JPH02212202A - Pneaumatic tire - Google Patents

Abstract

PURPOSE:To increase a grip force to a dry road surface without decreasing drainage performance by providing at least one circumferential main groove, and a plurality of inclined main grooves and inclined auxiliary grooves in a tread respectively, and setting the groove width of the inclined auxiliary grooves larger on one side. CONSTITUTION:A tread pattern includes a circumferential main groove 34 separating a tread part 32 along the circumference of a tire 30 and extending almost parallel to a tire equator surface, and a circumferential auxiliary groove 35 parallel to and apart from it. In a tread half separated by the circumferential main groove 34 and positioned on the outer side of a vehicle, a plurality of inclined main grooves 36 are provided extending from its end part diagonally in one direction to a tire rotation direction R and apart from each other. A plurality of inclined auxiliary grooves 38 are also provided in parts formed by the inclined main grooves 36 and adjacent along the tire circumference extending through the inclined main grooves 36. The groove width of the inclined auxiliary grooves 36 is set larger on the side of the circumferential main groove 34 than on the tread end side.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a pair of pneumatic tires that are installed in pairs on both sides of a vehicle, and in particular, relates to a pair of pneumatic tires that have great grip power and ground contact on dry road surfaces. , as well as exhibiting abrasion resistance and providing the required drainage performance, and furthermore,
This invention relates to a tire pair that reduces noise during tire transfer.

(Prior art) With the recent improvement in the performance of vehicles, there is a strong demand for tires that have the required drainage performance and have excellent grip. A tire having a tread pattern has been proposed.

Normally, in order to improve the grip of a tire, when it is installed on a vehicle, the pattern on the tread section located on the outside of the vehicle is changed in various ways to increase the rigidity of the tire at that tread section, and the tread on the inside of the vehicle is Those with a so-called asymmetric pattern in which more grooves are formed in the tread area than in the tread area on the outside of the vehicle, or those in which the negative ratio in the tread area located on the outside of the vehicle are smaller than the negative ratio in the tread center area. be.

For example, as shown in FIG. 3, there are a plurality of circumferential grooves 14 formed in the center of the tread portion 12 of the tire 10 and extending in the circumferential direction of the tire, and a plurality of circumferential grooves 14 that are symmetrically oblique with respect to the circumferential main groove. The slanted groove 16 has a substantially V-shape when viewed from the front in the tire rotation direction (R), and other circumferential grooves 18 are formed on the outer circumferential sides of the tread portion, and the negative ratio is in the tread center portion. For tires that are different between the outside and outside,
Since water is drained along these circumferential grooves 14 and 18, drainage performance when the vehicle is running straight is improved, and furthermore, tire noise is lower than tires with other tread patterns. It has the following advantages.

However, when the vehicle is turning, input from the road surface in the tire lateral direction directly acts on the groove walls of the circumferential grooves 18, causing the groove walls of the grooves 18 to be destroyed and the tire to wear out. I have a problem to say.

Additionally, since there are no grooves in the width direction of the tread, there is a problem in that when the vehicle turns on a wet road surface, it is practically impossible to expect any drainage effect. .

On the other hand, as shown in FIG. 4, from each end of the tread portion 12 in which the inclined grooves 16 symmetrically intersecting obliquely with respect to the circumferential groove 14 are formed, a shoulder portion 20 extends in the tread width direction. In a tire in which a plurality of lateral grooves 22 are formed in the circumferential direction of the tire, water is drained through the lateral grooves 22 when the vehicle turns. It has sufficient rigidity to withstand the input input, so it improves drainage performance when the vehicle turns.
This means that wear resistance can be improved.

However, when the tire is transferred, the land portions forming the lateral grooves 22 are violently hit against the road surface, which causes a problem of increased tire noise.

For this reason, as shown in FIG. 5, the inclined grooves 16, which are substantially square-shaped when viewed from the front in the tire rotational direction and are symmetrical and diagonal with respect to the circumferential grooves 14, are formed from each end of the tread portion 12 to the shoulders. 20, and other circumferential grooves 18 are formed at the ends of the tread, but since the groove ratio increases as a whole and the block rigidity decreases, There was a problem with the power decreasing.

In addition, in most conventional tires, each groove width is the same size, so it is not possible to fully demonstrate the function of the grooves, including the block pattern defined by the grooves. Ta.

The present invention was made in view of these problems, and provides a tire that exhibits great grip on dry roads, ground contact, and wear resistance without impairing drainage performance, and further reduces tire noise. Its purpose is to provide earphones.

(Means for Achieving the Object) In order to achieve this object, in a pair of pneumatic tires of the present invention that are mounted in pairs on both sides of a vehicle, each tire is symmetrical with respect to the center line of the vehicle. The tread pattern is formed in at least one circumferential main groove that extends in the tire circumferential direction and divides the tread portion, and in at least one of the divided tread portions, and the tread pattern is formed on at least one circumferential main groove that extends in the tire circumferential direction and divides the tread portion, and the tread pattern is formed on at least one of the divided tread portions, A plurality of inclined main grooves extending in one direction diagonally from the main groove in the tire rotation direction and opening into the circumferential main groove, and extending in one direction diagonally in the tire rotation direction between the adjacent inclined main grooves. and a plurality of inclined minor grooves,
The groove width of the inclined sub-groove located on the main groove side in the circumferential direction is made larger than the groove width of the inclined sub-groove located on the tread end side.

(Function) According to this pneumatic tire pair, since the tread pattern is line symmetrical with respect to the vehicle center line, that is, the bisector of the axle, when the vehicle is cornering, the left and right tires are applied diagonally forward in the right and left directions, respectively. Since the directions of the external forces acting from the two tires are relatively equal, the dry performance and cornering wear resistance of both tires are approximately equal.

In addition, the tread pattern includes at least one circumferential main groove extending in the circumferential direction of the tire, and at least one of the tread portions divided by the circumferential main groove. By including a plurality of inclined main grooves extending in the direction and opening into the circumferential main groove, sufficient drainage performance of the tire can be ensured.

In other words, when the vehicle is traveling straight, water is mainly discharged along the circumferential main groove, and when the vehicle is turning, water is mainly discharged along the inclined main groove, so regardless of whether the vehicle is traveling straight or turning. Therefore, sufficient drainage performance can be ensured.

These slanted main grooves generate less tire noise than the lateral grooves formed along the width of the tread, and on the other hand, they have better wear resistance during cornering than the circumferential main grooves, so they produce less tire noise. Abrasion resistance can be improved without affecting the wear resistance.

In addition, in the plurality of inclined sub-grooves extending between adjacent inclined main grooves, the groove width of the inclined sub-groove located on the circumferential main groove side is the same as the groove width of the inclined sub-groove located on the tread end side. Because it is larger than
without increasing the negative ratio at the tread edge.
The ground contact area of the tire can be increased. Note that these inclined sub-grooves also contribute to the drainage performance of the tire.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a view of the tread pattern of one of the tires constituting a pair of pneumatic tires of the present invention, seen from the front in the tire rotational direction indicated by the symbol R, and the internal structure of the inner structure of the tire is shown in the numerical radial direction. The other tire is omitted here because its tread pattern is symmetrical with respect to the vehicle center line, that is, the bisector x-X of the axle.

The tread pattern divides 30 tread parts 32 of the tire in the circumferential direction of the tire, and includes circumferential main grooves 34 extending substantially parallel to the tire equatorial plane and circumferential sub-grooves 34 spaced apart parallel to the circumferential main grooves 34. A groove 35 is provided.

Here, in addition to the circumferential main groove 34, the sub groove 35 extending in the circumferential direction of the tire is formed in order to improve water drainage performance when the vehicle travels straight. Although the number of grooves is one each, the number is not limited to this, and the number of circumferential main grooves and sub-grooves can be increased.

In addition, in this embodiment, the tread pattern is formed on the tread half 32a that is formed by the circumferential main groove 34 and is located on the outer side of the vehicle when the tire is mounted on the vehicle. A plurality of inclined main grooves 36 are provided, which extend in one direction diagonally from the end of the tread half 32a with respect to the tire rotation direction R at an angle θ of .degree., and are spaced apart at predetermined intervals in the tire circumferential direction.

One end of each of the inclined main grooves 36 extends beyond the circumferential sub-groove 35 and opens into the circumferential main groove 34, while the other end extends to a shoulder portion 38 of the tread half located on the outside of the vehicle. There is.

Preferably, as shown in this embodiment, the groove width of the inclined main groove 36 is gradually increased from the circumferential main groove 34 side toward the end of the tread half, that is, from the center of the tread toward the outside of the vehicle. On the other hand, by gradually decreasing the groove depth and making the cross-sectional area of the inclined main groove 36 on the circumferential main groove side substantially equal to or larger than the cross-sectional area of the inclined main groove on the tread end side, those slopes can be reduced. In addition to ensuring the amount of water that can be drained along the main grooves, the rigidity at the tread ends of the portions defined by the inclined main grooves 36 and adjacent to each other in the tire circumferential direction is thicker than that at the center of the tread. do.

Further, the tread pattern is provided with a plurality of inclined sub-grooves 38 extending between adjacent inclined main grooves in each portion adjacent to each other in the tire circumferential direction defined by the inclined main grooves 36, The inclined sub-grooves 38 are such that the groove width of the inclined sub-groove located on the side of the circumferential main groove 12 is larger than the groove width of the other inclined sub-grooves located on the tread end side from the said inclined sub-groove. do.

These inclined sub-grooves extend diagonally in one direction in the tire rotation direction R with respect to the circumferential main groove 34, and are associated with each inclined sub-groove 38 in the tire depression shape indicated by the symbol F in the figure. With respect to the normal P, ~P3, the circumferential main groove 34
The angles α, α1, ., α1, . It is preferable to set α to ±35° or less. By setting this angle range, the extending direction of the inclined sub-groove 38 approaches the normal direction of the tire depression shape F, and its tangent line Since it is not oriented in any direction, it contributes to reducing tire noise.

In addition, the groove width of the inclined minor groove located on the circumferential main groove 34 side is
By making the groove width larger than the groove width of the inclined sub-groove located on the tread end side of the inclined sub-groove, the inclined sub-groove located on the circumferential main groove 34 side mainly contributes to drainage performance when the vehicle runs straight. On the other hand, the inclined sub-groove 3 located on the tread end side
8 substantially increases the ground contact area on the tread end side, contributing to an increase in the grip force of the tire.

Note that by providing three or more inclined minor grooves 38, the above performance can be fully exhibited, and the circumferential main groove 3
Grip force can be increased by gradually decreasing the groove width of each of the inclined sub-grooves 38 as you move from the 4 side to the tread end side, thereby further increasing the ground contact area at the tread end side.

Furthermore, the angle between the circumferential main groove 34 and the inclined main groove 36 is θ.
The respective angles of the inclined sub-grooves 38 located sequentially from the circumferential main groove 34 side to the tread end side with respect to the circumferential main groove 34 are set at θ7.0. 03, these angles are selected to satisfy the following relationship.

θ>θ3>θ,>θ.

In order to satisfy such a relationship, the angle between the inclined sub-groove 38 and the circumferential main groove 34 becomes thicker as it moves from the center of the tire to the end of the tread, so that when the vehicle turns, The lateral human force acting on the groove walls of the inclined sub-grooves 36 is separated into a component perpendicular to the groove walls and a component along the groove walls, thereby improving wear resistance.

In addition, the groove width of the inclined sub-groove 38 is set to the tire depression shape F.
On the other hand, by gradually decreasing the stiffness from the stepping side toward the kicking side, the rigidity of the block portion defined by the inclined main groove 36 and the inclined minor groove 38 on the stepping side is
Since the rigidity can be made smaller than that on the kicking side, the force acting on the tire when stepping is absorbed by the deformation of the stepping side block portion, and abnormal wear on the stepping side where the tire makes contact with the ground can be suppressed.

In addition, as the groove width of the inclined minor grooves extending between mutually adjacent inclined main grooves gradually decreases in the direction in which the minor grooves extend, the negative ratio in the block portion gradually decreases, and the negative ratio in the block portion gradually decreases. Rigidity increases smoothly as it moves from the circumferential main groove position to the tread edge.
This results in improved handling stability.

Furthermore, by extending the inclined sub-grooves 38 over the block portions defined in the inclined main groove 36 and adjacent to each other in the tire circumferential direction, and gradually decreasing the groove width of the inclined sub-grooves in the extending direction. , the rigidity of the block portion can be made even smoother, and the steering stability can be further improved.

In addition, in this embodiment, the tread pattern extends from the tread end in one diagonal direction in the tire rotation direction R in the other side of the tread portion divided by the circumferential main groove 34, similarly to the inclined main groove 36. and one end thereof is the circumferential main groove 36.
The other end extends beyond the tread edge to the shoulder part 3.
8, and inclined sub-grooves 42 that are formed at a predetermined distance in the circumferential direction of the tire and extend between the adjacent inclined main grooves.

The respective functions of the inclined main groove 40 and the inclined sub-groove 42 are substantially the same as those of the inclined main groove 36 and the inclined sub-groove 38 which are adjacent to each other via the circumferential direction main groove 34, so the description thereof will be omitted. However, what should be noted here is that the inclined main groove 40
is that the inclined main grooves 36 are formed at predetermined intervals in the circumferential direction of the tire, and are shifted by about half a pitch in the circumferential direction of the tire.

This ensures the drainage function along the circumferential main grooves 34 and the inclined main grooves 36 and 40 that open into the circumferential main grooves, respectively.
Since the edges of the respective block portions, which are defined by 0 and are opposed to each other via the circumferential main groove 34, can resist movement in the lateral direction of the tire, straight-line stability is improved. Further, since the edges of each block portion do not match the depression shape F, tire noise can be reduced.

Furthermore, by providing the inclined main groove 40 and the inclined sub-groove 42, the negative ratio of the tread portion located on the inside of the vehicle when mounted on the vehicle is increased, and drainage performance can be improved. Since the rigidity of the block portion can be set low in that part, the ground contact performance is also improved. .

In addition, in this example, although the inclined main groove and the inclined sub-groove were respectively formed in each tread part defined by the circumferential direction main groove 34, it is not limited to this, and one tread In this case, when the tread is mounted on the vehicle, the tread portions where the inclined main grooves and the inclined sub-grooves are not formed are located on the outside of the vehicle. It shall be installed so that it is in the correct position.

[Comparative Example] Comparative tests regarding dry performance, wet performance, tire noise, and wear condition during cornering between the tire according to the present invention and a conventional tire will be described below. The test was conducted with the tire mounted on the vehicle as shown in FIG.

◎Radial structure tire with test tire size 225150VR16.
Invention Tire A tire having the tread pattern shown in Figure 1, with a tread width of 204 mm and a maximum circumferential main groove width of 13III1.
Circumferential main groove depth 9m, inclined main groove maximum width 6.3 m, inclined main groove maximum depth 8III, circumferential pitch 50III
I, the maximum width of the inclined sub-groove is 3.6 mm, and the depth of the inclined sub-groove is 8 mm.

・Conventional tires A tire having a directional pattern shown in FIGS. 3 to 5.

◎Test method - Dry performance - The above tires were installed alternately on a car, and the lateral acceleration in a feeling test and a steady circular turning test with a radius of 30H was measured and converted into an index.

・Wet performance The limit straight speed and limit turning speed on a road surface with water depth as IO- were measured and converted into an index.

・Based on tire noise JI3 (car body bench test was conducted, sound pressure was measured and indexed).

·wear The wear rate after running 10,000 km was measured and converted into an index.

According to the above table, it is clear that compared to tires with conventional patterns, it is possible to improve dry performance and wear resistance while ensuring the required drainage performance, and to reduce tire noise.

(Effects of the Invention) As detailed above, according to the present invention, as shown in the table above, grip power and wear resistance can be sufficiently improved without sacrificing drainage performance, and tire noise can be reduced. can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram schematically showing the vehicle mounting position of the tire shown in FIG. 1, and FIGS. 3 to 5 are diagrams showing a conventional tread. It is a figure which shows each pattern. R...Tire rotation direction ...Circumferential independent groove 20.38...Shoulder part 22...Horizontal groove 34...Circumferential main groove 35...Circumferential minor groove 36.40...Slanted main groove 38.42...・Slanted minor groove Patent applicant Brideston Co., Ltd. Figure 1 To Figure 2 To Figure 3 - To - 1〒J 20 /2
20Figure 4Figure 5

Claims (1)

[Scope of Claims] 1. A set of pneumatic tires installed in pairs on both sides of a vehicle, each of which has a tread pattern that is symmetrical with respect to the center line of the vehicle. The tread pattern is formed in at least one circumferential main groove that extends in the tire circumferential direction and divides the tread portion, and in at least one of the divided tread portions, and extends in the tire rotation direction from the tread end side. A plurality of inclined main grooves extending diagonally in one direction and opening into the circumferential main groove, and a plurality of inclined sub-grooves extending diagonally in one direction in the tire rotation direction between the mutually adjacent inclined main grooves. and a groove;
A pair of pneumatic tires characterized in that the groove width of the inclined sub-groove located on the circumferential main groove side is larger than the groove width of the inclined sub-groove located on the tread end side. 2. Claim 1, in which there are three or more inclined sub-grooves, and the groove width of each of the inclined sub-grooves is gradually decreased toward the tread end side.
Pneumatic tires as described in Section. 3. The angle between the circumferential main groove and the inclined main groove is θ, and the angle between the plurality of (n) inclined sub-grooves gradually spaced apart from the circumferential main groove and a plane parallel to the circumferential main groove is respectively θ_1, θ_
2,...θ_n, these angles are θ>θ_n>θ_(_n_-_1_)>...>θ_1
A pair of pneumatic tires according to claim 1, which satisfies the following relationship. 4. The pneumatic tire pair according to claim 1, wherein the groove width of each inclined sub-groove is gradually decreased from the tire stepping side to the kicking side. 5. The inclined minor grooves are defined by the inclined main grooves and extend over the land portions adjacent to each other in the circumferential direction of the tire, and the width of the inclined minor grooves is directed from the tire stepping side to the kicking side. A pair of pneumatic tires according to claim 1, which are gradually reduced. 6. The air compressor according to claim 1, wherein the tread portion in which the inclined main groove and the inclined sub-groove are formed is located on the outside of the vehicle when viewed from the front in the rotational direction when the tire is mounted on the vehicle. Entering tires vs.