JPH07246806A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To prevent a vehicle from one side flow for improving straight traveling performance and permit a pneumatic tire to be preferably employed in a passenger car by groove wall surfaces on the previous contact and subsequent contact sides of a transverse groove in the previous and subsequent contact regions having falling- down portions inclined to the normal in the respective directions of previous contact and subsequent contact of the tread surface. CONSTITUTION:A tread part 2 of a tire is supposedly divided into a previous contact region F occupying the left side of the equator line CO of the tire and a previous contact region R occupying the right side. In the previous contact side region formed between one end edge E1 and intermediate longitudinal groove 9B in the previous contact region F is provided a falling-down groove portion 3 in which a specific inclination of the previous contact side of the previous contact portion 10F of a lateral groove 10 to the normal on the previous contact side groove wall surface 16 is larger than that of the subsequent contact side groove wall surface 17. Also, in the subsequent contact region R on the subsequent contact region between the end edge E2 and intermediate longitudinal groove 9B, a groove portion 14 in which the specific inclination of the subsequently contacting region portion 10R of the lateral groove 10 to the normal on the subsequently contacting side groove wall surface 20 is larger than that of the previously contacting side groove wall surface 19 is provided.

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 improving one-sided flow of a vehicle and enhancing straight running performance.

[0002]

2. Description of the Related Art With recent improvements in vehicle performance and maintenance of road networks, tires are required to have predetermined performance when, for example, the steering wheel is released in addition to various performances such as durability, steering stability, and riding comfort. It is desirable to further improve the driving comfort by, for example, reducing the so-called one-way flow of the vehicle, which shifts to one side with respect to the straight traveling direction line while traveling the distance, reducing so-called one-way flow of the vehicle and improving straight traveling stability. ing.

Conventionally, this one-way flow of a vehicle is attributed to the so-called conicity, which is cone-shaped in the tire axial direction left and right of the tread portion, particularly due to the difference in the circumferential length of the belt layer, and therefore in the tire axial left-right direction. Various measures have been taken to increase the uniformity of the.

[0004]

However, it has been found that the improvement of the conicity cannot sufficiently prevent the one-way flow of the vehicle.

On the other hand, due to the recent progress in tire measurement technology, as schematically shown in FIG. 14, a cornering force generated in the tire axial direction Y when a small slip angle α is applied to the tire traveling direction X, That is, the lateral force Fo and the self-aligning torque SAT that rotates in the direction of the slip angle α around the vertical axis Z passing through the tire center can be measured with high accuracy.

Such a measurement result is shown with a straight line K using the self-aligning torque SAT on the horizontal axis and the lateral force Fo on the vertical axis, as shown in FIG. 15, with the camber angle β set to 0. Be done. Further, in the straight line K, black circles indicate the cases where the slip angle α is 0 degree, −0.2 degree, and +0.4 degree.

Thus, in radial tires,
Generally, the lateral force Fo and the self-aligning torque SAT are generated even in the straight traveling state. The lateral force Fo when the slip angle α and the camber angle β are both 0
Is called LFD (Lateral Fose Deviation).

Such self-aligning torque SA
In relation to T and the lateral force Fo, the lateral force Fo at the intersection point ko1 where the straight line K intersects the vertical axis, that is, the lateral force Fo when the self-aligning torque SAT does not occur is named the residual CF. It was found that this residual CF affects the one-way flow of the vehicle. That is, when the residual CF is in the positive direction, it means that the vehicle unidirectionally flows to the right. Therefore, the unidirectionality of the vehicle can be evaluated by the direction and the size of the residual CF. Therefore, in order to prevent the unidirectional flow of the vehicle, This residual CF
It is necessary to reduce

In the case of a tire having a so-called conicity, in which a difference in radius occurs between the right and left sides of the tire equator, the residual CF and the self-aligning torque SAT are ascending toward the large diameter side when the tire is assembled. When changing to the right or the left with respect to the so-called front and back sets, the straight line K is, as shown in FIG. 16, the straight line K1 of the front set and the straight line K2 of the back set, It becomes two parallel straight lines. Further, as shown in FIG. 16, the average value of the lateral force when the slip angle α is 0 and the camber angle β is 0 is called plysteer, and the deviation from each average value is the lateral force Fo.
It is defined as the community in.

Further, in the relationship between the one-way flow of the vehicle, the residual CF, and the residual self-aligning torque SAT, the total self-aligning torque SAT becomes 0 when traveling with the steering wheel released, so that When
The residual CF is generated in the tire. Normally, a force based on the community is further applied to this, and a lateral force based on the tire and a resultant force of the residual CF is generated on the vehicle with respect to the tire.

An example of the residual CF and the flow of the vehicle is shown in FIG.
Shown in. The one-way flow of this vehicle is 100m at 50km / h
Is the amount of lateral deviation that occurs when the vehicle is running with the steering wheel released, and FIG. 12 is measured using a tire of size 215SR15. Thus, it was found that the residual CF and the vehicle flow have a correlation, and it was found that it is better to reduce the residual CF in order to prevent the vehicle flow.

The present inventor has conducted various studies to reduce the residual CF on the assumption that the conicity is not more than a predetermined value. As a result, the residual CF changes depending on the tread pattern of the tire and the structure of the belt layer. I found that

Here, the effect of the belt layer on the residual CF is that the belt cord of the belt ply forming the belt layer is positioned at the outermost radial direction and the belt cord thereof is inclined with respect to the tire equator. It is known that it depends most on the orientation.

That is, as shown in FIG. 8A, when the tire is viewed from the front, when the belt cords b of the outermost belt plies are arranged so as to be inclined so that the left side in the axial direction of the tire is first-arriving (normally attached). In FIG. 8B, in which the contact surface of the tire is viewed from the inside of the tire, the rotational moment ML acting in the counterclockwise direction acts on the contact surface of the tire from the road surface. As a result, the ground contact portion of the tire causes the undulating vehicle to unidirectionally flow.

Further, as shown in FIG. 9 (A), when the belt cords b'are arranged so as to be inclined so that the right side in the tire axial direction comes first (reverse sticking), a clockwise direction is applied to the ground contact surface of the tire. The rotation moment MR acting on the tire acts on the ground contact portion of the tire as illustrated in FIG. Will flow in the opposite direction.

In order to solve the above problems, there is also a proposal (for example, Japanese Patent Laid-Open No. 60-234003) to provide a reinforcing layer on the outer side of the belt layer in the radial direction using a cord that circulates in the tire circumferential direction. However, by providing such a reinforcing layer, there is a problem that the weight of the tire increases and the fuel consumption increases.

Therefore, a block pattern corresponding to the structure of the belt layer has been proposed. For example, JP-A-63-
Japanese Patent No. 13802 proposes that the direction in which the shearing rigidity of the block is maximized is regulated so as to correspond to the direction of the cord of the outermost layer of the belt layer.
In Japanese Patent No. 416, a proposal to change the inclination angle of the lateral groove forming the block with respect to the tire axis between the central portion and the side portion of the tread portion, and further, JP-A-4-193607.
Proposals have been made to regulate the number of blocks made by the issue.

However, all of these proposals are limited to the block pattern, and the patterns are naturally regulated so that some lateral grooves widely used for passenger cars are connected in a rib shape. There is a problem that it cannot be applied to a tire having a pattern.

Particularly for passenger car tires, in recent years, there has been an increasing demand for improvement in high-speed running performance and noise reduction, and in response to these demands, the pattern is not limited to a block pattern, but a universal pattern. Even then, the emergence of tires that can improve one-sided flow of cars came to be expected.

With respect to the lateral groove formed in the tread portion, the inventor regulates the inclination of the groove wall surface forming the lateral groove in association with the inclination of the outermost belt cord of the belt layer, so that the residual layer generated by the belt layer is controlled. The inventors have found that the CF and the residual CF generated by the tread pattern cancel each other out, and can improve the one-way flow of the vehicle without being restricted by the pattern, and completed the present invention.

It is an object of the present invention to provide a pneumatic tire that improves one-way flow of a vehicle, enhances straight running performance, and can be suitably used for passenger cars.

[0022]

According to the present invention, a carcass is folded from a tread portion through a sidewall portion and around a bead core of a bead portion, and a belt cord disposed inside the tread portion and outside the carcass in the tire radial direction. A belt layer made up of a plurality of belt plies stacked at an angle with respect to the tire equator, and further provided with a plurality of vertical grooves extending in the circumferential direction in the tread portion and a lateral groove extending in a direction intersecting with the vertical grooves. In the pneumatic tire, the tread portion is a tire equatorial plane as a boundary, and the tire axial left and right, the belt cord of the outermost belt ply in the radial direction is a first-arrival region that becomes a region on the first-arrival side when rolling the tire. , And the other rear arrival area is virtually divided, and in the first arrival area, the groove wall surface on the first arrival side of the lateral groove is with respect to the normal line perpendicular to the tread surface. The tread surface inclines in a first-arriving direction and at an inclination angle θ2, and the groove wall surface on the rear-end side inclines at a tilt angle θ1 in a direction in which the tread surface arrives later with respect to the normal line, and in the rear-attachment area. Indicates that the groove wall surface on the first-arriving side of the lateral groove is inclined at an inclination angle θ3 in the direction in which the tread surface is first-arriving with respect to the normal line, and the groove wall surface on the later-arriving side has a tread surface with respect to the normal line. The lateral groove includes a tilted groove portion in which the inclination angles θ2 and θ4 are larger than the inclination angles θ1 and θ3, respectively, in the first-arrival area and the rear-arrival area, respectively. It is a pneumatic tire characterized by that.

By intersecting the vertical groove with the horizontal groove, it is possible to form a block pattern divided in the tread portion by the vertical groove and the horizontal groove.

Further, it is preferable that the belt cords of the outermost belt ply in the radial direction are arranged at an angle of 16 to 26 degrees with respect to the tire equator.

[0025]

With the above construction, when the tread portion comes into contact with the ground while the tire is running, the rotational moment generated by the cord of the belt ply radially outermost of the belt layer tilting with respect to the tire equator is prevented. Since the lateral groove of the part is canceled by the rotational moment generated by the difference in the inclination of the groove wall surface due to the difference in the inclination angle of the groove wall surface between the first-arriving area and the second-arriving area, the residual CF of the entire tire can be brought close to zero. I can. As a result, the one-way flow of the vehicle is reduced, and straight running performance can be improved.

In the present invention, as described above, since the front and rear sides of the lateral groove include the tilted groove portions in which the relative inclination angles of the groove wall surfaces facing each other are regulated,
The tread pattern is not limited to a block pattern, but is used for tires with a wider pattern than conventional ones, such as those that are partially connected in a rib shape and that have lug grooves partially. Therefore, it can be suitably used for passenger car tires aiming at high speed and high performance.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings by taking a case where a pneumatic tire is a radial tire for passenger cars as an example.

1 to 4, the pneumatic tire 1 is
The tread portion 2 and a sidewall portion 3 extending from both ends thereof inward in the radial direction of the tire, and the sidewall portion 3
And a bead portion 4 located at the inner end in the tire radial direction.

Further, in the pneumatic tire 1, a carcass 6 is formed by folding the bead core 5 of the bead portion 4 from the tread portion 2 through the sidewall portion 3 toward the outer side in the tire axial direction, and inside the tread portion 2. A belt layer 7 arranged on the outer side in the radial direction of the carcass 6.

The carcass 6 is a semi-radial or radial direction array in which the carcass cords are arranged at an angle of 45 to 90 degrees with respect to the tire equator CO, and as the carcass cords, fiber cords such as nylon, polyester and rayon are used. In addition, steel cord is adopted.

The belt layers 7 are arranged in the first radial direction outward from the carcass 6, that is, toward the outer surface of the tread portion 2.
The belt ply 7A and the second belt ply 7B are arranged in this order. In the first belt ply 7A, for example, the cords 12 are arranged so as to be inclined to the upper right with respect to the tire equator CO in the range of 16 degrees to 26 degrees, while the second belt ply 7B is arranged in the first belt ply 7A.
Contrary to A, they are arranged so as to be inclined to the upper left in the range γ of 16 ° to 26 °, and are formed as so-called normal bonding. Therefore, the first and second belt plies 7A and 7B have cords 1
When the two cross each other, a hoop effect is generated by both plies 7A and 7B, and the rigidity of the tread portion 2 in the circumferential direction and the axial direction can be increased. In this embodiment, the second belt ply 7B is formed as the outermost belt ply 11.

The inclination angle γ of the belt cord 12
Is less than 16 degrees, the shape of the ground contact surface becomes a flat shape that expands in the tire axial direction when the tire is running.
If it becomes larger than the degree, the contact surface shape becomes a circular shape with a narrow width in the tire axial direction, and the contact property between the central portion and the shoulder portion of the tread surface 2A is changed and the balance of each is lost, which is not preferable.

The first and second belt plies 7A and 7B
Each of the belt cords 11 includes steel cords, fiber cords such as nylon, polyester, and rayon having a relatively high elastic modulus, as well as Teflon and aromatic polyamide fibers.

As described above, in the belt layer 7, the belt cord 12 of the outermost belt ply 11 is tilted to the right in FIG. 3, so that the belt cord 12 on the left side in the tire axial direction in FIG. Therefore, in this embodiment, the tread portion 2 is virtually divided into a first-arrival area F that occupies the left side of the tire equator CO and a last-arrival area R that occupies the right side of the tire equator CO.

Further, in the tread portion 2, a plurality of vertical grooves 9A, 9A, 9B, which extend in a substantially straight line in the circumferential direction, are six in this example.
9B, 9C, 9C (referred to as vertical groove 9 when collectively referred to)
Are arranged at symmetrical positions with the tire equator CO interposed therebetween.

Further, in the tread portion 2, a plurality of lateral grooves 10 arranged so as to intersect these vertical grooves 9 ... Cross the tire equator CO from one edge E1 of the tread portion and the other edge E.
2 and S at the intersection with the tire equator CO so that the intersection angle with the tire equator CO becomes the smallest.
It is bent and formed in a letter shape. Therefore, the tread portion 2 is formed with a block pattern composed of these vertical grooves 9, ..., Horizontal grooves 10 and blocks surrounded by the end edges E1, E2, and the horizontal grooves 10 are formed in the first-arrival area portion 10F and the last-arrival area. It is divided into a portion 10R.

In the first-arrival region portion 10F of the lateral groove 10 in the first-arrival region F, as shown in FIG. 4A, the groove wall surface 16 on the first-arrival side has the tread surface 2 with respect to the normal line N perpendicular to the tread surface 2A. Tilts in the direction f that arrives first at the tilt angle θ2,
Further, the groove wall surface 17 on the rearward-attaching side is inclined with respect to the normal line N in the rearward-arriving direction r at an inclination angle θ1.

On the other hand, in the rear-arriving region R, in the rear-arriving region portion 10R of the lateral groove 10, as shown in FIG. 4B, the groove wall surface 19 on the first-arriving side has the tread surface 2 with respect to the normal line N. The groove wall surface 20 on the trailing side is tilted at the tilt angle θ3 in the first-arriving direction f, and at the tilt angle θ4 in the trailing-direction r with respect to the normal line N. Moreover, each of these inclination angles θ1,
All of θ2, θ3, and θ4 are set in the range of 5 to 20 °.

In this embodiment, in the first-arrival area F, the first-arrival side area FE formed between the one edge E1 and the intermediate vertical groove 9B is located on the first-arrival side of the first-arrival area 10F of the lateral groove 10. The tilted groove portion 13 is provided in which the inclination angle θ2 of the groove wall surface 16 is larger than the inclination angle θ1 of the groove wall surface 17 on the rear side.

On the other hand, in the post-arrival region R, in the post-adhesion side region RE formed between the other edge E2 and the intermediate longitudinal groove 9B, in the post-adhesion region portion RE of the lateral groove 10, the post-adhesion of the lateral groove 10 is obtained. The inclination angle θ4 of the groove wall surface 20 on the rearward-mounting side of the region portion 10F is the inclination angle θ of the groove wall surface 19 on the first-arriving side.
A fall groove portion 14 larger than 3 is provided.

In the tilted portions 13 and 14, if the tilt angles θ1 and θ3 are less than 5 degrees, the groove wall surfaces 17 and 19 are formed.
Rigidity at the edge portion that intersects the tread surface 2A decreases, and uneven wear such as heel and toe wear easily occurs.
If the tilt angles θ2 and θ4 are larger than 20 degrees, the groove cross-sectional area becomes small, and the drainage performance is reduced, so that there is a risk that the steering stability on the wet road surface is reduced.

In the tilt groove portions 13 and 14, the inclination angle differences (θ2-θ1) and (θ4-θ3) are set within the range of 5 degrees or more and 15 degrees or less.

In this embodiment, the falling groove portions 13 and 14 are
The lateral groove 10 in the portion other than the above is formed as a groove having a symmetrical groove cross section in which the inclination angles θ1, θ2, θ3, and θ4 of the wall surface of the groove are substantially the same.

FIGS. 5 and 6 show a mode in which the belt cord 12 of the outermost belt ply 11 is arranged so as to be inclined upward in the range of 16 to 26 degrees, that is, is formed as so-called reverse attachment.

In this example, the outermost belt ply 11 is
The belt cord 12 of FIG. 5 is inclined to the upper right in FIG. 5, so that the right side in FIG. 3 is the first belt belt 12 compared to the left side. In this embodiment, the first tread portion 2 occupies the right side from the tire equator CO. It is virtually divided into a region F and a rear arrival region R occupying the left side of the tire equator CO.

Therefore, in this example, the falling groove portions 13 and 14 are
In between, the groove cross-sectional shape of the lateral groove 10 is, as shown in FIG. 6, a shape that is inclined leftward and rightward with respect to the tire axial direction of that in FIGS.

The belt cord 12 of the outermost belt ply 11 of the belt layer 7 shown in FIGS.
That is, at the time of normal attachment, the belt cord 11 is arranged as shown in FIG.

In FIG. 8B in which the ground contact surface of the tread surface 2A in this normal attachment is viewed from the inside of the tire, when the tire 1 rotates clockwise due to the inclination of the belt cord 12, it rotates counterclockwise. The rotational moment ML acting in the direction of the arrow acts on the ground contact surface of the tire, and the rotational moment ML causes the ground contact portion of the tire to wavy and deform, which causes one-way flow of the vehicle.

On the other hand, in the tread pattern, in the lateral groove 10, the inclination angles θ1, θ2, θ3, θ4 of the groove wall surfaces in the falling groove portion 13 of the first-arrival area F and the rear-arrival area R are shown in FIG. ) And (B), the rotational moment (-ml) acting in the clockwise direction acts due to the configuration shown in FIG.

Therefore, on the ground contact surface of the tire, the rotational moment ML caused by the inclination of the belt cord 12 and the rotational moment (-ml) caused by the tread pattern act so as to cancel each other and approach zero. Overall, the rotation moment at the contact surface will be significantly reduced.

Further, as shown in FIGS. 5 and 6, when the belt cord 12 of the outermost belt ply 11 rises to the right, that is, when the belt cord 12 is reversely attached, the belt cord is arranged as shown in FIG. 9 (A).

In FIG. 9B in which the ground contact surface of the tread surface 2A in this reverse attachment is viewed from the inside of the tire, when the tire 1 rotates clockwise, the rotational moment MR acting in the clockwise direction acts on the contact of the tire. The rotation moment MR acts on the ground and causes the vehicle to unidirectionally flow in a direction opposite to that of the above-mentioned tire which is normally attached.

In the tread pattern, the lateral groove 10
As shown in FIG. 6, the groove wall inclination angles θ1, θ2, θ3, and θ4 are arranged symmetrically with respect to the tire with the normal attachment shown in FIG. 4 around the tire equator CO. The rotational moment (-mr) that acts on is applied.

As a result, the rotation moment MR and the rotation moment (-mr) cancel each other out, and the rotation moment of the ground contact surface can be reduced as in the case of the normal attachment.

As described above, the lateral groove 10 formed on the tread surface 2A corresponding to the normal attachment and the reverse attachment of the belt layer 7 has the groove wall surfaces facing the first-arriving area F and the last-arriving area R of the belt cord 12, respectively. By providing a pair of tilt groove portions 13 and 14 whose inclinations are opposite to each other, a rotational moment in the opposite direction which can cancel the rotational moment caused by the inclination of the belt cord 12 is generated, The rotational moment generated on the tread surface 2A is 0
It is possible to suppress the one-sided flow of the vehicle that occurs when the vehicles cancel each other so that they approach each other and to improve the stability of the traveling.

FIG. 7 shows a lateral groove 1 having a symmetrical mountain shape centering on the tire equator CO and heading toward the tread edges E1 and E2, respectively.
Another mode in which 0 is provided is shown. In FIG. 7, the belt layer 1
0 is formed as a normal attachment, and therefore, in this example, a first-arrival area F is formed on the left side of the tire equator CO and a rear-arrival area R is formed on the right side of the tire equator CO. Further, in the first-arriving and second-arriving regions F and R, the tread edges E1 and E2 are formed in the lateral groove 10.
Between the vertical groove 9B and the intermediate groove 9B, respectively.
4 is formed.

In the falling groove portion 13 in the first-arrival area F,
The inclination angle θ2 of the groove wall surface of the first-arriving side is larger than the inclination angle θ1 of the groove wall surface of the later-arriving side, and the tilt angle θ4 of the groove wall surface of the later-arriving side in the falling groove portion 14 in the later-arriving region R is It is formed to be larger than the inclination angle θ3 of the groove wall surface on the first-arrival side.

12 and 13 show another embodiment of the tread pattern. In FIG. 12, a central vertical groove 21A that circulates along the tire equator CO and a central vertical groove 21A.
The inner ribs 22A, 22A and the outer ribs 22B, 22B are formed by the vertical grooves 21 formed of a pair of vertical grooves 21B, 21B respectively arranged between A and the tread edges E1, E2 on both sides.
Forming a tread pattern having four ribs.

The outer rib 22B has tread edges E1 and E2.
A continuous lateral groove 23A connecting between the vertical groove 21B on the side and the vertical groove 21B on the side extends to the rib 22A on the inner side from the vertical groove 21B on the side toward the four tire equator CO and is interrupted in the inner rib 22A. A horizontal groove 23B having a break, and a second horizontal groove 23C having a second vertical groove 21A extending from the central vertical groove 21A toward the tread edges E1 and E2 and being cut inside the rib 21A.
Have and. A lateral groove is formed by the continuous lateral groove 23A and the first and second lateral grooves 23B and 23C. Therefore, in this example, ribs and block patterns are formed on the tread surface 2A.

On the other hand, the belt layer 7 is formed on the outermost belt ply 11 as a regular attachment with its belt cord inclined upward to the left in the tire axial direction toward FIG. Therefore, in this example, a first-arrival area F is formed on the left side and a last-arrival area R is formed on the right side in FIG.

The fall groove portions 13 and 14 are formed between the tread edges E1 and E2 and the cut ends of the first cut lateral grooves 21B arranged on the inner rib 21A. 14 are formed respectively.

In FIG. 13, the lateral groove 23 arranged in the outer rib 22B having the structure shown in FIG.
It is formed by a third interrupted lateral groove 23D that extends from E2 toward the tire equator CO and that is interrupted by the outer rib 22B, and the first and second lateral grooves 23B and 23C having the above-described configuration. Eggplant

Further, the belt layer 7 is formed by normal attachment as in the case of FIG. 12, and in this example, a first-arrival area F is formed on the left side and a rear-arrival area R is formed on the right side in FIG.

In this example, the falling groove portions according to the above construction are formed between the tread edges E1 and E2 and the interrupted end of the third interrupted lateral groove 21D arranged on the outer rib 21B.

Accordingly, in the lateral groove 23, in the first-arriving region F, the tilted groove portion 13 is formed in which the inclination angle θ2 of the groove wall surface 16 on the first-arriving side is larger than the inclination angle θ1 of the groove wall surface 17 on the last-arriving side. On the other hand, in the trailing edge region R, the tilted groove portion 14 is formed in which the tilt angle θ4 of the groove wall surface 20 on the trailing side is larger than the tilt angle θ3 of the groove wall surface 19 on the trailing side. As described above, the present invention can be applied to various tread patterns.

The tire axial distance in the tire axial direction of the sloping groove portions 13 and 14 is at least ⅓ times the tire axial distance in the ground contact area of the tread surface 2A and in the first-arriving area F and the last-arriving area R. It is preferable that the tilt groove portions 13 and 14 are provided separately from each other in the ground contact area in order to effectively generate the rotation moment.

[0067]

SPECIFIC EXAMPLES Tires (Examples 1 to 8) having tire sizes of 225 / 50R16 and having the cross-sectional structure shown in FIG. 1 and the pattern structure shown in FIG. Was tested.
In addition, the tires (Comparative Examples 1 to 3) other than the configuration of the present application were also tested to compare the performances.

The test method is as follows. 1) Lateral flow test Attach a test tire to a 7J x 16 rim, and 2.0kg
With an internal pressure of / cm ² applied to the front and rear wheels of a FR passenger car of 3000cc class, it was run 100m at a speed of 50km / h on a flat road paved by hand, and the reciprocal of the lateral flow distance was compared. The index is shown with 100 as an example. The larger the value, the smaller the amount of cross flow and the better.

[0069]

[Table 1]

2) Test B Tire size is 175 / 65R14 and FIG.
Tires having the pattern configurations shown in Nos. 2 and 13 (Example 1
1 to 12 and Examples 21 to 22) were prototyped according to the specifications shown in Table 2 and their performances were tested to compare their performances with tires of the conventional configuration (Comparative Examples 11 and 21).

The test was carried out by mounting on a rim of 5 1 / 2JJ × 14 and applying an internal pressure of 2.0 kg, and an FF of 1600 cc class.
While mounted on the vehicle, a lateral flow test was conducted by the same method as the above-mentioned test A. The evaluation is indicated by an index with Comparative Examples 11 and 21 in each pattern being 100. The test results are shown in Table 2.

[0072]

[Table 2]

As a result of the test, it was confirmed that the tires of the respective examples had less lateral flow, the larger the tire size, and the more effective the tire having the block pattern was as compared with the rib pattern. did it.

[0074]

As described above, since the pneumatic tire of the present invention has the above-mentioned constitutions, it is possible to improve the one-way flow during traveling and enhance the straight traveling performance,
It can be preferably used as a tire for passenger cars.

[Brief description of drawings]

FIG. 1 is a meridian sectional view of a tire showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional perspective view showing the right half of the tire.

FIG. 3 is a developed plan view showing the tread pattern developed together with a belt layer.

FIG. 4A is a sectional view taken along the line PP, and FIG.
It is a -Q line sectional view.

FIG. 5 is a developed plan view showing another embodiment of the tread pattern developed together with the belt layer.

FIG. 6A is a cross-sectional view taken along the line U-U, and FIG.
It is a -V line sectional view.

FIG. 7 is a developed plan view showing another tread pattern.

FIG. 8A is a perspective view showing the action of the belt layer,
(B) is the JJ plan view.

FIG. 9A is a perspective view showing the action of the belt layer,
(B) is a plan view of the KK.

FIG. 10 is a plan view showing the action of the tread pattern.

FIG. 11 is a plan view showing the action of the tread pattern.

FIG. 12 is a developed plan view showing a tread pattern of another embodiment.

FIG. 13 is a plan view showing the action of the tread pattern.

FIG. 14 is a perspective view illustrating a residual CF.

FIG. 15 is a diagram thereof.

FIG. 16 is a diagram thereof.

FIG. 17 is a diagram illustrating the measurement results of residual CF and one-sided flow.

[Explanation of symbols]

 2 tread portion 2A tread surface 3 sidewall portion 4 bead portion 5 bead core 6 carcass 7 belt layer 9, 21 vertical groove 10, 22 lateral groove 11 outermost belt ply 12 belt cord 13 falling groove portion 14 falling groove portion 15 first-arriving side Groove wall surface 16 of the groove wall surface of the side to arrive later 19 Groove wall surface of the side to arrive in advance 20 Groove wall surface of the side to arrive later CO tire equator F first arrival area R last arrival area f first arrival direction r last arrival direction

Claims (3)

[Claims] 1. A carcass which folds from a tread portion through a sidewall portion and around a bead core of a bead portion, and a belt cord which is arranged inside the tread portion and on the outer side in the tire radial direction of the carcass and whose belt cord is inclined with respect to the tire equator. A pneumatic tire comprising a belt layer composed of a plurality of stacked belt plies, and further having a plurality of vertical grooves extending in the circumferential direction in the tread portion, and a lateral groove extending in a direction intersecting with the vertical grooves, The tread portion in the tire axial direction left and right with the tire equatorial plane as a boundary, the belt cord of the outermost belt ply in the radial direction is a first-arriving region which is a region on the first-arriving side when rolling the tire, and the other later-arriving region. In the first-arriving area, the groove wall surface on the first-arriving side of the lateral groove is in a direction in which the tread surface is first-arriving with respect to a normal line perpendicular to the tread surface. In addition, the groove wall surface on the side which is inclined at the inclination angle θ2 and is rearwardly inclined at an inclination angle θ1 in the direction in which the tread surface is rearwardly attached with respect to the normal line, and in the rearward attachment region, the lateral groove is firstly attached. The groove wall surface on the side inclines at a tilt angle θ3 in the direction in which the tread surface comes in first with respect to the normal line, and the groove wall surface on the side that arrives later inclines in the direction in which the tread surface arrives later at the normal line. In addition to tilting at θ4, the lateral groove includes tilted groove portions in which the tilt angles θ2 and θ4 are respectively larger than the tilt angles θ1 and θ3 in the first-arriving region and the second-arriving region, respectively. tire. 2. The transverse groove intersects with the longitudinal groove,
The pneumatic tire according to claim 1, wherein the tread portion is formed with a block pattern divided by these vertical grooves and lateral grooves. 3. The pneumatic tire according to claim 1, wherein the belt cord of the outermost belt ply in the radial direction is inclined at an angle of 16 to 26 degrees with respect to the tire equator.