JP3349393B2 - Pneumatic tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire capable of exhibiting excellent wet performance and traction performance, and is preferably mounted on a high-output vehicle such as a racing car running on a circuit, for example, to improve a lap time. The present invention relates to a pneumatic tire capable of achieving the following.

[0002]

2. Description of the Related Art Tires mounted on high-output vehicles such as racing cars and sports cars running on a circuit, for example, have a primary mission of reducing lap time. The traction performance can be cited as a performance affecting the traction performance. In particular, on a wet road surface, the difference in traction performance of the tires is large, and often appears as a difference in lap time.

Conventionally, as shown in FIG. 4, a tire running on a wet road surface is generally provided with a plurality of circumferential grooves b extending linearly and continuously in the tire circumferential direction on a tread surface a. I have. However, since such a tire has a non-contact portion of the groove width area of the circumferential groove b times the number of grooves, the tire contact pressure distribution during tire rotation is always non-uniform in the tire width direction. Needless to say, the non-uniformity of the contact pressure is used to ensure drainage.However, such tires have a large reduction in traction performance, and provide satisfactory high-speed running performance on wet road surfaces. Can not do.

[0004] The present invention has been devised in view of the above problems, and has as its object to provide a pneumatic tire excellent in high-speed running performance that can achieve both wet performance and traction performance.

[0005]

According to the first aspect of the present invention,
On the tread surface, extend from one tread contact end side to the tire equator C and 10 to 30 ° with respect to the tire circumferential direction.
A first steeply inclined groove inclined from the other tread contact end side toward the tire equator C and at an angle θ2 of 10 to 30 ° with respect to the tire circumferential direction, and the first steeply inclined groove. A second steeply inclined groove that forms a substantially “C” shape with the first steeply inclined groove by inclining in the opposite direction to the tire circumferential direction from one tread contact end to the other tread contact end. The pneumatic tire is characterized in that a gentle inclined groove communicating with the first and second steeply inclined grooves is provided by extending continuously at an angle θ3 of 60 to 80 °.

According to a second aspect of the present invention, the first steeply inclined groove, the second steeply inclined groove, and the gentlely inclined groove all extend in a straight line. It is a tire containing.

Further, the invention according to claim 3 is characterized in that the first,
In the second steeply inclined groove, the first and second steeply inclined grooves having the same circumferential pitch and substantially the same phase, or the "C" -shaped center where the virtual extension thereof intersects, are displaced from the tire equator. The pneumatic tire according to claim 1 or 2, wherein:

Further, the invention according to claim 4 is characterized in that the first,
The second steeply sloping groove has a discontinuity that is interrupted in a tread contact surface, and the first and second steeply sloping grooves are alternately arranged in the tire circumferential direction. 3. The pneumatic tire according to any one of 3.

Further, the invention according to claim 5 is characterized in that the first,
The second steeply inclined groove has a discontinuous end located at the gentlely inclined groove and communicates therewith.
2. The pneumatic tire according to 1.

According to a sixth aspect of the present invention, when the tire is mounted on a four-wheeled vehicle and the tread surface of the tire is viewed from above the four-wheeled vehicle, the “C” shape is directed toward the rear of the vehicle. The pneumatic pump according to any one of claims 1 to 5, wherein a rotation direction is specified so that the gently inclined groove is inclined from the inside of the vehicle toward the outside of the vehicle toward the rear of the vehicle. Tires.

[0011] In the present specification, the term "tread contact end" refers to a contact rim assembled with a tire on a regular rim, filled with a regular internal pressure, and contacted with a regular load at a camber angle of -0 °. The circumferential position passes through the outermost end of the ground in the tire axial direction. The “tread contact width” is a distance between the tread contact ends in the tire axial direction.

The above-mentioned "regular rim" is defined as "JATM".
A standard rim specified in A, "Design Ri specified in TRA
m "or" Measuring Rim "as defined by ETRTO
The “regular internal pressure” is the maximum air pressure specified by JATMA, and the table “TIRE LOAD LIMITS AT VARI” in TRA.
OUS COLD INFLATION PRESSURES "or the maximum value specified in ETRTO" INFLATION PRESSURE ", and the" regular load "is the maximum load capacity specified in JATMA, the maximum value described in the above table of TRA, Or E
"LOAD CAPACITY" defined by TRTO. Furthermore, in the case where there is no standard such as racing tires, the normal rim, normal internal pressure, and normal load are all in accordance with the rim, internal pressure, load, etc. recommended for the tire. It can be determined individually according to the above.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a pneumatic tire according to the present invention.
As shown in FIG. 3, a first steeply inclined groove 3 extending from one tread contact end E1 toward the tire equator C, and a tread extending from the other tread contact end E2 toward the tire equator C. A second steeply inclined groove 4 inclined in a direction opposite to that of the first steeply inclined groove 3, and the first and second steeply inclined grooves by extending from one tread contact end E1 to the other tread contact end E2. It is characterized in that a gently inclined groove 5 communicating with 3, 4 is provided. Such a pneumatic tire is, for example, for a four-wheeled vehicle, more preferably a racing car,
The present invention can be implemented as a pneumatic tire for a high-output four-wheeled vehicle such as a sports car, but can also be implemented as a tire for a general passenger car.

As shown in FIG. 2, the pneumatic tire according to the present embodiment is mounted on a four-wheeled vehicle M, and the tread surface 2 of the tire is viewed from above (above) the four-wheeled vehicle. "C" formed by the first and second steeply inclined grooves 3, 4
The figure shows an example in which the rotation direction is specified so that the character shape expands toward the rear of the vehicle and the gentle slope groove 5 tilts rearward from the inside of the vehicle toward the outside of the vehicle.

In the tire shown in FIG. 1, the rotation direction can be determined in the direction of arrow Ro, and the tread contact end E
Reference numeral 1 denotes a vehicle mounted on a four-wheeled vehicle with the tread contact edge E2 facing the outside of the vehicle and the tread contact end E2 facing the inside of the vehicle. Regarding the arrangement of the tires, the front wheels and the rear wheels are the same. As described above, the present embodiment also shows a pneumatic tire arrangement structure for a four-wheeled vehicle.

In the pneumatic tire of this embodiment, as shown in FIG. 1, the first steeply inclined groove 3 extends straight from one tread contact edge E1 toward the tire equator C and extends in the tire circumferential direction. And the second steeply inclined groove 4 extends straight from the other tread contact edge E2 toward the tire equator C and extends 10 to 30 ° with respect to the tire circumferential direction. By inclining at an angle θ2 and in a direction opposite to the direction of the first steeply inclined groove 3, a substantially “C” shape is formed with the first steeply inclined groove.

The first and second steeply inclined grooves 3 and 4 having the "C" shape are sequentially grounded from the center of the tread surface 2 to the tread ground end by the rotation of the tire. In order to move, the water film at the center of the tread surface 2 is effectively passed through the first and second steeply inclined grooves 3, 4, and the tread grounding end E1,
By leading to the E2 side, the wet performance is improved.

The reason why the inclination angles θ1 and θ2 of the first and second steeply inclined grooves 3 and 4 with respect to the tire circumferential direction are limited is that if the angles θ1 and θ2 are less than 10 °, each of the steeply inclined grooves 3 and 4 is steep. This is because the action of the inclined grooves 3 and 4 is substantially the same as that of a conventional circumferential groove along the tire circumferential direction, resulting in uneven contact pressure and impairing traction performance. When the angles θ1 and θ2 exceed 30 °,
This is because the inclination of the groove increases, so that drainage resistance increases and improvement in wet performance cannot be expected.

For these reasons, the inclination angles θ1, θ2 of the first and second steeply inclined grooves 3, 4 with respect to the tire circumferential direction.
2 is 10 to 30 °, more preferably 15 °.
It is desirably set to ２５25 °. Also, the inclination angle θ
1 and θ2 may be the same angle or may be different, but from the viewpoint of securing the rigidity of the block of the tread surface 2, the intersection angle is the angle between the first and second steeply inclined grooves 3, 4. Preferably, the angle is at least 30 °. The pneumatic tire according to the present embodiment has the same angle θ1 and θ2. And the angle θ
1, θ2 is set to 20 °.

In the present embodiment, the first steeply inclined groove 3 is located in the vicinity of the tread contact end slightly spaced inward in the tire axial direction from one tread tread end E1, which is the tread tread end facing the vehicle outside. And the tire equator C
And has a break 3a that breaks without reaching the other tread contact end E2 facing the vehicle inside. The distance t is desirably set to, for example, 10% or less of the tread contact width TW in order to maintain drainage from the tread contact end E1 through the first steep groove 3. It is also preferable that the first steeply inclined groove 3 reaches the tread contact edge E1 at t = 0.

The discontinuous end 3a of the first steeply inclined groove 3
Exemplifies one that is communicated with the gentle inclined groove 5 and interrupted. In the present embodiment, the discontinuous end 3a terminates at a position separated from the tire equator C by a distance S1 of 5% of the tread contact width TW. The position of the break 3a is the first
Of the steeply inclined groove 3 is defined as an intersection with the groove center line of the gentlely inclined groove 5.

The second steeply inclined groove 4 extends toward the tire equator C from the other tread contact end E2, which is the tread contact end facing the inside of the vehicle in this embodiment. The second steeply inclined groove 4 exemplifies a groove having a discontinuous end 4a that is discontinued on the tread surface 2 without reaching the tire equator C.

The discontinuous end 4a of the second steeply inclined groove 4 is
As in the case of the first steeply inclined groove 3, an example in which the groove is connected to and interrupted by the gentlely inclined groove 5 is illustrated. In the present embodiment, the discontinuous end 4a has a width from the tire equator C to the tread contact width TW of 8.
It is at a position separated by a distance S2 of 5%. In addition, break 4a
Is set so that the groove center line of the second steeply inclined groove 4 is
Is defined as the point of intersection with the groove center line.

As described above, in this embodiment, each of the discontinuous ends 3a, 4a of the first and second steeply inclined grooves 3, 4 is formed as follows.
In each case, the first and second steeply inclined grooves 3 and 4 are arranged so as to be axially displaced from the tire equator C and alternately arranged in the tire circumferential direction. For this reason, the water film near the center of the tread surface 2 can be alternately discharged toward the tread grounding ends E1 and E2 through the first and second steeply inclined grooves 3 and 4, thereby further improving the wet performance. It is preferable in that it is possible.

The circumferential pitches of the first and second steeply inclined grooves 3 and 4 are set to be substantially the same when a change in pitch due to a pitch variation is allowed in this embodiment. In the present embodiment, each tread grounding end E1, E
The first and second steeply inclined grooves (for example, 3A and 4A, 3B and 4B) of substantially the same phase extending from substantially the same position in the tire circumferential direction or the "C" -shaped center H at which the virtual extension line intersects
c is deviated from the tire equator C.
In this example, the deviation is on the tread contact end E2 side located inside the vehicle.

As a result, the drainage can be effectively drained by using the first steeply inclined grooves 3 on the ground contact surface outside the tire equator where the contact pressure becomes large, for example, on the tire outside the corner ring during cornering. Can be improved in wet performance.

Next, the gently inclined groove 5 extends from one tread contact end E1 to the other tread contact end E2 at an angle θ3 of 60 to 80 ° with respect to the tire circumferential direction and continuously extends. The first and second steeply inclined grooves 3 and 4 communicate with the discontinuous ends 3a and 4a. Such a gently inclined groove 5
In the present embodiment, when viewed from above when the vehicle is mounted, it is arranged so as to always be inclined rearward from the inside of the vehicle toward the outside of the vehicle.

As a result, the edge of the gentle slope groove 5 is sequentially grounded from the inside of the vehicle to the outside of the vehicle. Therefore, during straight running on a wet road, the tread grounding end E2 inside the vehicle and the tread grounding end outside the vehicle. Since the water can be effectively drained to E1, and the gentle slope groove 5 communicates with the first and second steep slope grooves 3 and 4, the water guided through the gentle slope groove 5 further decreases. It is also possible to branch to the first steep groove 3 and drain to the tread contact end E1 side. As a result, even on a road surface having a relatively thick water film, high drainage performance is exhibited and hydroplaning generation speed and the like are improved. Can be shifted to the high-speed side. Also, the gently inclined groove 5
As a result, during cornering of the vehicle, it is possible to help discharge water in the ground contact surface of the tire outside the cornering to the outside of the vehicle, so that turning performance on a wet road can also be improved.

Further, in the present embodiment, the inclination angle θ3 of the gentle inclination groove 5 is set to 70 ° with respect to the tire circumferential direction, and the inclination direction of the gentle inclination groove 5 is the first steep direction. It is equal to that of the inclined groove 3. And, the gently inclined groove 5 is provided in the first
The block B1 having a substantially parallelogram shape can be partitioned by communicating with the steeply inclined groove 3, and the substantially rectangular block B2 can be partitioned by being substantially perpendicularly connected to the second steeply inclined groove 4.

Each of these blocks B1 and B2 shows a preferred mode in which the tire circumferential length BL is formed in a vertically long shape larger than the tire axial length BW. Such blocks B1 and B2 which are vertically long in the circumferential direction can effectively transmit traction to the road surface, particularly when traveling straight ahead, and can greatly contribute to improvement in traction performance.

On the other hand, the inclination angle θ3 of the gentle inclination groove 5 is set to 6
The reason why the angle is limited to the range of 0 to 80 ° is that the block B1 located on the vehicle outer side of the tire on which a large load acts, such as during cornering, generates a large cornering force by increasing the tire axial length BW as much as possible. . If the angle θ3 is less than 60 °, the block B
1, the length BW in the tire axial direction BW tends to be small, and a large cornering force cannot be generated. Conversely, when the angle θ3 exceeds 80 °, the edges of the gentle inclined grooves 5 are almost simultaneously formed during tire rotation. Since the ground is grounded to the road surface, the water film on the tread ground end E2 cannot be effectively guided to the tread ground end E1, and the wet performance is impaired.

The gently inclined groove 5 extends from one tread contact end E1 to the other tread contact end E1 at the angle θ3.
It is necessary to extend continuously to 2. The reason is,
If the gently inclined groove 5 is bent, for example, in a V-shape, the water inside the vehicle cannot be sufficiently drained to the outside of the vehicle at the contact surface of the tire, so that the wet performance particularly at the time of cornering is extremely reduced. It is because. In addition,
In the present embodiment, as clearly shown in FIG.
At the tread grounding end E2, a so-called tread grounding end E2
At the intersection with the second steeply inclined groove 4,
That is, the gently inclined groove 5 interrupted near the tread contact end E2.
And a gentle slope groove 5 reaching the so-called tread contact edge E2.
Are provided alternately every other line. Claim such a configuration
Item 1 “From one tread contact edge E1 to the other
Extend to the pad grounding end E2 continuously "
Is apparent from FIG.

As shown in FIG. 3, the right and left tire contact surfaces L and R during the right cornering show that the right side tire inside the cornering and the left side tire outside the cornering have the vehicle center side. Although the contact pressure decreases, the pattern blocks of these portions having a small contact pressure can be reduced by communicating the gentle slope grooves 5 with the first and second steep slope grooves 3 and 4. This increases the sea portion (non-ground portion) of the sealand ratio and helps to further improve cornering performance on wet roads.

Each of the first and second steeply inclined grooves 3, 4 and the gentlely inclined groove 5 preferably has a groove width measured on the tread surface of 6 mm or more, more preferably from the viewpoint of wet performance. Has a groove width dimension of 3 to 7%, more preferably 3 to 6% of the tread contact width. Further, the first and second steeply inclined grooves 3 may have different groove widths. For example, by making the groove width of the second steeply inclined groove 4 located inside the vehicle larger than the groove width of the first steeply inclined groove 3 located outside the vehicle, further improvement in wet performance can be expected. . Also, the first and second steeply inclined grooves 3, 4
The groove depth is, for example, 3 to 20 mm, more preferably 4 to 1 mm.
Preferably, it is 5 mm.

The pneumatic tire according to the present embodiment does not have a circumferential groove extending continuously in the tire circumferential direction as seen in a conventional tire, and all grooves are formed in the tire circumferential direction. It is inclined. Accordingly, it is possible to prevent the contact pressure in the width direction of the tread surface 2 from becoming non-uniform at all times during the rotation of the tire, so that it is possible to prevent the traction performance from being reduced.

As described in detail above, the first and second steeply inclined grooves 3, 4 and the gentlely inclined groove 5 are formed not only in a preferred embodiment extending in a straight line but also in a smooth curved line, bent line, or the like. You can also. Also, the first and second steeply inclined grooves 3, 4
In the present embodiment, the one indirectly communicating via the gentle slope groove 5 is illustrated, but the first and second steep slope grooves 3, 4
The discontinuous ends 3a and 4a may be in a substantially "V" shape by directly communicating with each other, and such a "V" shape is also included in the "C" shape referred to in the present invention. Further, the center of the "C" shape may be on the tire equator, and the pneumatic tire of the present invention is applicable to any tire having a radial structure and a bias structure.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A tire of the present invention (Example 1), a conventional tire (conventional example), and comparative tires (Comparative Examples 1 to 5) having a tire size of 210 / 650R19 are shown on a four-wheeled 2000cc domestic sports car. Wear it as shown in Fig. 2 and drive around the Fuji Speedway (approximately 4.47 km per lap) with one racing driver riding on it. Wet performance and traction performance are evaluated by the driver's sensuality using the 10-point method, and the lap time is evaluated. The average value (N = 5) of the lap times excluding the fastest and lowest times was measured. The weather during the run was rain and the temperature was 16 ° C. Table 1 shows the test results.

[0038]

[Table 1]

As a result of the test, it can be confirmed that, in the tire of the example, the traction performance and the wet performance are maintained at a high level, and the results clearly appear in the lap time.

[0040]

As described above, the pneumatic tire of the present invention has the first and second steeply inclined grooves having a "C" shape.
Slowly inclined grooves communicating with the first and second steeply inclined grooves are provided by continuously extending from one tread contact end to the other tread contact end at a predetermined angle with respect to the tire circumferential direction and communicating with the first and second steeply inclined grooves. As a result, the function of effectively draining the water of the central tread portion of the tread surface to the grounding end side and the function of draining water from one grounding end to the other grounding end can be simultaneously exhibited. It can improve both performance and performance, especially for high-power vehicles such as racing cars and sports cars, and can demonstrate excellent straight-line and turning performance at high speeds on wet roads, for example, reliably reducing lap time on the circuit be able to.

[Brief description of the drawings]

FIG. 1 is a tread pattern developed view showing an embodiment of a pneumatic tire of the present invention.

FIG. 2 is a plan view showing an arrangement structure of a pneumatic tire for a four-wheeled vehicle.

FIG. 3 is a diagram showing a ground contact surface during cornering.

FIG. 4 is a diagram illustrating a conventional pneumatic tire.

FIG. 5 is a tread pattern diagram of a conventional example.

[Explanation of symbols]

 2 Tread surface 3 First steeply inclined groove 3a End of first steeply inclined groove 4 First steeply inclined groove 4a End of second steeply inclined groove 5 Slowly inclined groove Hc C-shaped center TW Tread ground Width M four-wheeled vehicle

Claims (6)

(57) [Claims] 1. A first steeply inclined groove extending from one tread contact end side toward a tire equator C and inclined at an angle θ1 of 10 to 30 ° with respect to the tire circumferential direction, and the other tread on a tread surface. By extending from the ground contact end side to the tire equator C and inclining at an angle θ2 of 10 to 30 ° with respect to the tire circumferential direction and in a direction opposite to the first steeply inclined groove,
A second steeply inclined groove which forms a substantially "C" shape with the first steeply inclined groove; and an angle of 60 to 80 [deg.] With respect to the tire circumferential direction from one tread contact end to the other tread contact end. A pneumatic tire, wherein a gentle slope groove communicating with the first and second steep slope grooves is provided by extending continuously at an angle of θ3. 2. The pneumatic tire according to claim 1, wherein each of the first steeply inclined groove, the second steeply inclined groove, and the gentlely inclined groove extends in a straight line. 3. The first and second steeply inclined grooves, each of which has the same circumferential pitch and substantially the same phase, have a "C" -like shape in which the first and second steeply inclined grooves or virtual extension lines thereof intersect. 3. The pneumatic tire according to claim 1, wherein the center is deviated from the tire equator. 4. The first and second steeply inclined grooves have discontinuous ends that are interrupted in the tread contact surface, and the first and second steeply inclined grooves are alternately arranged in the tire circumferential direction. The pneumatic tire according to any one of claims 1 to 3, wherein: 5. The pneumatic tire according to claim 1, wherein the first and second steeply inclined grooves are communicated with the discontinuous ends thereof being positioned in the gentlely inclined grooves. . 6. When the tire is mounted on a four-wheeled vehicle and the tread surface of the tire is viewed from above the four-wheeled vehicle,
The rotation direction is specified so that the character shape expands toward the rear of the vehicle and the gentle slope groove is inclined rearward from the inside of the vehicle toward the outside of the vehicle.
6. The pneumatic tire according to any one of items 1 to 5.