JPH03243403A - Radial tire for automobile - Google Patents

Abstract

PURPOSE:To make directionality of each block uniform and reduce a residual lateral force and an amount of shift of a vehicle by placing V-shaped portions in a plurality of blocks provided on a tread and a plurality of edges for regulating the portions so that specific conditions are respectively satisfied. CONSTITUTION:Numerous blocks 12 to 20, 24 are provided on a tread pattern 10 of a tire. At least the first and second blocks 12, 14 have V-shaped portions which are regulated by a plurality of edges 26, 28 extending at respectively predetermined angles theta1, theta2 with respect to a virtual line perpendicular to a tread center 22. In this case the respective V-shaped portions of at least the first and second blocks 12, 14 are placed between V-shaped portions on the respective blocks 12, 14 adjacent to a peripheral direction of a tire. Most parts of the respective edges 26, 28 are made opposite to the respective corresponding edges 26, 28 of the respective blocks 12, 13 adjacent to the peripheral direction of the tire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radial tire for automobiles having a block-type tread pattern.

(Prior Art) In a radial tire in which a steel belt is disposed in the breaker layer, when the vehicle is driven straight with one's hands off the steering wheel, the vehicle gradually displaces in the lateral direction (the present invention (This phenomenon is called a "vehicle flow phenomenon," and its magnitude is called a "flow amount.") The vehicle drift phenomenon occurs when the hands are off the steering wheel, that is, when the self-lining torque (SA
When T) is zero, the large residual lateral force (sight force -5
F) is thought to occur when

In order to prevent the occurrence of vehicle drifting, conventional methods have been used to reduce the residual lateral force generated by the steel belt of the breaker layer and the slope of the road surface (in Japan, where people drive on the left, descending to the left, etc.)
In order to prevent the residual lateral force that occurs due to the right-hand traffic (downhill in the United States and other countries where traffic is on the right) from canceling out and thereby causing the residual lateral force to become an abnormal value, the court is The steel belt was arranged so as to extend in the direction shown in FIG.

(Problem to be Solved) However, in conventional lithium tires with block-type tread patterns, even if the steel belt of the breaker layer is arranged as described above, a large residual lateral force is generated, resulting in The flow rate is large. This is considered to be due to the directionality of the blocks in the tread pattern, which generates lateral force upon contact with the ground.

SUMMARY OF THE INVENTION An object of the present invention is to provide a radial tire for an automobile having a block-type tread pattern with low residual lateral force and low vehicle flow rate.

(Solution, Operation, Effect) The radial tire of the present invention has a first edge extending in a direction having an angle θ1 with respect to an imaginary line perpendicular to the tread center, and a first edge extending in a direction having an angle θ2 with respect to the imaginary line. 2
A plurality of blocks each having a substantially figure-9-shaped portion defined by an edge of the block, the blocks being arranged sequentially in the circumferential direction of the tire such that the figure-9-shaped portions are alternately oriented in opposite directions in the axial direction of the tire. The tread pattern includes a plurality of blocks.

Each of the blocks in the tire of the present invention includes the 9
The block is located between the letter-shaped portions of the two blocks adjacent in the circumferential direction of the tire, and most of the first and second edges are adjacent to each other in the circumferential direction of the tire. are arranged to face corresponding first and second edges of.

Therefore, according to the radial tire of the present invention, the directionality of the blocks in the tread pattern is averaged, and as a result, the residual lateral force generated due to the tread pattern is small, and the flow rate of the vehicle is small.

Preferably, the angles θ and θ2 are greater than 25 degrees and less than 50 degrees, and the difference between the angles θ1 and 02 is less than 10 degrees. When the angles θ and θ2 are 50 degrees or more, the angles of the 9-shaped portions, that is, the first and second
Since the angle (θ1+02) defined by the edge of is too large, the rigidity of the block is too low. If the angles θ1 and θ2 are less than 25 degrees, the appearance is unfavorable. When the difference between the angles θ1 and 02 becomes 10 degrees or more,
When lateral forces occur due to block deformation of the pattern, it becomes difficult for each lateral force to cancel out.

When siping is formed in each of the blocks, the siping may extend in the width direction of the tire at an angle of less than 15 degrees with respect to the imaginary line.

The tread pattern further has an angle θ with respect to the virtual line.
3 and a fourth edge extending in a direction having an angle θ4 with respect to the imaginary line. Preferably, the 9-shaped portion includes a plurality of other blocks sequentially arranged in the circumferential direction of the tire so as to be alternately oriented in opposite directions in the axial direction of the tire.

In the above case, the respective blocks are located between the character 9-shaped portion thereof or the character 9-shaped portion of two other blocks adjacent in the circumferential direction of the tire, and the third and fourth blocks
Most of the edges of the blocks are arranged so as to face the corresponding third and fourth edges of the other blocks adjacent in the circumferential direction of the tire. This further reduces residual lateral forces caused by the tread pattern.
Vehicle flow rate becomes smaller.

The angles θ3 and θ4 may be greater than 25 degrees and less than 50 degrees, and the difference between the angles θ1 and θ2 may be less than 1 degree.

(Example) The tread pattern 1° of the tire shown in FIG. A plurality of second blocks 14 located nearby and arranged sequentially in the circumferential direction of the tire, and a plurality of third blocks 14 located outside the second blocks in the width direction of the tire and arranged sequentially in the circumferential direction of the tire. a block 16, a plurality of fourth blocks 18 located near the third block and arranged sequentially in the circumferential direction of the tire, and a plurality of fourth blocks 18 located outside the fourth block in the width direction of the tire in the circumferential direction of the tire. It has a plurality of fifth blocks 20 arranged sequentially in the tread center 22 on both left and right sides of the tread center 22, and a plurality of sixth blocks 24 arranged sequentially in the circumferential direction of the tire at the center in the width direction of the tire. has.

Each of the first and second blocks 12 and 14 has an angle θ1 with respect to an imaginary line perpendicular to the tread center 22.
It has a substantially figure-9-shaped portion defined by two edges 26 and 28 extending in the direction of θ2 and θ2. 1st
And each of the second blocks 12 and 14 is located between the figure 9-shaped portion or the figure 9-shaped portion of the block 12 or 14 adjacent in the circumferential direction of the tire, and has large edges 26 and 28. Corresponding edges 26 and 2 of blocks 12 or 14 whose portions are adjacent in the circumferential direction of the tire
It is arranged to face 8.

Each of the third and fourth blocks 16 and 18 has an angle θ3 with respect to an imaginary line perpendicular to the tread center 22.
It has a substantially figure-9-shaped portion defined by two edges 30 and 32 extending in the direction of and θ4. Third
And each of the fourth blocks 16 and 18 also has a shape in which the 9-shaped portion is located between the 9-shaped portions of adjacent blocks 16 or 18 in the circumferential direction of the tire, and the edges 30 and 32 are large. Corresponding edges 30 and 3 of blocks 16 or 18 whose portions are adjacent in the circumferential direction of the tire
It is arranged to face 2.

Each of the first and second blocks 12 and 14 has sipings 34 and 36 extending toward the figure-9 portion from the opposite side to the figure-9 portion. Each of the sipings 34 and 36 is bent in a zigzag shape around lines extending in directions having angles α1 and α2 with respect to an imaginary line perpendicular to the tread center 22.

Third. 4th and 6th blocks 16° 18 and 24
each also has a plurality of sipings 38. Each thigh pink may be straight or curved as in the illustrated example.

Angle θ1. θ2. Each of θ3 and θ is selected to be greater than 25 degrees and less than 50 degrees, and the difference between angles θ and θ2 and the difference between angles θ3 and 04 is less than 10 degrees. The angles α1 and α, are selected to values of the order of 15 degrees.

The first block 12 and the sixth block 24, the second block 14 and the third block 16, and the fourth block 18 and the fifth block 20 each extend continuously in the circumferential direction of the tire. It is demarcated by a groove defined by both corresponding blocks. The blocks adjacent in the circumferential direction of the tire are at an angle θ1. θ2. θ3. a groove 40, 42° 44.46 extending in a direction having θ and defined by corresponding edges;
It is divided by.

The tread pattern 10 includes first to sixth blocks 12,
A plurality of basic patterns consisting of 14, 16, 18, 20.24 and having different pitches are irregularly arranged in the circumferential direction of the tire.

The tread pattern 48 of the tire shown in FIG. 2 has no sixth block, and the first blocks 12 adjacent to each other in the width direction of the tire have grooves extending in the circumferential direction of the tire on the tread center 22. The tread pattern has almost the same pattern shape as the tread pattern 10 except for defining the tread pattern 10.

The first to fifth blocks 12 in the tread pattern 48
The edges 26, 28, 30, and 32 that define the figure 9-shaped portion of 20 are respectively at an angle θ1. θ2. It extends in the direction having θ3 and θ4. Angle θl, θ2. Each of θ3 and θ4 is the same as the corresponding angle of the tread pattern 10.

(Experimental Example) A tire of Example 1 having a tread pattern 10 shown in FIG. 1, a tire of Example 2 having a tread pattern 48 shown in FIG. 2, and a tread pattern 5 shown in FIG.
A tire of Comparative Example 1 having a tread pattern 52 shown in FIG. 4 and a tire of Comparative Example 2 having a tread pattern 52 shown in FIG.

The vehicle flow rate and residual lateral force obtained by installing these tires on a car are calculated based on the tire size, θ1°θ2. θ3. θ
4. α1. It is shown in Table 1 along with α2. In Table 1, 0
1 to θ4 differ depending on the pitch of the basic pattern.

The steel belt of the breaker layer is arranged so that it becomes a right-down road tire (so that the residual lateral force generated by the belt and the residual lateral force caused by the right-down road surface cancel each other out). did.

The amount of lateral flow of the vehicle was determined by measuring the displacement of the vehicle in the left-right direction when a vehicle equipped with tires was driven straight on a flat road surface, then the driver took his hands off the steering wheel, and the vehicle was driven for an additional 100 m.

The residual lateral force was determined by measuring the force applied to the shaft at a slip angle of 0 degrees using an indoor bench tester.

In the column of vehicle flow amount in Table 1, "left" means that the vehicle has shifted in the opposite direction to the sideways flow direction (rightward) due to the downward-sloping road surface, and "right" means that the vehicle This means that the vehicle has shifted in the direction of horizontal flow (to the right) due to the road surface sloping down to the right.

In addition, in Table 1, the fact that the residual lateral force is negative means that the force that causes the vehicle to shift in the opposite direction (to the left) from the direction in which the vehicle flows laterally (to the right) due to the road surface descending to the right is applied to the vehicle. A residual lateral force of 10 means that a force acting on the vehicle causes the vehicle to move laterally (to the right) due to the road surface sloping down to the right.

As is clear from Table 1, according to the tires of Examples 1 and 2, the vehicle flow and residual lateral force generated due to the tread pattern are the same as the vehicle flow and residual lateral force generated due to the slope of the road surface, respectively. Acts to cancel lateral forces.

On the other hand, in the tires of Experimental Examples 1 and 2 having a tread pattern of 50.52 in which diamond-shaped blocks are arranged,
The vehicle flow and residual lateral force generated due to the tread pattern act in addition to the vehicle flow and residual lateral force generated due to the slope of the road surface, respectively.

The tires of Examples 1 and 2 have a leftward flow rate and a residual lateral force of -, so they are suitable as tires for right-down road surfaces. In order to make it suitable for use on a left-down road surface, the steel heald of the tire breaker layer may be arranged in the opposite way to that in Examples 1 and 2.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the tread pattern of the tire of the present invention, FIG. 2 is a diagram showing another example of the tread pattern of the tire of the present invention, and FIG. 3 is a diagram showing the tread pattern of the tire of the present invention. A diagram showing a tread pattern. FIG. 4 is a diagram showing a tread pattern used in a tire of Comparative Example 2. 10.48: l-red pattern, 12.14.16, 18 niblock, 22. tread center, 26.28, 30, 32: edge.

Claims (6)

[Claims] (1) Angle θ_ with respect to the virtual line orthogonal to the tread center
1 and a second edge extending in a direction having an angle θ_2 with respect to the virtual line, the plurality of blocks having a substantially V-shaped portion defined by a first edge extending in a direction having an angle θ_2 with respect to the virtual line; A radial tire for an automobile having a tread pattern including a plurality of blocks sequentially arranged in the circumferential direction of the tire such that the letter-shaped portions are alternately oriented in opposite directions in the axial direction of the tire, wherein each of the blocks has its V The V-shaped portions of the two blocks are adjacent to each other in the circumferential direction of the tire, and at least a portion of the first and second edges are adjacent to each other in the circumferential direction of the tire. A radial automotive tire disposed opposite corresponding first and second edges of the block. (2) The angles θ_1 and θ_2 are greater than 25 degrees and less than 50 degrees, and the difference between the angles θ_1 and θ_2 is 10 degrees.
The radial tire for an automobile according to claim 1, wherein the radial tire is less than 30%. (3) The radial tire for an automobile according to claim 2, wherein each of the blocks has sipings extending in a direction having an angle of less than 15 degrees with respect to the imaginary line. (4) The tread pattern is further defined by a third edge extending in a direction having an angle θ_3 with respect to the imaginary line and a fourth edge extending in a direction having an angle θ_4 with respect to the imaginary line. A plurality of other blocks having V-shaped portions, the plurality of other blocks being sequentially arranged in the circumferential direction of the tire such that the V-shaped portions are alternately oriented in opposite directions in the axial direction of the tire. and each of the other blocks has its V-shaped portion located between the V-shaped portions of two adjacent other blocks in the circumferential direction of the tire and between the third and fourth edges. The radial tire for an automobile according to claim (1), wherein at least a portion thereof is arranged to face the corresponding third and fourth edges of the other blocks adjacent to each other in the circumferential direction of the tire. . (5) The angles θ_3 and θ_4 are greater than 25 degrees and less than 50 degrees, and the difference between the angles θ_1 and θ_2 is 10 degrees.
The radial tire for an automobile according to claim (4), which is less than 30%. (6) The first, second, third and fourth edges of the blocks adjacent in the circumferential direction of the tire are at the angles θ_1, θ_2, θ_3 and θ_ with respect to the virtual line, respectively.
4. The radial tire for an automobile according to claim 4, wherein the tire defines a groove extending in a direction having a direction of 4.