JP2010047211A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to easily recognize asymmetry in pattern appearance while minimizing the difference between right and left in pattern performance in a pneumatic tire in which a mounting direction is specified. <P>SOLUTION: A center rib 18 and shoulder blocks 34 are made point-symmetrical, respectively, intermediate blocks 24 arranged at both sides of a tire equatorial plane CL are configured so that outer shapes of one and the other with the tire equatorial plane as a boundary are point-symmetrical and groove shapes inside the blocks are not point-symmetrical according to the internal structure which is asymmetric on the right and left, and therefore it becomes easy to recognize the direction of mounting the tire to a vehicle (inside and outside) compared with the case that the shape of the intermediate blocks are perfectly point-symmetrical. Furthermore, because the center rib 18 in the center side in the width direction of a tread 12 and the shoulder blocks 34 in the shoulder side are point-symmetrical on the right and left of the tire equatorial plane CL, the pattern of the total tread becomes generally point-symmetrical, and therefore the difference between the right and left in performance can be inhibited. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire in which the mounting direction, that is, the inner side and the outer side when the vehicle is mounted (OUT SIDE is indicated on the tire side portion) is designated.

As a tread pattern of a pneumatic tire, there are a configuration in which left and right are point-symmetric when divided at the center in the left-right direction (see, for example, Patent Document 1), and a configuration with directionality by inverting the left and right. Many have been developed.
In recent years, many asymmetric configurations that cannot be divided at the center in the left-right direction have come to be seen.

  The point-symmetric or directional configuration is used to develop performance at the tread center (near the tire equator), the middle between the tread center and end, and the tread end (near the shoulder). On the other hand, the asymmetric configuration has a tendency to more clearly divide the role of performance for each row in the land, and particularly to change the rigidity of the land.

By the way, in developing the performance of the entire tire, the performance of the tread pattern is determined in close cooperation with other elements (structure, shape, rubber physical properties, etc.).
For example, while adopting an asymmetric structure (see, for example, Patent Document 2) for the other elements described above, the tread pattern sometimes requires point-symmetric performance with little difference between right and left. Even in such a case, it is necessary to know that the appearance of the product is asymmetrical when mounted on the vehicle.
JP 2006-27498 A JP 2000-238505 A

In general, in tires for which the inner side and the outer side are designated, a display such as OUT SIDE is given to the tire side portion, but there are cases where the display is overlooked and the mounting direction is wrong.
For this reason, it can be said that it is preferable that the tread pattern that is easily noticeable can be distinguished from the direction in which it is worn. However, heretofore, there has been no tire that can meet the requirement to simultaneously achieve this asymmetrical appearance and point-symmetric performance (minimizing the left-right difference in pattern performance).

  The present invention has been made in order to solve the above-described problem. At least one of the internal structure and the cross-sectional shape along the tire rotation axis is asymmetrical on the left and right of the tire equatorial plane, and the installation direction is specified. An object of the present invention is to make it possible to easily determine asymmetry in the pattern appearance while minimizing the left-right difference in pattern performance.

  The present invention has been made in view of the above-mentioned fact, and the invention according to claim 1 is characterized in that at least one of the internal structure and the cross-sectional shape along the tire rotation axis is asymmetrical on the left and right of the tire equatorial plane. A plurality of circumferential main grooves formed in the tread, and a plurality of land portions that are provided in the tread and defined by the plurality of circumferential main grooves. The tire land portion on the outermost side in the tire axial direction on the one side and the shoulder land portion on the outermost side in the tire axial direction on the other side are in a point-symmetric relationship with the tire equator plane as a boundary. Also, the intermediate land portion on one side and the intermediate land portion on the other side of the tire equator surface of the pair of left and right intermediate land portions disposed on both sides of the tire equator surface are points. Not symmetrical.

Next, the operation of the pneumatic tire according to claim 1 will be described.
In the pneumatic tire according to claim 1, the tire equatorial plane side of the tire equator plane from the shoulder land portion and a pair of left and right intermediate land portions disposed on both sides of the tire equator plane are used as boundaries. Since the intermediate land portion and the intermediate land portion on the other side are not point-symmetrical, it is easier to distinguish the inner side and the outer side of the tire than when the point is point-symmetric.

  In addition, the tread pattern has little difference between the left and right, because the tread has a point-symmetrical pattern in the region on the center side in the width direction and the region on the shoulder side. Performance can be obtained.

  In the tread pattern, in general, the center part in the width direction of the tread and the shoulder part are relatively important, and the middle part of these two parts is a part where the demand level is lower than the former part. It has become. For this reason, as in the pneumatic tire of claim 1, the pair of left and right intermediate land portions arranged on the tire equator plane side and on both sides of the tire equator plane are arranged on the tire equator plane side from the outermost shoulder land portion in the tire axial direction. Even with point symmetry, the left-right performance difference can be suppressed.

  The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the intermediate land portion on one side and the intermediate land portion on the other side are point-symmetric with respect to the tire equator plane, The groove shape in the part is set asymmetry.

Next, the operation of the pneumatic tire according to claim 2 will be described.
With the tire equator plane as a boundary, the intermediate land on one side and the intermediate land on the other side are point-symmetric in outer shape and the groove shape in the land is non-point-symmetric, improving the point-symmetric property. Can ensure the difference in appearance.

  According to a third aspect of the present invention, in the pneumatic tire according to the first or second aspect, the total width in the tire axial direction of the intermediate land portion is 35-60 of the total width of the entire land portion of the tread. %.

Next, the operation of the pneumatic tire according to claim 3 will be described.
By setting the total width of the intermediate land portion in the tire axial direction to 35-60% of the total width of the tread land portion, the difference in appearance becomes clearer and the performance difference between the left and right of the tread is affected. It can be suppressed to the range where there is no.

  If the total width of the intermediate land portion in the tire axial direction is less than 35% of the total width of the entire land portion, the intermediate land portion becomes too small and it becomes difficult to understand the difference in appearance from the case of point symmetry. On the other hand, when the total width of the intermediate land portion in the tire axial direction exceeds 60% of the total width of the entire land portion, the intermediate land portion becomes too large and the influence of the left and right performance difference of the tread becomes conspicuous.

  The invention according to claim 4 is the pneumatic tire according to any one of claims 1 to 3, wherein the distance A from the intermediate land portion on one side of the tire equatorial plane to the tire equatorial plane; The distance B from the intermediate land portion on the other side of the tire equator plane to the tire equator plane is different.

Next, the operation of the pneumatic tire according to claim 4 will be described.
By making the distance A from the middle land on one side of the tire equator to the tire equator and the distance B from the middle land on the other side of the tire equator to the tire equator, It can be made clearer.

  As described above, according to the present invention, in a pneumatic tire in which at least one of the internal structure and the cross-sectional shape along the tire rotation axis is asymmetrical on the left and right of the tire equator plane, It becomes easy to judge the inside and outside of the time.

[First Embodiment]
Hereinafter, a pneumatic tire according to a first embodiment of the present invention will be described with reference to the drawings.
As shown in the cross-sectional view of FIG. 2, the pneumatic tire 10R of the present embodiment has a left side (arrow IN direction side in FIG. 2) on the inside of the vehicle and a right side (arrow OUT direction side in FIG. 2) on the vehicle. It is a tire for the right wheel that is mounted on the vehicle so as to be on the outside.

  In the pneumatic tire 10R, on the outer side in the tire radial direction of the carcass 42, for example, a first belt ply 44 and a second belt ply 46, in which a plurality of steel cords are arranged in parallel and coated with rubber, are disposed. 46, a belt reinforcing layer 48 in which a plurality of organic fiber cords are arranged in parallel and rubber-coated is arranged on the outer side in the tire radial direction so as to cover the entire belt layer. Edge bands 50 and 52, in which a plurality of organic fiber cords are arranged in parallel and coated with rubber, are arranged on the outer side in the tire radial direction on the (IN direction side), and the internal structure is asymmetrical.

  As shown in FIG. 1, the tread 12 of the pneumatic tire 10R of the present embodiment is formed with first circumferential main grooves 14 extending along the tire circumferential direction on both sides of the tire equatorial plane CL. A second circumferential main groove 16 extending along the tire circumferential direction is formed on the axially outer side. Note that the first circumferential main groove 14 and the second circumferential main groove 16 preferably have a groove width of 3 mm or more.

  Center ribs 18 defined by a pair of first circumferential main grooves 14 are disposed on the tire equatorial plane CL. In the present embodiment, the tire equatorial plane CL coincides with the center of the center rib 18 in the width direction. Further, the center rib 18 is formed with a plurality of short sipes 20 that are connected to the first circumferential main groove 14 at one end and inclined to the right and terminate at the other end in the land portion in the tire circumferential direction. . When the center rib 18 is divided into a right part and a left part of the tire equatorial plane CL, the right part and the left part have a point-symmetric relationship.

  In the land portion between the first circumferential main groove 14 and the second circumferential main groove 16, in the present embodiment, first lug grooves 22 that incline to the right are spaced apart in the tire circumferential direction. A plurality of intermediate blocks 24 are defined by the first circumferential main groove 14, the second circumferential main groove 16, and the first lug groove 22.

The intermediate block 24 is formed with a narrow lug groove 26 that is narrower than the first lug groove 22 and slopes upward to the right, and tilts upward to the left to move the intermediate block 24 substantially in the block width direction. A sipe 28 that traverses and a sipe 30 that slopes upward to the right are formed.
In addition, the thin lug groove 26 of this embodiment is formed in the circular arc shape which has a curvature center on the left side of the drawing, and the width is gradually reduced toward the stepping side. Further, the sipe 28 of this embodiment is formed in an arc shape having a center of curvature on the left side of the drawing.

  In the present embodiment, the right intermediate block 24 and the left intermediate block 24 of the tire equatorial plane CL have the same shape and face the same direction. That is, the intermediate block 24 is asymmetrical (non-linearly symmetric) about the tire equatorial plane CL as an axis of symmetry. More specifically, the outer shape of the intermediate block 24 on the right side of the tire equatorial plane CL and the outer shape of the intermediate block 24 on the left side are point-symmetrical, but the groove shape (thin lug groove) of the intermediate block 24 on the right side of the tire equatorial plane CL 26) and the groove shape of the left intermediate block 24 are not point-symmetric.

  The tread 12 is formed with a plurality of second lug grooves 32 extending from the second circumferential main groove 16 toward the outer side in the tire axial direction and inclined slightly upward to the right in the tire circumferential direction. A plurality of shoulder blocks 34 are defined by the second circumferential main groove 16 and the second lug groove 32.

  In the shoulder block 34, a third lug groove 36 is formed in the central portion in the circumferential direction in parallel with the second lug groove 32. The end of the third lug groove 36 on the tire equatorial plane CL side terminates in the block without being connected to the second circumferential main groove 16, and the end on the outer side in the tire axial direction is the ground contact end. It is arranged on the outer side in the tire axial direction than 12E. In addition, a sipe 38 extending along the tire circumferential direction is formed on the shoulder block 34 on the second circumferential main groove side, and between the second lug groove 32 and the third lug groove 36, A sipe 40 extending in parallel with the third lug groove 36 is formed from the sipe 38 toward the outer side in the tire axial direction.

  In the present embodiment, the shoulder block 34 on the right side of the tire equatorial plane CL and the shoulder block 34 on the left side of the tire equatorial plane CL are in a point-symmetric relationship with respect to both the block outer shape and the groove shape.

  The total width of the intermediate block 24 in the tire axial direction (W1 × 2 in this embodiment) is the total width W0 of the entire land portion (in this embodiment, the total width of the center rib (W2) + the intermediate block 24 The total width (W1 × 2) + the total width (W3 × 2) of the shoulder block 34 is preferably set to 35 to 60%. The width W3 of the shoulder block 34 is a dimension measured along the tire axial direction from the end portion on the second circumferential main groove 16 side to the ground contact end 12E.

  Here, the ground contact edge 12E means that the pneumatic tire 10R is mounted on a standard rim defined in JATMA YEAR BOOK (2008 edition, Japan Automobile Tire Association Standard), and is the maximum size and ply rating applicable to JATMA YEAR BOOK. When the maximum load capacity is loaded with an internal pressure of 100% of the air pressure (maximum air pressure) corresponding to the load capacity (bold load in the internal pressure-load capacity correspondence table). When the TRA standard or ETRTO standard is applied in the place of use or manufacturing, each standard is followed.

3 is a plan view of the tread 12 of the pneumatic tire 10L for the left wheel, and FIG. 2B is a cross-sectional view of the tread 12 of the pneumatic tire 10L for the left wheel. Is symmetrical with respect to the vehicle width center line.
In addition, the “groove” formed in the tread in the present embodiment is one in which the groove width does not become zero at the time of ground contact, and “sipe” indicates that the groove width becomes zero at the time of ground contact.

(Function)
In the pneumatic tire 10R of the present embodiment, the center rib 18 and the shoulder block 34 are point-symmetric, and the right half pattern and the left half pattern of the tread 12 are substantially point-symmetrical. The intermediate block 24 arranged on both sides of the surface CL corresponds to the internal structure where one and the other are point-symmetrical with respect to the tire equatorial plane, and the groove shape in the block is asymmetrical left and right Since the relationship is asymmetric with respect to the point, the orientation (inner side and outer side) when the vehicle is mounted can be easily distinguished as compared with the case of perfect point symmetry.

  Further, since the center rib 18 on the center side in the width direction of the tread 12 and the shoulder block 34 on the shoulder side are point-symmetrical on the left and right sides of the tire equatorial plane CL, the tread as a whole has a substantially point-symmetric pattern. Therefore, the difference in performance between the left and right can be suppressed.

  Further, by setting the total width (W1 × 2) of the intermediate block 24 in the tire axial direction to 35 to 60% of the total width W0 of the entire land portion of the tread 12, the left and right intermediate blocks 24 are point-symmetrically related. Compared to the case, the difference in appearance can be clarified, and the performance difference between the left and right of the tread 12 can be suppressed to an unaffected range.

  If the total width (W1 × 2) in the tire axial direction of the intermediate block 24 is less than 35% of the total land width W0, the intermediate block 24 becomes too small, and the left and right intermediate blocks 24 have a point-symmetric relationship. Compared to the case, the difference in appearance becomes difficult to understand.

  On the other hand, if the total width (W1 × 2) of the intermediate block 24 in the tire axial direction exceeds 60% of the total width W0 of the entire land portion, the intermediate land portion becomes too large, and the effect of the left and right performance difference of the tread 12 is affected. Become prominent.

[Second Embodiment]
Next, a pneumatic tire according to a second embodiment of the present invention will be described with reference to FIG. In addition, this embodiment is a modification of 1st Embodiment, The same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 4, in the pneumatic tire 10L for the right wheel of the present embodiment, the shape of the center rib 18 and the intermediate block 24 is the same as that of the first embodiment, but the center rib 18 and the intermediate block 24 are the same. Is shifted outward in the vehicle width direction.

For this reason, the difference in appearance becomes clearer as compared with the first embodiment while suppressing the difference in performance between the left and right of the tread 12.
In addition, even if attached to the pneumatic tire for the left wheel, the positions of the center rib 18 and the intermediate block 24 are shifted outward in the vehicle width direction, as in the case of the right wheel.

[Other Embodiments]
In the above embodiment, the internal structure of the pneumatic tire is asymmetrical with or without the edge bands 50 and 52, but the physical properties, hardness, etc. of the rubber constituting the tread 12 are different on the left and right, or the tread 12 is cross-sectioned. The outer contour may be asymmetrical.
Further, the number of circumferential main grooves may be other than four, but 3 to 5 is preferable in order to make it easy to understand a complete point-symmetric pattern and a difference in appearance.

It is a top view of the tread of the pneumatic tire for right wheels concerning a 1st embodiment. (A) is sectional drawing of the tread of the pneumatic tire for right wheels, (B) is sectional drawing of the tread of the pneumatic tire for left wheels. It is a top view of the tread of the pneumatic tire for left wheels concerning a 1st embodiment. It is a top view of the tread of the pneumatic tire for right wheels concerning a 2nd embodiment.

Explanation of symbols

10R Pneumatic tire (for right wheel)
10L Pneumatic tire (for left wheel)
12 tread 14 first circumferential main groove 16 second circumferential main groove 18 center rib (land portion)
24 intermediate block (intermediate land)
34 Shoulder block (shoulder land)
CL tire equator

Claims (4)

A pneumatic tire in which at least one of the internal structure and the cross-sectional shape along the tire rotation axis is asymmetrical on the left and right of the tire equatorial plane, and the mounting direction is specified,
A plurality of circumferential main grooves formed in the tread;
A plurality of land portions provided in the tread and partitioned by the plurality of circumferential main grooves;
With
The outermost shoulder land portion in the tire axial direction on one side and the outermost shoulder land portion in the tire axial direction on the other side with respect to the tire equator plane are in a point-symmetric relationship,
The middle land portion on one side and the middle portion on the other side of the tire equator surface of the pair of left and right intermediate land portions arranged on the tire equator surface side of the shoulder land portion and on both sides of the tire equator surface A pneumatic tire that is not point-symmetric with the land.   2. The air according to claim 1, wherein the outer land of the intermediate land portion on one side and the intermediate land portion on the other side of the tire equator plane are point-symmetric and the groove shape in the land portion is asymmetric. Enter tire.   The pneumatic tire according to claim 1 or 2, wherein a total width of the intermediate land portion in the tire axial direction is 35 to 60% of a total width of the entire land portion of the tread.   The distance A from the intermediate land portion on one side of the tire equator plane to the tire equator plane is different from the distance B from the intermediate land portion on the other side of the tire equator plane to the tire equator plane. The pneumatic tire according to claim 3.

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