KR102377656B1 - Pneumatic tire - Google Patents

Abstract

An object of the present invention is to provide a pneumatic tire in which wet performance, abrasion resistance performance, and steering stability performance are improved in a well-balanced manner.
A first main groove 11 continuously extending in the tire circumferential direction is formed in the inner tread portion 5 . The first main groove 11 is formed at a position spaced apart from the tire equator C by a distance in the tire axial direction of 0.20 to 0.70 times the width of the inner tread 5 . The outer tread portion 6 has a plurality of slots 25 in which the groove edge 26 is not connected to either the tire equator C and the outer tread end Te2, and the tire circumference along the outer tread end Te2. A shoulder land portion 24 continuous in the direction is formed.

Description

pneumatic tire {PNEUMATIC TIRE}

The present invention relates to a pneumatic tire in which wet performance, abrasion resistance performance and steering stability are improved in a good balance.

For example, in Patent Document 1 below, a pneumatic tire used in combination for road running and circuit running is proposed. In the pneumatic tire, an inclined groove connected to the outer tread end or the tire equator is formed in the outer tread portion between the tire equator and the outer tread end in order to ensure wet performance during road driving.

However, such an inclined groove may decrease the rigidity of the outer tread portion and further deteriorate the abrasion resistance performance and steering stability. For this reason, the pneumatic tire of patent document 1 had room for further improvement with respect to the improvement of wet performance, abrasion resistance performance, and handling stability.

[Patent Document 1] Japanese Patent Laid-Open No. 2004-338628

The present invention was devised in view of the above problems, and based on improving the arrangement of the main groove formed on the inner tread and the arrangement of the slots formed on the outer tread, wet performance, abrasion resistance performance and steering stability Its main object is to provide a pneumatic tire with improved balance.

The present invention is a pneumatic tire having a tread portion having an inner tread end and an outer tread end defined by a mounting direction specified for a vehicle, wherein the tread portion includes an inner tread portion between the tire equator and the inner tread end, the tire equator and the an outer tread portion between the ends of the outer tread, wherein a first main groove continuously extending in the circumferential direction of the tire is formed in the inner tread portion, the first main groove being 0.20 times to 0.20 times the width of the inner tread from the equator of the tire a plurality of slots formed at positions spaced apart from each other by 0.70 times the distance in the tire axial direction, in the outer tread portion, along the outer tread end, the groove edge is not connected to either the tire equator or the outer tread end; It is characterized in that a shoulder land portion continuous in the tire circumferential direction is formed.

In the pneumatic tire of the present invention, it is preferable that a second main groove continuously extending in the circumferential direction of the tire is formed between the tire equator and the first main groove in the inner tread portion.

In the pneumatic tire of this invention, it is preferable that only the said slot is formed in the said outer tread part.

In the pneumatic tire of the present invention, the slot preferably includes an elliptical one whose longitudinal direction extends at an angle of 0° to 45° with respect to the tire axial direction.

In the pneumatic tire of the present invention, in the inner tread portion, a second main groove continuously extending in the tire circumferential direction between the tire equator and the first main groove, and a first land portion between the inner tread end and the first main groove and a second land portion between the tire equator and the second main groove and a third land portion between the first main groove and the second main groove are formed, in a meridian cross section including a tire rotation shaft, the first land portion , the second land portion and the third land portion each having a chamfered portion obliquely continuous with respect to the tread surface at a corner portion between the tread surface and the groove wall surface of the first main groove or the second main groove desirable.

In the pneumatic tire of the present invention, it is preferable that the first land portion, the second land portion, and the third land portion are each of a slick type in which neither a groove nor a sipe is formed.

In the pneumatic tire of the present invention, it is preferable that an angle of the first land portion and the second land portion with respect to the tire radial direction of the chamfer is larger than an angle of the third land portion with respect to the tire radial direction of the chamfer. Do.

In the pneumatic tire of the present invention, an angle of the first land portion and the second land portion with respect to the tire radial direction of the chamfer is 60° to 75°, and the third land portion in the tire radial direction of the chamfer portion The angle to is preferably 45° to 55°.

In the pneumatic tire of the present invention, it is preferable that the slot consists only of a transverse slot extending along the tire axial direction.

In the pneumatic tire of the present invention, it is preferable that the slots include a transverse slot extending along the tire axial direction and an inclined slot extending obliquely with respect to the tire axial direction, these being alternately arranged in the tire circumferential direction. .

A first main groove continuously extending in the tire circumferential direction is formed in the inner tread portion of the pneumatic tire of the present invention. The first main groove is formed at a position spaced apart from the tire equator by a distance in the tire axial direction of 0.20 to 0.70 times the width of the inner tread. Thereby, the position of the first main groove is optimized, and the pattern rigidity in the vicinity of the tire equator and the pattern rigidity in the vicinity of the inner tread end are ensured in a good balance. Accordingly, excellent wear resistance performance and steering stability are exhibited.

The outer tread portion is formed with a plurality of slots whose groove edges are not connected to either the tire equator or the outer tread end. These slots help to increase wet performance while maintaining the stiffness of the outer tread.

Further, the outer tread portion is formed with a shoulder land portion continuous in the tire circumferential direction along the outer tread end. Such a shoulder land portion can increase the rigidity in the vicinity of the outer tread end to which a large ground pressure acts at the time of cornering, and furthermore, excellent steering stability is exhibited.

As described above, the pneumatic tire of the present invention can improve the wet performance, the abrasion resistance performance, and the steering stability with good balance.

1 is an exploded view of a tread portion of a pneumatic tire according to an embodiment of the present invention.
FIG. 2 is an enlarged view of the inner tread of FIG. 1 .
3 is a cross-sectional view taken along line AA of FIG. 2 .
4 is an enlarged view of the outer tread of FIG. 1 .
5 is an exploded view of a tread portion of a pneumatic tire according to another embodiment of the present invention.
6 is an exploded view of a tread portion of a pneumatic tire according to another embodiment of the present invention.
7 is an exploded view of a tread portion of a pneumatic tire of a comparative example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

1 is an exploded view of the tread portion 2 of a pneumatic tire (hereinafter, simply referred to as "tire") 1 of the present embodiment. The pneumatic tire 1 of the present embodiment is used, for example, for a passenger car, and is particularly suitably used as a high-performance tire premised on use in both public road driving and circuit driving.

The tread portion 2 is provided with a tread pattern in which the mounting direction to the vehicle is specified. The mounting direction to the vehicle is indicated by characters or marks, for example, on a sidewall portion (not shown) or the like. In Fig. 1, when the tire 1 is mounted on a vehicle, the right side in Fig. 1 corresponds to the inside of the vehicle, and the left side in Fig. 1 corresponds to the outside of the vehicle.

By designating the mounting direction to the vehicle, the tread portion 2 has an inner tread end Te1 located inside the vehicle when mounted on the vehicle, and an outer tread end Te2 located outside the vehicle when mounted to the vehicle, there is.

Each of the tread ends Te1 and Te2 is rim-assembled on a regular rim (not shown), and a regular load is applied to the tire 1 in a regular state, filled with a regular internal pressure, and in a no-load state to achieve a camber angle of 0°. This is the grounding position on the outermost side of the tire in the axial direction when grounded on a flat surface.

A "regular rim" is a rim that is set for each tire in the standard system including the standard on which the tire is based, for example, "standard rim" for JATMA, "Design rim" for TRA, and "Measuring rim" for ETRTO. "am.

"Normal internal pressure" is the air pressure determined for each tire by each standard in the standard system including the standard on which the tire is based. "Maximum air pressure" for JATMA, "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA If it is the maximum value described in ETRTO, it is "INFLATION PRESSURE".

"Normal load" is the load that each standard determines for each tire in the standard system including the standard on which the tire is based. "Maximum load capacity" for JATMA, "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA The maximum value described in ", if ETRTO is "LOAD CAPACITY".

The tread portion 2 includes an inner tread portion 5 between the tire equator C and the inner tread end Te1, and an outer tread portion 6 between the tire equator C and the outer tread end Te2. contains

FIG. 2 shows an enlarged view of the inner tread 5 of FIG. 1 . As shown in FIG. 2 , a main groove 10 continuously extending in the tire circumferential direction is formed in the inner tread portion 5 . The main groove 10 of this embodiment extends linearly along the tire circumferential direction, for example. Moreover, the main groove 10 of this embodiment is extended with a fixed groove width, for example. However, the main groove 10 is not limited to this aspect, The aspect extended in a zigzag shape or a wave shape, or the aspect extended while increasing and decreasing a groove|channel width may be sufficient.

The main groove 10 includes a first main groove 11 and a second main groove 12 formed between the first main groove 11 and the tire equator (C). The first main groove 11 and the second main groove 12 effectively discharge the water film between the inner tread 5 and the road surface to the outside of the tire during wet driving, thereby exhibiting excellent wet performance.

The first main groove 11 is formed at a position separated from the tire equator C by a distance L1 in the tire axial direction. The distance L1 is 0.20 to 0.70 times the width W1 of the inner tread 5 . Thereby, the position of the 1st main groove 11 is optimized, and the pattern rigidity in the vicinity of the tire equator C and the pattern rigidity in the vicinity of the inner tread end Te1 are ensured in a good balance. Accordingly, excellent wear resistance performance and steering stability are exhibited.

In order to further exhibit the above-described effect, the distance L1 is preferably 0.35 times or more, more preferably 0.40 times or more, and preferably 0.55 times or less of the width W1 of the inner tread portion 5. , more preferably 0.50 times or less.

The 2nd main groove 12 is formed in the position which separated the distance L2 of the tire axial direction from the tire equator C, for example. The distance L2 is, for example, preferably 0.10 to 0.20 times the width W1 of the inner tread 5 . This second main groove 12 helps to increase the wet performance while maintaining the pattern rigidity in the vicinity of the tire equator C.

In order to make wet performance and abrasion resistance compatible, it is preferable that the groove width W3 of each main groove 10 is 9.0 mm - 15.0 mm, for example. The groove depth of each main groove 10 is, for example, preferably 5.0 mm to 6.0 mm. However, the groove width W3 and the groove depth of each main groove 10 are not limited to these ranges.

In this embodiment, the 1st main groove 11 and the 2nd main groove 12 mentioned above are formed in the inner tread part 5, The 1st land part 16, the 2nd land part 17, and the 3rd The land portion 18 is separated. The first land portion 16 is formed between the inner tread end Te1 and the first main groove 11 . The second land portion 17 is formed between the tire equator C and the second main groove 12 . The third land portion 18 is formed between the first main groove 11 and the second main groove 12 .

Each of the first land portion 16, the second land portion 17, and the third land portion 18 is preferably of a slick type in which neither a groove nor a sipe is formed. Each of these land portions 16 , 17 , 18 can increase the rigidity of the inner tread portion 5 to effectively increase the wear resistance performance and the steering stability.

3 is a cross-sectional view taken along line A-A of FIG. 2 . Meanwhile, FIG. 3 is a view illustrating a cross section of a meridian including a tire rotation shaft. As shown in FIG. 3, the 1st land part 16, the 2nd land part 17, and the 3rd land part 18 of this embodiment, respectively, the tread surface 2s and the 1st main groove 11 ) or it is preferable to have the chamfered part 20 diagonally continuous with respect to the tread surface 2s in the corner part 19 between the groove wall surfaces 13 of the 2nd main groove 12. As shown in FIG. Such a chamfer 20 is helpful in suppressing the uneven abrasion of the end edge of each land part.

The angle θ1 of the chamfer 20a of the first land portion 16 with respect to the radial direction of the tire and the angle θ2 of the chamfer 20b of the second land portion 17 with respect to the radial direction of the tire are, For example, it is preferable that the angle θ3 of the chamfered portion 20c of the third land portion 18 with respect to the radial direction of the tire is greater than 3 . Thereby, the rigidity of the 3rd land part 18 between the main grooves 11 and 12 becomes high, and the rigidity difference of each land part becomes small. Thereby, since each land part is worn uniformly, abrasion resistance performance becomes high.

The angle θ1 of the chamfered portion 20a of the first land portion 16 and the angle θ2 of the chamfered portion 20b of the second land portion 17 are preferably 60° or more, more Preferably it is 65 degrees or more, Preferably it is 75 degrees or less, More preferably, it is 70 degrees or less. These chamfers 20a and 20b are helpful in improving wet performance while suppressing uneven abrasion at the edge of each land portion.

The angle θ3 of the chamfered portion 20c of the third land portion 18 is preferably 45° or more, more preferably 48° or more, preferably 55° or less, more preferably 52° or more. is below. The chamfered portion 20c maintains the rigidity of the third land portion 18, and further reduces the difference in stiffness between the first land portion 16 and the second land portion 17 and the third land portion 18. can be made small

4 shows an enlarged view of the outer tread 6 . As shown in FIG. 4 , a plurality of slots 25 are formed in the outer tread portion 6 . In the slot 25, the groove edge 26 is not connected to either the tire equator C or the outer tread end Te2. These slots 25 help to increase the wet performance while maintaining the rigidity of the outer tread 6 .

By the arrangement of the slots 25 as described above, the shoulder land portion 24 is formed in the outer tread portion 6 along the outer tread end Te2 in the circumferential direction of the tire. Such a shoulder land portion 24 can increase the rigidity of the vicinity of the outer tread end Te2 to which a large ground pressure acts at the time of cornering, and furthermore, excellent steering stability is exhibited.

In order to further exhibit the above-described effect, the width W4 of the shoulder land portion 24 is preferably 0.15 times or more, more preferably 0.18 times or more, the width W2 of the outer tread end Te2, Preferably it is 0.25 times or less, More preferably, it is 0.22 times or less. On the other hand, the width W4 of the shoulder land portion 24 means the distance from the groove edge 26 of the slot 25 formed on the outermost tread end Te2 side to the outer tread end Te2.

The slot 25 preferably comprises, for example, an elliptical one. The slot 25 preferably extends, for example, in its longitudinal direction at an angle θ4 (not shown) of 0° to 45° with respect to the tire axial direction. Moreover, as a preferable aspect, the slot 25 of this embodiment is formed only with the transverse slot 27 extended along the tire axial direction. This arrangement of the slots 25 maintains the rigidity of the outer tread portion 6 in the tire axial direction, and furthermore, it is possible to obtain excellent steering stability.

In the present embodiment, a plurality of transverse slot pairs 30 in which two transverse slots 27 are arranged in a line in the tire axial direction are formed in the tire circumferential direction. In addition, one transverse slot 27 is formed between the pair of transverse slots 30 and 30 adjacent in the tire circumferential direction. Moreover, it is preferable that this transverse slot 27 is formed in the center part of the tire axial direction of the outer tread part 6, for example. This arrangement of the transverse slots 27 can improve the wet performance and, moreover, improve the heat dissipation properties of the outer tread portion 6 .

Moreover, as a preferable aspect, in the outer tread part 6 of this embodiment, only the slot 25 is formed, and the other groove|channel is not formed. In such an outer tread portion 6, a decrease in rigidity due to other grooves is suppressed, and excellent wear resistance performance and steering stability can be exhibited.

5 and 6, respectively, the developed view of the tread part 2 of the pneumatic tire of another embodiment of this invention is shown. In Figs. 5 and 6, the same reference numerals are attached to the components common to the above-described embodiment.

In the embodiment shown in Fig. 5, the slots 25 arranged in the outer tread portion 6 are formed only by the longitudinal slots 28 extending along the tire circumferential direction. Since the vertical slot 28 discharges water in the slot along the tire circumferential direction during wet driving, it is possible to provide high drainage properties compared to the above-described horizontal slot.

In the embodiment shown in FIG. 6 , the slots 25 arranged in the outer tread portion 6 include a transverse slot 27 extending along the tire axial direction and an inclined slot 29 extending obliquely with respect to the tire axial direction. ) is included. This inclined slot 29 helps to increase the wet performance while maintaining the rigidity of the outer tread 6 .

It is preferable that the transverse slots 27 and the inclined slots 29 are alternately arranged in the tire circumferential direction. Moreover, as a preferable aspect, in this embodiment, the horizontal slot pair 30 in which two horizontal slots 27 lined up in the tire axial direction, and the inclined slot 29 are formed alternately in the tire circumferential direction. Such an arrangement of the slots 25 can minimize a decrease in the stiffness of the outer tread portion 6 in the tire axial direction due to the inclined slots 29, and the wet performance and steering stability are improved in a well-balanced manner.

As mentioned above, although the pneumatic tire of one embodiment of the present invention has been described in detail, the present invention is not limited to the above-described specific embodiment, and may be practiced with various modifications.

[Example]

A pneumatic tire of size 205/55R16 having the basic tread pattern of any one of Figs. 1, 5 and 6 was tested based on the specifications in Table 1. As Comparative Example 1, the tire shown in Fig. 7 was tested. In the tire of Comparative Example 1, the distance from the tire equator to the first main groove was 0.78 times the width of the inner tread portion, and a slit connected to the outer tread end Te2 was formed. As Comparative Example 2, a tire having the basic tread pattern of FIG. 1 and having a distance from the tire equator to the first main groove of 0.78 times the width of the inner tread was tested. As Comparative Example 3, a tire having the basic tread pattern of Fig. 1, in which the distance from the tire equator to the first main groove was 0.15 times the width of the inner tread, and further, a tire in which the second main groove was formed on the tire equator was tested. Each test tire was tested for wet performance, abrasion resistance and handling stability. The common specifications and test methods of each test tire are as follows.

Rim: 16×7.0 JJ

Tire pressure: 200 kPa

<Wet performance>

An inside drum tester was used, and the rate of occurrence of the hydroplaning phenomenon when each test tire ran on a drum surface having a depth of 5.0 mm under the following conditions was measured. The result is an index with Comparative Example 1 being 100, and the larger the numerical value, the higher the generation rate and the better the wet performance.

Slip angle: 1.0°

Longitudinal load: 4.2 kN

<Abrasion resistance performance>

After driving the test vehicle for a certain distance, the difference between the wear amount of the land portion at the equator of the tire and the amount of wear of the land portion at the outer tread end was measured. The result is an index with Comparative Example 1 being 100, and the smaller the numerical value, the more uniform the amount of wear at the tire equator and the outer tread end, indicating that the anti-uniform wear performance is excellent.

<Steering Stability>

The steering stability when the FR vehicle having a displacement of 2000 cc in which the test tires were mounted on all wheels was run on an asphalt circling course was evaluated by the driver's sensuality. A result is a rating which makes Comparative Example 1 100, and it shows that it is excellent in handling stability, so that a numerical value is large.

The test results are shown in Table 1.

As a result of the test, it was confirmed that the wet performance, the abrasion resistance performance, and the steering stability of the pneumatic tire of the Example were improved in a good balance.

2: tread part 5: inner tread part
6: Outer tread part 11: First main groove
24: shoulder land part 25: slot
26: groove edge Te1: inner tread end
Te2: outer tread end

Claims (10)

A pneumatic tire having a tread portion in which an inner tread end and an outer tread end are determined by designating a mounting direction for a vehicle, the pneumatic tire comprising:
The tread portion includes an inner tread portion between the tire equator and the inner tread end, and an outer tread portion between the tire equator and the outer tread end,
A first main groove continuously extending in the tire circumferential direction and a second main groove continuously extending in the tire circumferential direction between the tire equator and the first main groove are formed in the inner tread portion;
The first main groove is formed at a position spaced apart from the tire equator by a distance in the tire axial direction of 0.20 to 0.70 times the width of the inner tread,
A plurality of slots whose groove edges are not connected to either the tire equator or the outer tread end are formed in the outer tread portion, and a shoulder land portion continuous in the tire circumferential direction along the outer tread end is formed;
A third land portion between the first main groove and the second main groove is formed in the inner tread portion,
The third land portion is of a slick type in which neither groove nor sipe is formed. The pneumatic tire according to claim 1, wherein only the slot is formed in the outer tread portion. The pneumatic tire according to claim 1 or 2, wherein the slot includes an elliptical one whose longitudinal direction extends at an angle of 0° to 45° with respect to the tire axial direction. The method according to claim 1 or 2, wherein a first land portion between the inner tread end and the first main groove and a second land portion between the tire equator and the second main groove are formed in the inner tread portion,
In a meridian cross section including a tire rotation axis,
The first land portion, the second land portion and the third land portion are, respectively, at a corner portion between a tread surface and a groove wall surface of the first main groove or the second main groove, obliquely continuous with respect to the tread surface A pneumatic tire with a chamfer. The pneumatic tire according to claim 4, wherein the first land portion and the second land portion are each of a slick type in which neither a groove nor a sipe is formed. 5. The pneumatic tire according to claim 4, wherein an angle of the first land portion and the second land portion with respect to the tire radial direction of the chamfer is greater than an angle of the chamfered portion with respect to the tire radial direction of the third land portion. 7. The method according to claim 6, wherein an angle of the first land portion and the second land portion with respect to the tire radial direction of the chamfer is 60° to 75°,
An angle of the third land portion with respect to the tire radial direction of the chamfer is 45° to 55°. The pneumatic tire according to claim 1 or 2, wherein the slot consists only of a transverse slot extending along the tire axial direction. A pneumatic tire having a tread portion in which an inner tread end and an outer tread end are determined by designating a mounting direction for a vehicle, the pneumatic tire comprising:
The tread portion includes an inner tread portion between the tire equator and the inner tread end, and an outer tread portion between the tire equator and the outer tread end,
A first main groove continuously extending in the tire circumferential direction and a second main groove continuously extending in the tire circumferential direction between the tire equator and the first main groove are formed in the inner tread portion;
The first main groove is formed at a position spaced apart from the tire equator by a distance in the tire axial direction of 0.20 to 0.70 times the width of the inner tread,
A plurality of slots whose groove edges are not connected to either the tire equator or the outer tread end are formed in the outer tread portion, and a shoulder land portion continuous in the tire circumferential direction along the outer tread end is formed;
The slot includes a transverse slot extending along a tire axial direction and an oblique slot extending obliquely with respect to the tire axial direction, the pneumatic tire being alternately arranged in the tire circumferential direction.
delete

Images