JP6411948B2 - tire - Google Patents

Description

  The present invention relates to a tire that suppresses uneven wear, and particularly relates to a tire that suppresses uneven wear of a shoulder land portion.

  In the pneumatic tires (hereinafter referred to as tires) that are mounted on passenger cars and the like, various techniques have been conventionally used in order to suppress uneven wear on the tread. As one form of uneven wear of the tread, shoulder uneven wear in which the shoulder land portion wears faster than the center land portion is known.

  In order to suppress such shoulder uneven wear, for example, a method of forming a pair of narrow grooves (lateral grooves) extending in the tire width direction in the shoulder land portion has been proposed (for example, Patent Document 1). Specifically, an outward lateral groove that opens to the circumferential groove on the outer side in the tire width direction and an inward lateral groove that opens to the circumferential groove on the inner side in the tire width direction are formed in the shoulder land portion. According to such a tire, since the deformation of the shoulder land portion can be reduced while eliminating the lateral groove defining the shoulder land portion, uneven wear (heel and toe wear) of the shoulder land portion is suppressed.

JP 2007-261296 A

  By the way, in recent years, vehicles with a negative camber set as the mainstream of domestically produced vehicles have become mainstream.

  In a vehicle in which a negative camber is set, particularly during straight traveling, a larger load is applied to the inner portion of the tire when the vehicle is mounted than to the outer portion of the vehicle. Accordingly, there is a problem that the shoulder uneven wear on the inner side is particularly prominent when the vehicle is mounted.

  Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a tire that can effectively suppress shoulder uneven wear even when the negative camber is attached to a vehicle. To do.

  A tire according to the present invention is a tire including a center land portion formed in a region including a tire equator line, and a shoulder land portion formed outside the center land portion in the tire width direction, and the shoulder land In the part, a plurality of width direction sipes and circumferential direction sipes are formed at a predetermined pitch in the tire circumferential direction, the width direction sipes extend in the tire width direction and terminate in the shoulder land portion, and the circumferential direction sipes are It is located on the tire equator line side with respect to the width direction sipe and extends in the tire circumferential direction, and terminates in the shoulder land portion, and the width direction sipe and the circumferential direction sipe are linear in a tread tread view, The width-direction sipe has a zigzag portion that is zigzag in the tire circumferential direction toward the inside in the tire radial direction.

  According to the characteristics of the present invention, it is possible to provide a tire that can effectively suppress uneven shoulder wear even when the negative camber is applied to a vehicle.

It is an expanded view of the tread pattern of the tire which concerns on embodiment of this invention. (A) is an arrow sectional view of the AA line of FIG. 1, (b) is an arrow sectional view of the BB line of FIG.

  Next, an embodiment of a tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  In the present embodiment, (1) the overall configuration of the tread portion, (2) the detailed configuration of the sipe, (3) actions and effects, (4) examples, and (5) other embodiments will be described.

(1) Overall Configuration of Tread Part A tire (pneumatic tire) 10 according to the present embodiment is a general radial tire including a bead part, a carcass layer, and a belt layer (not shown). The tire 10 may be filled with an inert gas such as nitrogen gas instead of air.

  As shown in FIG. 1, the tire 10 includes a tread portion 11 that contacts the road surface during traveling. The tread portion 11 is formed with a center main groove 12 extending in the tire circumferential direction on the tire equator line CL and a pair of shoulder main grooves 13 and 14 provided so as to sandwich the center main groove 12 and extending in the tire circumferential direction. Has been. The center land portions 15 and 16 and the shoulder land portions 17 and 18 are defined in the tread portion 11 by these circumferential grooves (the center main groove 12 and the pair of shoulder main grooves 13 and 14). The center land portions 15 and 16 are formed in a region including the tire equator line CL, and the shoulder land portions 17 and 18 are formed outside the center land portions 15 and 16 in the tire width direction.

  An outer sipe (hereinafter referred to as a width sipe) 19 and an inner sipe (hereinafter referred to as a circumferential sipe) 20 are formed on the shoulder land portion 17 located on the inner side IN when the vehicle is mounted. The width direction sipe 19 extends in the tire width direction and terminates in the shoulder land portion 17. The circumferential sipe 20 is located closer to the tire equator line CL than the widthwise sipe 19, extends in the tire circumferential direction, and terminates in the shoulder land portion 17. These width-direction sipes 19 and circumferential sipes 20 are alternately arranged at intervals in the tire circumferential direction and do not communicate with each other. On the other hand, the width direction sipe 19 and the circumferential direction sipe 20 are disposed so as to overlap in the tire width direction. A plurality of the width direction sipes 19 and the circumferential direction sipes 20 are arranged at a predetermined pitch (equal pitch in the present embodiment) LP in the tire circumferential direction. Here, when “pitch LP” is “equal pitch”, “pitch LP” means the distance between the center lines of sipes of the same type adjacent to each other in the tire circumferential direction, that is, the total circumferential length of the tire 10. Is divided by the total number of pitches of the same type of sipes.

  On the other hand, an outer sipe (hereinafter referred to as a first sipe) 21 and an inner sipe (hereinafter referred to as a second sipe) 22 are formed on the shoulder land portion 18 located on the outer side OUT when the vehicle is mounted. The first sipe 21 extends in the tire width direction and terminates in the shoulder land portion 18. The second sipe 22 is located closer to the tire equator line CL than the first sipe 21 and extends in the tire width direction, and the inner end in the tire width direction terminates in the shoulder land portion 18. The first sipe 21 and the second sipe 22 are alternately arranged at intervals in the tire circumferential direction and do not communicate with each other. On the other hand, the first sipe 21 and the second sipe 22 are arranged so as to overlap in the tire width direction. A plurality of first sipes 21 and second sipes 22 are arranged at a predetermined pitch (equal pitch in this embodiment) LP in the tire circumferential direction.

  In the present specification, “inner side when vehicle is mounted” means the inner side in the vehicle width direction, that is, the side closer to the center line of the vehicle across the tire equator line CL in the mounting posture to the vehicle. To do. Similarly, in this specification, “outside OUT when vehicle is mounted” means the outside in the vehicle width direction, that is, the side far from the center line of the vehicle across the tire equator line CL in the mounting posture to the vehicle. And

(2) Detailed configuration of sipe As described above, the width direction sipe 19 and the circumferential direction sipe 20 are formed in the shoulder land portion 17 located on the inner side IN when the vehicle is mounted. The width direction sipe 19 and the circumferential direction sipe 20 are linear when viewed from the tread surface.

  The outer end of the width direction sipe 19 in the tire width direction is located on the tire ground contact end TW. The tire width direction outer side end of the width direction sipe 19 may be located on the opposite side of the tire equator line CL with respect to the tire ground contact end TW, and the tire equator line CL is more than the tire ground contact end TW. It may be located on the side. Moreover, the width direction sipe 19 is comprised from the linear part 19a and the zigzag part 19b, as shown to FIG. 1 and FIG. 2 (a). The straight portion 19 a is linear in the tire radial direction from the tread surface 17 a of the shoulder land portion 17 to a predetermined depth of the width direction sipe 19. The zigzag portion 19b has a zigzag shape in the tire circumferential direction from the lower end of the linear portion 19a toward the inside in the tire radial direction.

The circumferential sipe 20 extends in the vicinity of the shoulder main groove 13 adjacent to the shoulder land portion 17 on the inner side IN when the vehicle is mounted, and is not opened in the shoulder main groove 13. Further, as shown in FIGS. 1 and 2B, the circumferential sipe 20 is linear in the tire radial direction from the tread surface 17 a of the shoulder land portion 17 to the bottom portion 20 b of the circumferential sipe 20. Further, the circumferential sipe 20 is disposed so as to be separated from the shoulder main groove 13 by a distance of about 10% to 30% of the width W _SHO of the shoulder land portion 17 from the tire ground contact edge TW to the shoulder main groove 13. Has been.

  The length in the tire circumferential direction (groove width) of the width direction sipe 19 and the length (groove width) in the tire width direction of the circumferential direction sipe 20 are about 0.5 mm, and are center main grooves that are circumferential grooves. 12 and the pair of shoulder main grooves 13 and 14 are sufficiently smaller than the groove width. Further, the length (depth) from the tread surface 17a of the shoulder land portion 17 to the bottom portion 19c of the width direction sipe 19 and the length (depth) from the tread surface 17a of the shoulder land portion 17 to the bottom portion 20b of the circumferential sipe 20 Are approximately the same length.

  The width direction sipe 19 is disposed to be inclined with respect to the tire width direction, and the circumferential direction sipe 20 is disposed to be parallel to the tire circumferential direction. Specifically, the width direction sipe 19 is disposed at an inclination angle of 10 ° with respect to the tire width direction, and the circumferential direction sipe 20 is disposed at an inclination angle of 0 ° with respect to the tire circumferential direction. Yes. The width direction sipe 19 is inclined and arranged in a range of 0 ° to 30 ° with respect to the tire width direction, and the circumferential sipe 20 is arranged to be inclined in a range of 0 ° to 20 ° with respect to the tire circumferential direction. Preferably it is done.

The width W _S1 (see FIG. 1) of the width sipe 19 in the tire width direction is a range that does not reach the shoulder main groove 13, and the length L _S2 (see FIG. 1) of the circumferential sipe 20 in the tire circumferential direction. Big in comparison. In other words, the length L _S2 of the circumferential sipe 20 is smaller than the width W _S1 of the width sipe 19. The width W _SHO of the shoulder land portion 17 in the tire width direction and the width W _S1 of the width direction sipe 19 satisfy the relationship of 0.834 ≦ width W _S1 / width W _SHO ≦ 0.905, and the tire circumference L and the total length of the length L _S2 of the circumferential sipe 20 preferably satisfy the relationship of 0.500 ≦ total length of length L _S2 / tire circumferential length L ≦ 0.600. The “width W _S1 of the width direction sipe 19 in the tire width direction” is a width along a direction parallel to the tire width direction. Similarly, “the length L _S2 of the circumferential sipe 20 in the tire circumferential direction” is a length along a direction parallel to the tire circumferential direction, and “the total length of the length L _S2 of the circumferential sipe 20”. Is the sum of the lengths L _S2 of all the circumferential sipes 20 arranged in the tire circumferential direction. Further, the “tire circumference L” refers to a circumference measured in a region of the tire 10 where the circumferential sipe 20 is disposed.

  The position of the tire ground contact edge TW is determined based on the measurement conditions defined by JATMA in the tire 10 assembled on a standard size wheel rim (regular rim wheel) defined by the Japan Automobile Tire Association (JATMA) Year Book. (Applied to the applicable rim, specified internal pressure setting, set temperature, etc.) Note that other standards (TRA, ETRTO, etc.) may be used instead of JATMA. Further, in this specification, “linear” includes not only a perfect straight line but also a curve having a gentle curvature.

(3) Action / Effect In the tire 10 according to the present embodiment, the shoulder land portion 17 is formed with a plurality of the width direction sipes 19 and the circumferential direction sipes 20 at an equal pitch LP in the tire circumferential direction. The width direction sipe 19 extends in the tire width direction and terminates in the shoulder land portion 17, and the circumferential direction sipe 20 is located on the tire equator line CL side with respect to the width direction sipe 19, and extends in the tire circumferential direction. It terminates in the shoulder land portion 17. The width direction sipe 19 and the circumferential direction sipe 20 are linear when viewed from the tread surface, and the width direction sipe 19 has a zigzag portion 19b that is zigzag in the tire circumferential direction toward the inner side in the tire radial direction.

  When the width direction sipe 19 is not formed at all in the shoulder land portion 17, the difference in rigidity between the center land portions 15 and 16 and the shoulder land portion 17 becomes large. One of them may wear intensively (uneven wear). For this reason, in the tire 10 that can be used in a general load region, the shoulder land portion 17 from the viewpoint of suppressing uneven wear, the edge effect (the traction effect caused by the edge portion scratching the road surface), and the water film removing effect. Preferably has a widthwise sipe 19 (or a widthwise groove).

  When the tire 10 is attached to the vehicle with a negative camber attached, the load is concentrated on the shoulder land portion 17 on the inner side IN of the tire 10 when the vehicle is installed, particularly when traveling straight ahead. For this reason, when the shoulder land portion 17 has the width direction sipe 19 as in the tire 10, the block collapse in the tire circumferential direction tends to occur particularly in the shoulder land portion 17 on the inner side IN when the vehicle is mounted on the tire 10. is there. If the block collapses in the tire circumferential direction, uneven wear (heel and toe wear) of the shoulder land portion 17 on the inner side IN when the vehicle is mounted on the tire 10 may occur.

  Therefore, in the tire 10 according to the present embodiment, the width direction sipe 19 having the zigzag portion 19b is formed in the shoulder land portion 17 in order to suppress the block collapse in the circumferential direction.

However, if the width W _S1 of the width direction sipe 19 in the tire width direction is too large, the shoulder land portion 17 becomes easy to move individually like a block partitioned in the tire circumferential direction by the width direction sipe 19 and moves in the tire circumferential direction. Since the continuity of the tire cannot be maintained, the collapse of the block in the tire circumferential direction tends to occur on the contrary. Moreover, since the nonuniformity of the rigidity distribution in the tire circumferential direction increases, there is a risk that uneven wear (heel and toe wear) of the shoulder land portion 17 is likely to occur. On the other hand, if the width W _S1 in the width direction sipes 19 in tire width direction is too small, the difference in stiffness between the area and without a region of the width direction sipes 19 occur, uneven wear of the shoulder land portion 17 due to the difference in rigidity is There are concerns that arise.

  Therefore, in the tire 10 according to the present embodiment, in order to adjust the rigidity balance in the tire width direction while maintaining the continuity of the shoulder land portion 17 in the tire circumferential direction, it is more than the width direction sipe 19 in the shoulder land portion 17. A circumferential sipe 20 is formed in a portion on the tire equator line CL side.

  Thus, by forming the width direction sipe 19 and the circumferential direction sipe 20 on the shoulder land portion 17, the occurrence of block collapse in the tire circumferential direction can be effectively suppressed, and the tire 10 provides a negative camber. Even when it is mounted on the vehicle in a state where it has been applied, it is possible to effectively suppress uneven shoulder wear.

  As described above, when the tire 10 is mounted on the vehicle with the negative camber applied, the load is concentrated on the shoulder land portion 17 on the inner side IN when the vehicle is mounted, particularly when traveling straight. And if the shoulder land part 17 has the circumferential sipe 20 like the tire 10, the edge component of a tire circumferential direction will increase, and it will become easy to generate | occur | produce a lateral force. For this reason, the cornering force (CF) rises in a region where the slip angle (SA) is small, and the steering response at a small steering angle is improved.

  That is, since the sipe formed on the shoulder equator line CL side of the shoulder land portion 17 on the tire equator line CL side is the circumferential sipe 20, a lateral force is generated in the shoulder land portion 17 even with a smaller minute steering angle. Therefore, it is possible to effectively improve the steering response at a small steering angle.

  Further, since the width direction sipe 19 and the circumferential direction sipe 20 are linear when viewed from the tread surface, road noise is compared with the case where the width direction sipe 19 and the circumferential direction sipe 20 are zigzag when viewed from the tread surface. Can be reduced.

  Further, in the tire 10 according to the present embodiment, the width-direction sipe 19 and the circumferential-direction sipe 20 are formed on the shoulder land portion 17 located on the inner side IN when the vehicle is mounted. In this way, when the tire 10 is mounted on the vehicle with a negative camber applied, the shoulder uneven wear on the inner side IN is particularly prominent when the vehicle is mounted. Can effectively suppress uneven shoulder wear.

  Further, in the tire 10 according to the present embodiment, the width-direction sipe 19 and the circumferential-direction sipe 20 are alternately arranged at intervals in the tire circumferential direction. By doing in this way, since the rigidity balance of the tire circumferential direction in the shoulder land part 17 becomes favorable, the uneven wear resistance of the shoulder land part 17 improves more.

  When the width direction sipe 19 and the circumferential direction sipe 20 are not alternately arranged at intervals in the tire circumferential direction, and the width direction sipe 19 and the circumferential direction sipe 20 are arranged adjacent to each other in the tire width direction. The strain direction and twist direction of a region where the width direction sipe 19 is substantially constant, and there is a concern that cracks may occur between the width direction sipe 19 and the circumferential direction sipe 20. In particular, when the distance in the tire width direction between the width direction sipe 19 and the circumferential direction sipe 20 is too short, the shoulder land portion 18 behaves as if it is partitioned in the tire circumferential direction by the width direction sipe 19, and the width direction There is a risk that cracks are likely to occur between the sipe 19 and the circumferential sipe 20. For this reason, in the tire 10 according to the present embodiment, the width direction sipe 19 and the circumferential direction sipe 20 are spaced apart from each other in the tire circumferential direction from the viewpoint of suppressing the occurrence of cracks as well as the rigidity balance in the tire circumferential direction. They are arranged alternately.

  Further, in the tire 10 according to the present embodiment, the width direction sipe 19 and the circumferential direction sipe 20 are arranged so as to overlap in the tire width direction. By doing in this way, formation of the plain rib in the part in which these width direction sipes 19 and circumferential sipes 20 do not exist in the tire circumferential direction can be avoided. For this reason, it becomes possible to suppress shoulder uneven wear effectively by suppressing the rigidity of the plain rib portion higher than that of other portions and suppressing the locally increased rigidity.

  Further, in the tire 10 according to the present embodiment, the width direction sipe 19 is arranged to be inclined in a range of 0 ° to 30 ° with respect to the tire width direction, and the circumferential direction sipe 20 is directed to the tire circumferential direction. And inclined at a range of 0 ° to 20 °. By doing so, lateral force is not generated excessively due to excessive increase of the edge component acting in the tire width direction, and there is no possibility of hindering straight running performance. In particular, if the inclination angle of the width direction sipe 19 with respect to the tire width direction is too large, there is a concern that lateral force is excessively generated due to an excessive increase in the edge component in the tire circumferential direction and hinders straight running performance. On the other hand, when the inclination angle of the circumferential sipe 20 with respect to the tire circumferential direction is too large, there is a concern that the edge component acting in the tire width direction is insufficient and the cornering force is not sufficiently generated.

By the way, if the length L _S2 of the circumferential sipe 20 in the tire circumferential direction is too large, block collapse in the tire width direction is likely to occur during cornering of the vehicle. In this case, since the edge effect cannot be obtained, the cornering force rises in an area where the slip angle is small, and the steering response at a small steering angle may be deteriorated. Further, when the vehicle is cornered, the block collapses in the tire width direction, and not the tread surface but the side surface of the shoulder land portion 17 comes into contact with the ground, and the side surface wear progresses, so that there is a possibility that the rigidity is locally reduced. On the other hand, if the length L _S2 of the circumferential sipe 20 in the tire circumferential direction is too small, the edge component in the tire circumferential direction becomes insufficient, and there is a concern that cornering force is not sufficiently generated.

Therefore, in the tire 10 according to the present embodiment, the width W _SHO of the shoulder land portion 17 in the tire width direction and the width W _S1 of the width direction sipe 19 are 0.834 ≦ width W _S1 / width W _SHO ≦ 0. 905, and the total length of the tire circumferential length and the length L _S2 of the circumferential sipe 20 in the tire circumferential direction is 0.500 ≦ total length of length L _S2 / tire circumferential length L ≦ 0.600 It is configured to satisfy the relationship. By setting the width W _S1 of the width direction sipe 19 within the above-mentioned numerical range, the rigidity balance in the tire width direction in the shoulder land portion 17 becomes good, so the uneven wear resistance of the shoulder land portion 17 is further improved. To do. Further, the steering response is improved by setting the length L _S2 of the circumferential sipe 20 within the above numerical range.

(4) Examples Next, in order to clarify the effects of the present invention, results of tests performed using tires according to Examples 1 to 3 and Comparative Examples 1 to 3 will be described. In addition, this invention is not limited at all by these examples.

  In this test, all tire sizes and pattern design factors were the same. Here, in this test, the size of all tires was set to “155 / 65R14”.

  Here, as Comparative Example 1, a tire in which the width direction sipe 19 is configured only by the straight line portion 19a was used. Further, as Comparative Example 2, a tire in which the width-direction sipe 19 is configured to penetrate through the shoulder main groove 13 and the circumferential sipe 20 is not formed in the shoulder land portion 17 is used. Furthermore, as Comparative Example 3, a tire configured such that the width of the width-direction sipe 19 with respect to the tire width direction and the width of the circumferential-direction sipe 20 with respect to the tire circumferential direction is smaller than those in Examples 1-3. .

Table 1 shows the results of this test. Evaluation results of the steering responsiveness and wear life was indicated by an index, the larger the index, has excellent steering responsiveness and wear life.

From the results shown in Table 1, it was found that the tires according to Examples 1 to 3 can improve the wear life compared to the tires according to Comparative Examples 1 to 3. Furthermore, it was found that the tires according to Examples 1 and 3 can improve both the steering response and the wear life .

(5) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows.

  In the tire 10 in the above-described embodiment, the circumferential sipe 20 is composed of the straight portion 20a. However, the present invention is not limited thereto, and the zigzag portion that is zigzag in the tire width direction toward the inner side in the tire radial direction. But you can. Moreover, although the tire 10 in the above-mentioned embodiment was a radial tire, it is not limited thereto, and may be a solid tire formed entirely of rubber, for example. Furthermore, in the tire 10 in the above-described embodiment, the width direction sipe 19 and the circumferential direction sipe 20 are plurally formed at equal pitches in the tire circumferential direction. The sipe intervals may be formed at unequal pitches that are not equal.

DESCRIPTION OF SYMBOLS 10 Tire 11 Tread part 15 Center land part 16 Center land part 17 Shoulder land part 18 Shoulder land part 19 Outer sipe (width direction sipe)
19b Zigzag portion 20 Inner sipe (circumferential sipe)
CL tire equator line LP pitch

Claims (5)

A center land portion formed in a region including the tire equator line,
A tire comprising a shoulder land portion formed on the outer side in the tire width direction than the center land portion,
In the shoulder land portion, a plurality of width direction sipes and circumferential direction sipes are formed at a predetermined pitch in the tire circumferential direction,
The width sipe extends in the tire width direction and terminates in the shoulder land portion,
The circumferential sipe is located closer to the tire equator than the width sipe, and extends in the tire circumferential direction, and terminates in the shoulder land portion.
The width direction sipe and the circumferential direction sipe are linear in a tread tread view,
The width direction sipes have a zig-zag portion is zigzag in the tire circumferential direction toward the inner side in the tire radial direction,
The width W _SHO of the shoulder land portion in the tire width direction and the width W _S1 of the width direction sipe satisfy the relationship of 0.834 ≦ width W _S1 / width W _SHO ≦ 0.905, and the tire circumference L and the total length of the circumferential sipe length L _S2 in the tire circumferential direction satisfy the relationship of 0.500 ≦ total length of length L _S2 / tire circumferential length L ≦ 0.600. A characteristic tire.   The tire according to claim 1, wherein the width-direction sipe and the circumferential-direction sipe are formed on the shoulder land portion located on the inner side when the vehicle is mounted.   The tire according to claim 1, wherein the width-direction sipe and the circumferential-direction sipe are alternately arranged at intervals in the tire circumferential direction.   The tire according to claim 1, wherein the width direction sipe and the circumferential direction sipe are arranged so as to overlap in the tire width direction.   The width direction sipe is disposed to be inclined in a range of 0 ° to 30 ° with respect to the tire width direction, and the circumferential sipe is inclined in a range of 0 ° to 20 ° with respect to the tire circumferential direction. The tire according to claim 1 arranged.

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