width direction grooves crosses the sub circumferential groove. That is, since the width direction groove traverses the deepest portion of the sub circumferential direction groove, a decrease in drainage performance (wet performance) is suppressed. On the other hand, by providing the shallowest portion, the rigidity of the portion where the sub circumferential groove is formed (that is, the shoulder portion) is increased, so that the wear resistance and the steering stability can be improved.

[First Embodiment]
(Tire composition)
Hereinafter, the tire according to the first embodiment will be described. FIG. 1 is a diagram illustrating a tread contact surface of the tire 1 according to the first embodiment.

Here, the tire 1 includes a pair of bead portions assembled to the rim flange, a side portion continuous to the pair of bead portions outside the tire radial direction TR, and a tread portion having a tread ground contact surface that contacts the road surface. Have

Here, the pattern formed by the grooves provided in the tread portion 10 (tread contact surface) is asymmetric with respect to the tire equator line CL as shown in FIG. Hereinafter, in a state where the tire 1 is mounted on the vehicle, the outside of the vehicle from the tire equator line CL is referred to as “vehicle outside”, and the inside of the vehicle from the tire equator line CL is referred to as “vehicle inside”.

Further, as shown in FIG. 1, the tread ground contact width is represented by W, and the tread ground contact length is represented by L. In a state where the tire 1 is mounted on a regular rim specified in JATMA, the internal pressure of the tire 1 is the normal internal pressure specified in JATMA, and the load of the tire 1 is 80% of the maximum load load specified in JATMA. The contact width W and the tread contact length L are measured.

As shown in FIG. 1, the tire 1 has a tread portion 10 having a tread contact surface. The tread portion 10 includes a center portion 10C, a shoulder portion 10Sout, and a shoulder portion 10Sin. Further, the tread portion 10 (tread contact surface) includes a plurality of main circumferential grooves 20 extending along the tire circumferential direction TC, a sub circumferential groove 30 extending along the tire circumferential direction TC, and a tire on the tread contact surface. And a plurality of width direction grooves 40 extending along the width direction TW.

The center part 10C is a part straddling the tire equator line CL. The center portion 10C is not particularly limited, but the main circumferential groove 20 (outer circumferential groove 20out) located on the outermost side of the vehicle and the main circumferential groove 20 (inner circumferential groove 20in) located on the innermost side of the vehicle. ) Between. The center portion 10C is a portion that continues along the tire circumferential direction TC.

The shoulder portion 10Sout is a portion provided outside the center portion 10C of the vehicle. The shoulder portion 10Sin is not particularly limited, but is a portion between the tread ground contact end 10Eout located on the vehicle outer side and the main circumferential groove 20 (outer circumferential groove 20out) located on the outermost vehicle side. The shoulder portion 10Sout is a portion that continues along the tire circumferential direction TC.

The shoulder portion 10Sin is a portion provided on the vehicle inner side of the center portion 10C. The shoulder portion 10Sin is not particularly limited, but is a portion between the tread grounding end 10Ein located on the vehicle inner side and the main circumferential groove 20 (inner circumferential groove 20in) located on the innermost side of the vehicle. The shoulder portion 10Sin is a portion that continues along the tire circumferential direction TC.

The plurality of main circumferential grooves 20 include a center circumferential groove 20c, an outer circumferential groove 20out, and an inner circumferential groove 20in. The center circumferential groove 20c is provided in the center portion 10C. The outer circumferential groove 20out is located on the vehicle outer side with respect to the center circumferential groove 20c. The inner circumferential groove 20in is located on the vehicle inner side with respect to the center circumferential groove 20c.

The sub circumferential groove 30 is located on the outer side in the tire width direction TW with respect to the outer circumferential groove 20out. In the first embodiment, the sub circumferential groove 30 is located on the vehicle outer side with respect to the outer circumferential groove 20out.

The plurality of width direction grooves 40 include a center lug groove 40Ac, a center lug groove 40Bc, an outer lug groove 40Aout, an outer lug groove 40Bout, an outer lug groove 40Cout, an inner lug groove 40Ain, and an inner lug groove 40Bin.

The center lug grooves 40Ac that are a part of the plurality of width direction grooves 40 are arranged at predetermined intervals in the tire circumferential direction TC. One end of the center lug groove 40Ac communicates with the center circumferential groove 20c, and the other end of the center lug groove 40Ac does not reach the outer circumferential groove 20out and terminates in the center portion 10C (center land portion). .

The center lug grooves 40Bc that are a part of the plurality of width direction grooves 40 are arranged at predetermined intervals in the tire circumferential direction TC. One end of the center lug groove 40Bc communicates with the inner circumferential groove 20in, and the other end of the center lug groove 40Bc terminates in the center portion 10C (center land portion) without reaching the center circumferential groove 20c. .

Here, in the tire circumferential direction TC, the interval between the pair of adjacent center lug grooves 40Ac is preferably the same as the interval between the pair of adjacent center lug grooves 40Bc.

The outer lug grooves 40Aout that are a part of the plurality of width direction grooves 40 are arranged at predetermined intervals in the tire circumferential direction TC. The outer lug groove 40 Aout crosses the sub circumferential groove 30. One end of the outer lug groove 40Aout communicates with the outer circumferential groove 20out, and the other end of the outer lug groove 40Aout terminates in the shoulder portion 10Sout (shoulder land portion) without reaching the tread grounding end 10Eout.

In addition, an outer lug groove 40 Cout (first outer width direction groove) and an outer lug groove 40 Bout (second outer side) that extend along the tire width direction and have one end reaching the tread grounding end are partially formed in the plurality of width direction grooves 40. Width direction groove).

The outer lug grooves 40Bout are arranged at predetermined intervals in the tire circumferential direction TC. One end of the outer lug groove 40Bout opens to the tread grounding end 10Eout, and the other end of the outer lug groove 40Bout does not reach the sub circumferential groove 30 and terminates in the shoulder portion 10Sout (shoulder land portion).

Here, in the tire circumferential direction TC, the interval between the pair of outer lug grooves 40Bout adjacent to each other is preferably the same as the interval between the pair of center lug grooves 40Ac adjacent to each other.

The outer lug grooves 40Cout are arranged at predetermined intervals in the tire circumferential direction TC. One end of the outer lug groove 40Cout opens to the tread grounding end 10Eout, and the other end of the outer lug groove 40Cout does not reach the sub circumferential groove 30 and terminates in the shoulder portion 10Sout (shoulder land portion).

Here, the outer lug groove 40Cout preferably extends along the direction of the extension of the outer lug groove 40Aout. In other words, in the tire circumferential direction TC, the interval between the pair of outer lug grooves 40Aout adjacent to each other is preferably the same as the interval between the pair of outer lug grooves 40Cout adjacent to each other.

The outer lug groove 40Cout and the outer lug groove 40Bout have different lengths in the tire width direction, and the length of the outer lug groove 40Cout is shorter than the length of the outer lug groove 40Bout. The outer lug grooves 40Bout and the outer lug grooves 40Cout are alternately arranged in the tire circumferential direction TC. That is, the outer lug groove 40Bout is positioned between a pair of outer lug grooves 40Cout adjacent in the tire circumferential direction, and the outer lug groove 40Cout is positioned between a pair of outer lug grooves 40Bout adjacent in the tire circumferential direction. To do.

The inner lug grooves 40Ain which are a part of the plurality of width direction grooves 40 are arranged at predetermined intervals in the tire circumferential direction TC. One end of the inner lug groove 40Ain opens to the tread grounding end 10Ein, and the other end of the inner lug groove 40Ain does not reach the inner circumferential groove 20in and terminates in the shoulder portion 10Sin (shoulder land portion). At the other end of the inner lug groove 40Ain, a circumferential sipe 50 extending from the other end of the inner lug groove 40Ain along the tire circumferential direction TC is formed.

Here, in the tire circumferential direction TC, the interval between the pair of adjacent inner lug grooves 40Ain is preferably the same as the interval between the pair of adjacent center lug grooves 40Bc.

The inner lug grooves 40Bin which are a part of the plurality of width direction grooves 40 are arranged at predetermined intervals in the tire circumferential direction TC. One end of the inner lug groove 40Bin opens to the tread grounding end 10Ein, and the other end of the inner lug groove 40Bin terminates in the shoulder portion 10Sin (shoulder land portion) without reaching the inner circumferential groove 20in.

Here, in the tire width direction TW, the length of the inner lug groove 40Bin is shorter than the length of the inner lug groove 40Ain. The inner lug grooves 40Ain and the inner lug grooves 40Bin are alternately arranged in the tire circumferential direction TC.

In the first embodiment, the groove width of the sub circumferential groove 30 is preferably narrower than the groove width of the main circumferential groove 20 (center circumferential groove 20c, outer circumferential groove 20out, and inner circumferential groove 20in). Here, the groove width is a width in a direction orthogonal to the direction in which the groove extends.

In the tire radial direction TR, the depth of the sub circumferential groove 30 is preferably shallower than the depth of the main circumferential groove 20 (center circumferential groove 20c, outer circumferential groove 20out, and inner circumferential groove 20in). Specifically, in the tire radial direction TR, the depth of the sub circumferential groove 30 is preferably 40% or more and 55% or less of the depth of the main circumferential groove 20. Here, regarding the comparison of the depth in the tire radial direction TR of the sub circumferential groove 30 and the main circumferential groove 20, the maximum depth (for example, Dmax) of each groove may be compared, and the minimum depth of each groove may be compared. (For example, Dmin), or the average depth of each groove may be compared.

In the tire radial direction TR, the depth of the outer lug groove 40Aout is preferably shallower than the depth of the main circumferential groove 20 (center circumferential groove 20c, outer circumferential groove 20out, and inner circumferential groove 20in). Here, the comparison of the depth of the outer lug groove 40Aout and the main circumferential groove 20 in the tire radial direction TR may be made at the maximum depth of each groove, or may be made at the minimum depth of each groove. Of course, the average depth of each groove may be compared.

(Sub circumferential groove configuration)
Hereinafter, the sub circumferential groove according to the first embodiment will be described. FIG. 2 is a diagram illustrating the sub circumferential groove 30 according to the first embodiment. 2 is a cross-sectional view taken along the line AA shown in FIG.

As shown in FIG. 2, the sub circumferential groove 30 has the shallowest depth (top surface of the sub circumferential groove bottom) 31 having the shallowest depth in the tire radial direction TR and the deepest depth in the tire radial direction TR. And the deepest portion (groove bottom position of the sub circumferential groove bottom) 32. The shallowest portion 31 and the deepest portion 32 are alternately repeated in the tire circumferential direction TC.

The shallowest portion 31 is a top surface of a sub circumferential groove bottom located between a pair of outer lug grooves 40Aout adjacent to each other in the tire circumferential direction TC. The deepest portion 32 is a groove bottom position corresponding to a portion where the plurality of outer lug grooves 40 Aout cross the sub circumferential groove 30.

In the first embodiment, the sub-circumferential groove 30 has an inclined surface 33 that continues from the groove bottom of the deepest portion 32 to the top surface (or groove bottom) of the shallowest portion 31 adjacent to the deepest portion 32. In the tire circumferential direction TC, the length L1 of the shallowest portion 31 is preferably substantially equal to the length L2 of the inclined surface 33. As a result, the decrease in the flow of water (that is, drainage performance) from the sub circumferential groove 30 to the outer lug groove 40Aout is suppressed, and the rigidity of the portion where the sub circumferential groove 30 is formed (that is, the shoulder portion 10Sout) is reduced. It is possible to achieve both suppression. In addition, the flow of water in the tire circumferential direction TC can also be secured in the sub circumferential groove 30.

(Function and effect)
In the first embodiment, the sub circumferential groove 30 includes a shallowest portion 31 and a deepest portion 32, and the deepest portion 32 is located at a portion where each of the plurality of outer lug grooves 40 Aout crosses the sub circumferential groove 30. . That is, since the outer lug groove 40Aout crosses the deepest portion 32 of the sub circumferential groove 30, a decrease in drainage performance (wet performance) is suppressed. On the other hand, by providing the shallowest portion 31, the rigidity of the portion where the sub circumferential groove 30 is formed (that is, the shoulder portion 10Sout) is increased, so that the wear resistance and the steering stability can be improved.

In the first embodiment, the other end of the outer lug groove 40Aout terminates in the shoulder portion 10Sout (shoulder land portion) without reaching the tread grounding end 10Eout. Accordingly, since the rigidity of the portion where the outer lug groove 40Aout is formed (that is, the shoulder portion 10Sout) is further increased, the wear resistance performance and the steering stability can be further improved.

In the first embodiment, since the groove width of the sub circumferential groove 30 is narrower than the groove width of the main circumferential groove 20, and the depth of the sub circumferential groove 30 is shallower than the depth of the main circumferential groove 20, the sub circumferential direction A reduction in rigidity of a portion where the groove 30 is formed (that is, the shoulder portion 10Sout) is suppressed.

In the first embodiment, since the depth of the outer lug groove 40Aout is shallower than the depth of the main circumferential groove 20, a decrease in rigidity of a portion where the outer lug groove 40Aout is formed (that is, the shoulder portion 10Sout) is suppressed. .

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

In the embodiment, the case where the pattern formed by the grooves provided in the tread portion 10 (tread contact surface) is asymmetric with respect to the tire equator line CL is illustrated. However, the embodiment is not limited to this. For example, the pattern formed by the grooves provided in the tread portion 10 (tread contact surface) may be symmetric with respect to the tire equator line CL. In such a case, since there is no distinction between the vehicle inner side and the vehicle outer side, the sub circumferential groove 30 only needs to be provided in the shoulder portion.

In the embodiment, the groove bottom of the sub circumferential groove 30 is constituted by the groove bottom of the shallowest portion 31, the groove bottom of the deepest portion 32, and the inclined surface 33, and the radial cross section along the tire circumferential direction forms a trapezoid. Yes. In other words, the groove bottom of the sub circumferential groove 30 is raised in a trapezoidal shape as shown in FIG. However, the embodiment is not limited to this. For example, the groove bottom of the sub circumferential groove 30 may have a waveform shape along the tire circumferential direction TC.

Note that the entire content of Japanese Patent Application No. 2013-177867 (filed on Aug. 29, 2013) is incorporated herein by reference.

As described above, the tire according to the present invention is useful because it can improve wear resistance and steering stability while suppressing a decrease in drainage performance (wet performance).

Claims

A tire including a tread portion having a tread contact surface that contacts the road surface,
The tread portion includes a plurality of circumferential grooves extending along the tire circumferential direction and a plurality of width direction grooves extending along the tire width direction on the tread ground surface.
The plurality of circumferential grooves include a main circumferential groove and a sub circumferential groove positioned on the outer side in the tire width direction with respect to the main circumferential groove,
The plurality of widthwise grooves cross the sub circumferential groove,
One end of each of the plurality of widthwise grooves communicates with the main circumferential groove,
The sub circumferential groove includes a sub circumferential groove bottom located between a pair of adjacent width direction grooves from a groove bottom position corresponding to a portion where the width groove intersects the sub circumferential groove. A tire having an inclined surface continuously inclined toward a top surface.
The tire according to claim 1, wherein the other end of each of the plurality of widthwise grooves terminates in a shoulder land portion without reaching a tread ground contact end.
The groove width of the sub circumferential groove is narrower than the groove width of the main circumferential groove, and the depth of the sub circumferential groove is shallower than the depth of the main circumferential groove in the tire radial direction. The tire according to claim 1.
The tire according to claim 3, wherein in the tire radial direction, the depth of the sub circumferential groove is 40% or more and 55% or less of the depth of the main circumferential groove.
The tire according to claim 3, wherein in the tire radial direction, a depth of the plurality of width direction grooves is shallower than a depth of the main circumferential direction groove.
2. The tire according to claim 1, wherein in the tire circumferential direction, a length of a top surface of the sub circumferential groove bottom is equal to a length of the inclined surface.
The pattern formed by the grooves provided in the tread portion is asymmetric with respect to the tire equator line,
2. The tire according to claim 1, wherein the sub-circumferential groove is located on an outer side of the vehicle with respect to the tire equator line in a state where the tire is mounted on the vehicle.