JP6374819B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire that can exhibit excellent steering stability.

  For example, the pneumatic tire disclosed in Patent Document 1 below has an outer tread end positioned on the vehicle outer side when the vehicle is mounted and an inner tread end positioned on the vehicle inner side when the vehicle is mounted, by specifying the mounting direction to the vehicle. A through sipe that crosses the entire width of the outer land portion in the tire axial direction is provided in the outer land portion on the outer tread end side of the tire equator. And the penetration sipe of patent document 1 contains the V-shaped part which becomes convex in a tire peripheral direction in tread plane view.

  In the through sipe including the V-shaped portion as described above, when a lateral force acts on the outer land portion during turning, the sipe walls facing each other closely contact each other. For this reason, the outer land portion provided with the penetrating sipe has increased apparent rigidity and has a behavior similar to that of a rib continuous in the tire circumferential direction. In particular, when the sipe walls are in close contact with each other, the rigidity in the vicinity of the top of the V-shaped portion is most enhanced.

  However, in the pneumatic tire of Patent Document 1, the top of the V-shaped portion of the penetrating sipe is provided on the tire equator side with respect to the center position in the width direction of the outer land portion. Such arrangement of the top of the V-shaped portion tends to lower the rigidity on the outer tread end side of the outer land portion than that on the tire equator side. For this reason, the pneumatic tire of Patent Document 1 has a tendency that the outer tread end side of the outer land portion is likely to be deformed, for example, at the time of turning, and there is room for further improvement in improving the steering stability.

JP 2014-210499A

  The present invention has been devised in view of the above circumstances, and is based on improving the position of the top of the V-shaped portion of the through sipe, and a pneumatic tire capable of exhibiting excellent steering stability. The main purpose is to provide.

  The present invention is a pneumatic tire having an outer tread end positioned outside the vehicle when the vehicle is mounted and an inner tread end positioned inside the vehicle when the vehicle is mounted. The tread portion is provided with a plurality of main grooves extending continuously in the tire circumferential direction and a land portion divided into the main grooves, and the land portion is disposed on the outer tread end side of the tire equator. The outer land portion is provided with a through sipe that crosses the entire width of the outer land portion, and the through sipe is a first inclined portion that is inclined with respect to the tire axial direction in a tread plan view. And a V-shaped portion continuous with a second inclined portion inclined in the opposite direction to the first inclined portion, and the top of the V-shaped portion is more than the center position in the width direction of the outer land portion. Provided on the outer tread edge It is characterized in.

  In the pneumatic tire of the present invention, the main groove includes a center main groove provided on the tire equator, and an outer shoulder main groove provided between the center main groove and the outer tread end, The outer land portion preferably includes an outer middle land portion between the center main groove and the outer shoulder main groove, and the outer middle land portion is preferably provided with the penetrating sipe.

  In the pneumatic tire of the present invention, it is desirable that the outer middle land portion is provided with an outer middle lug sipe extending from the outer shoulder main groove and terminating in the outer middle land portion.

  In the pneumatic tire of the present invention, it is preferable that the outer middle lag sipe includes a portion extending along the V-shaped portion of the penetrating sipe.

  In the pneumatic tire of the present invention, the land portion includes an outer shoulder land portion between the outer shoulder main groove and the outer tread end, and one end of the outer shoulder land portion is formed in the outer shoulder main groove. It is desirable that an outer shoulder sipe that communicates is provided, and the outer shoulder sipe is smoothly continuous with the outer middle lug sipe and the outer shoulder main groove.

  In the pneumatic tire of the present invention, the main groove includes an inner shoulder main groove between the center main groove and the inner tread end, and the land portion includes the center main groove and the inner shoulder main groove. An inner middle sipe across the entire width of the inner middle land portion, and the inner middle sipe includes the penetrating sipe provided in the outer middle land portion. It is desirable that it is continuous smoothly through the center main groove.

  In the pneumatic tire of the present invention, the land portion includes an inner shoulder land portion between the inner shoulder main groove and the inner tread end, and one end of the inner shoulder land portion is formed in the inner shoulder main groove. It is preferable that an inner shoulder sipe that communicates is provided, and the inner shoulder sipe is smoothly continuous with the inner middle sipe via the inner shoulder main groove.

  The pneumatic tire of the present invention includes an outer land portion disposed on the outer tread end side of the tire equator. The outer land portion is provided with a penetrating sipe across the entire width of the outer land portion. The through sipe includes a V-shaped portion in which a first inclined portion inclined with respect to the tire axial direction and a second inclined portion inclined in the direction opposite to the first inclined portion are continuous in a tread plan view. .

  In the penetrating sipe having such a V-shaped part, when a lateral force acts on the land portion, the sipe walls facing each other are in close contact with each other. For this reason, the apparent rigidity of the outer land portion is increased, and as a result, the steering stability is improved.

  The top of the V-shaped portion of the penetrating sipe is provided on the outer tread end side with respect to the center position in the width direction of the outer land portion. As a result, the rigidity of the outer land portion on the outer tread end side is higher than the rigidity of the outer land portion on the tire equator side. For this reason, even when the ground pressure on the outer tread end side of the outer land portion increases during turning, excessive deformation of the outer land portion is suppressed. Therefore, excellent steering stability is exhibited.

It is an expanded view of the tread part of the pneumatic tire of one embodiment of the present invention. It is an enlarged view of the outer middle land part of FIG. (A) is the sectional view on the AA line of the 1st inclination part of FIG. 2, (b) is the BB sectional view of the 2nd inclination part of FIG. It is an enlarged view of the inner middle land part of FIG. It is an enlarged view of the outer side shoulder land part of FIG. It is an enlarged view of the inner side shoulder land part of FIG. It is an enlarged view of the tread part of the pneumatic tire of a comparative example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a development view of a tread portion 2 of a pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 of the present embodiment. The pneumatic tire 1 of this embodiment is suitably used for, for example, a passenger car.

  The tread portion 2 of the present embodiment includes, for example, a tread pattern in which the mounting direction to the vehicle is specified. The direction of mounting on the vehicle is displayed by, for example, characters or marks on a sidewall (not shown) or the like. In FIG. 1, the left side corresponds to the vehicle outer side, and the right side corresponds to the vehicle inner side.

  By specifying the direction of mounting on the vehicle, the tread portion 2 has an outer tread end Te1 positioned on the vehicle outer side when the vehicle is mounted and an inner tread end Te2 positioned on the vehicle inner side when the vehicle is mounted. .

  Each of the tread ends Te1 and Te2 is a flat surface with a normal load applied to a normal tire 1 which is assembled with a normal rim (not shown) and filled with a normal internal pressure and is not loaded, and a camber angle of 0 °. This is the contact position on the outermost side in the tire axial direction when the contact is made on the ground.

  The “regular rim” is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, For ETRTO, "Measuring Rim".

  “Regular internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. The maximum value described in “VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” for ETRTO.

  “Regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. “JATMA” is “Maximum load capacity”, TRA is “TIRE LOAD LIMITS” The maximum value described in “AT VARIOUS COLD INFLATION PRESSURES”, “LOAD CAPACITY” in the case of ETRTO.

  The tread portion 2 of the tire 1 is provided with a plurality of main grooves 3 extending continuously in the tire circumferential direction and land portions 4 divided into the main grooves 3.

  Each main groove 3 extends linearly in the tire circumferential direction, for example. Each main groove 3 may extend in, for example, a zigzag shape or a wave shape.

  The main groove 3 includes, for example, a shoulder main groove 5 provided on the outer tread end Te1 side or the inner tread end Te2 side, and a center main groove 6 provided on the tire equator C side with respect to the shoulder main groove 5. Yes.

  The shoulder main groove 5 includes, for example, an outer shoulder main groove 5A provided on the outer tread end Te1 side and an inner shoulder main groove 5B provided on the inner tread end Te2 side.

  The center main groove 6 is provided between the outer shoulder main groove 5A and the inner shoulder main groove 5B, for example. One center main groove 6 of this embodiment is provided on the tire equator C, for example. For example, one center main groove 6 may be provided on each of the outer tread end Te1 side and the inner tread end Te2 side of the tire equator C.

  The groove width W1 of each of the shoulder main grooves 5A and 5B and the groove width W2 of the center main groove 6 in the present embodiment are desirably 3.5 to 10.0% of the tread ground contact width TW, for example. In the case of a pneumatic tire for a passenger car, the groove depth of the shoulder main groove 5 and the groove depth (not shown) of the center main groove 6 are preferably 5.0 to 12.0 mm, for example. The tread contact width TW is a distance in the tire axial direction between the outer tread end Te1 and the inner tread end Te2 of the tire 1 in the normal state.

  The inner shoulder main groove 5B of the present embodiment has a larger groove width than the outer shoulder main groove 5A, for example. Thereby, the steering stability and wet performance on a dry road surface are improved with a good balance.

  The center main groove 6 of this embodiment has a larger groove width than the inner shoulder main groove 5B, for example. This makes it easy for water near the tire equator C to be discharged during wet running, and the hydroplaning phenomenon is effectively suppressed.

  By providing the main groove 3 described above, the land portion 4 includes, for example, a middle land portion 7 between the shoulder main groove 5 and the center main groove 6 and a shoulder land portion on the outer side in the tire axial direction of the shoulder main groove 5. 8 is divided.

  The middle land portion 7 includes, for example, an outer middle land portion 7A between the outer shoulder main groove 5A and the center main groove 6 and an inner middle land portion 7B between the inner shoulder main groove 5B and the center main groove 6. Contains. The shoulder land portion includes, for example, an outer shoulder land portion 8A between the outer shoulder main groove 5A and the outer tread end Te1, and an inner shoulder land portion 8B between the inner shoulder main groove 5B and the inner tread end Te2. It is out.

  The land portion 4 is divided into an outer land portion 4A arranged on the outer tread end Te1 side from the tire equator C and an inner land portion 4B arranged on the inner tread end Te2 side from the tire equator C. . The outer land portion 4A of the present embodiment includes an outer middle land portion 7A and an outer shoulder land portion 8A. The inner land portion 4B of the present embodiment includes an inner middle land portion 7B and an inner shoulder land portion 8B.

  FIG. 2 shows an enlarged view of the outer middle land portion 7A. As shown in FIG. 2, the outer middle land portion 7A is provided with a penetrating sipe 10 across the entire width of the land portion. In this specification, “sipe” means a cut having a main part width of 1.5 mm or less, and includes an aspect having an opening having a width exceeding 1.5 mm on the tread surface side of the land part.

  The penetrating sipe 10 includes a first inclined portion 11 and a second inclined portion 12 in a tread plan view.

  The first inclined portion 11 is inclined with respect to the tire axial direction. The first inclined portion 11 of the present embodiment is inclined, for example, from the center main groove 6 to one side in the tire circumferential direction (upper side in FIG. 2) and extends linearly.

  An angle θ1 of the first inclined portion 11 with respect to the tire axial direction is, for example, 20 to 30 °. Such a 1st inclination part 11 can exhibit the frictional force by an edge with sufficient balance with respect to a tire peripheral direction and a tire axial direction.

  FIG. 3A shows a cross-sectional view taken along line AA of the first inclined portion 11. As shown in FIG. 3A, the first inclined portion 11 has, for example, a certain width from the tread surface 2s of the land portion to the bottom portion.

  As shown in FIG. 2, the second inclined portion 12 is disposed, for example, on the outer tread end Te <b> 1 side (shown in FIG. 1, the same applies hereinafter) with respect to the first inclined portion 11. The second inclined portion 12 is inclined in the opposite direction to the first inclined portion 11. The second inclined portion 12 of the present embodiment is inclined, for example, from the outer shoulder main groove 5A to one side in the tire circumferential direction and extends linearly.

  For example, the angle θ2 of the second inclined portion 12 with respect to the tire axial direction is preferably smaller than the angle θ1 of the first inclined portion 11 with respect to the tire axial direction. Specifically, the angle θ2 of the second inclined portion 12 with respect to the tire axial direction is, for example, 18 to 25 °.

  FIG. 3B shows a cross-sectional view taken along line BB of the second inclined portion 12 of FIG. As shown in FIG. 3B, the second inclined portion 12 includes, for example, a main body portion 16 extending with a certain width, and an opening portion 17 having an enlarged width between the main body portion 16 and the tread surface 2s of the land portion. Including. Such a 2nd inclination part 12 is useful for improving wet performance.

  As shown in FIG. 2, the penetrating sipe 10 includes a V-shaped portion 14 in which the first inclined portion 11 and the second inclined portion 12 are continuous in the tread plan view. In the penetrating sipe 10 having such a V-shaped portion 14, when a lateral force acts on the land portion, the sipe walls facing each other are in close contact with each other. For this reason, the apparent rigidity of the outer middle land portion 7A is increased, and as a result, the steering stability is improved.

  As a more desirable aspect, the penetration sipe 10 of this embodiment is formed in a V shape as a whole. Thereby, since the whole sipe wall mutually adheres, steering stability is improved further. However, the penetrating sipe 10 is not limited to such a mode, and it is only necessary to partially include the V-shaped portion 14.

  The top portion 18 of the V-shaped portion 14 of the penetrating sipe 10 is provided on the outer tread end Te1 side with respect to the center position 20 in the width direction of the outer middle land portion 7A. Accordingly, the rigidity of the outer middle land portion 7A on the outer tread end Te1 side is higher than the rigidity of the outer middle land portion 7A on the tire equator C side. Thereby, even when the ground pressure or lateral force on the outer tread end Te1 side of the outer middle land portion 7A increases during turning, excessive deformation of the outer middle land portion 7A is suppressed. Therefore, excellent steering stability is exhibited.

  In order to further exert the above-described effects, the distance L1 in the tire axial direction from the top 18 to the center main groove 6 is preferably 0.60 times or more the width W3 in the tire axial direction of the outer middle land portion 7A. Preferably it is 0.65 times or more, preferably 0.80 times or less, more preferably 0.75 times or less.

  In order to suppress uneven wear in the vicinity of the top portion 18, it is desirable that the angle θ3 between the first inclined portion 11 and the second inclined portion 12 is an obtuse angle. Specifically, the angle θ3 is preferably 125 ° or more, more preferably 130 ° or more, preferably 140 ° or less, more preferably 135 ° or less. Thereby, the above-mentioned effect is exhibited while suppressing uneven wear near the top 18.

  If the above-mentioned penetration sipe 10 is provided in 4 A of outer land parts (shown in FIG. 1), the above-mentioned effect can be exhibited. For this reason, the penetration sipe 10 may be provided in the outer shoulder land portion 8A (shown in FIG. 1), for example.

  As a desirable mode, the outer middle land portion 7A of the present embodiment is provided with, for example, an outer middle lug sipe 24 extending from the outer shoulder main groove 5A and terminating in the outer middle land portion 7A. The penetration sipe 10 and the outer middle lag sipe 24 described above are alternately provided in the tire circumferential direction.

  The outer middle lag sipe 24 includes, for example, a third inclined portion 25 and a fourth inclined portion 26.

  The third inclined portion 25 extends from the inner end 24 i of the outer middle lug sipe 24 in the tire axial direction in the same direction as the first inclined portion 11 of the through sipe 10. The 3rd inclination part 25 of this embodiment is extended along the 1st inclination part 11, for example.

  The third inclined portion 25 of the present embodiment has, for example, the same configuration as the cross-sectional shape of the first inclined portion 11 (shown in FIG. 3A and hereinafter the same). That is, it is desirable that the third inclined portion 25 is formed with a constant width from the tread surface to the bottom portion of the land portion (not shown).

  For example, the fourth inclined portion 26 is disposed between the third inclined portion 25 and the outer shoulder main groove 5A. The fourth inclined portion 26 is inclined in the opposite direction to the third inclined portion 25. As a desirable mode, the 4th inclined part 26 of this embodiment has extended along the 2nd inclined part 12 of penetration sipe 10, for example.

  For example, the fourth inclined portion 26 has the same configuration as the cross-sectional shape of the second inclined portion 12 of the penetrating sipe 10 (shown in FIG. 3B and the same applies hereinafter). That is, the 4th inclination part 26 contains the main-body part extended with a fixed width | variety, and the opening part which the width | variety expanded between the main-body part and the tread of a land part (illustration omitted), for example. Such a 4th inclination part 26 is useful for improving wet performance.

  The outer middle lag sipe 24 includes a portion extending along the V-shaped portion 14 of the penetrating sipe 10 by connecting the third inclined portion 25 and the fourth inclined portion 26 described above. As a desirable mode, the outer middle lag sipe 24 of the present embodiment is V-shaped as a whole. In such an outer middle lag sipe 24, when a lateral force acts on the land portion, the sipe walls facing each other are in close contact with each other, and the apparent rigidity of the outer middle land portion 7A can be further increased.

  FIG. 4 shows an enlarged view of the inner middle land portion 7B. As shown in FIG. 4, the inner middle land portion 7 </ b> B is provided with a plurality of inner middle sipes 28.

  The inner middle sipe 28 includes, for example, a central inclined portion 30 and first and second side portions 31 and 32 provided on both sides of the central inclined portion 30 in the tire axial direction.

  For example, the central inclined portion 30 is inclined with respect to the tire axial direction and extends linearly. Such a central inclined portion 30 exhibits an edge effect in the tire circumferential direction and the tire axial direction.

  The central inclined portion 30 is preferably inclined in the direction opposite to the first inclined portion 11 (shown in FIG. 1) of the through sipe 10, for example. Such a central inclined portion 30 is useful for suppressing a single flow of the tire.

  The angle θ4 of the central inclined portion 30 with respect to the tire axial direction is preferably 40 ° or more, more preferably 45 ° or more, preferably 55 ° or less, more preferably 50 ° or less. Such a central inclined portion 30 exhibits an edge effect with a good balance in the tire circumferential direction and the tire axial direction.

  For example, the central inclined portion 30 of the present embodiment has the same cross-sectional shape as the first inclined portion 11. That is, it is desirable that the central inclined portion 30 is formed with a certain width from the tread surface to the bottom of the land portion (not shown). In such a central inclined portion 30, sipe wall surfaces facing each other are in close contact with each other at the time of grounding. For this reason, the apparent rigidity of the inner middle land portion 7B is increased, and excellent steering stability is obtained.

  For example, the first side portion 31 communicates between the center main groove 6 and the central inclined portion 30. For example, the second side portion 32 communicates between the inner shoulder main groove 5 </ b> B and the central inclined portion 30.

  It is desirable that the first side portion 31 and the second side portion 32 each extend along the tire axial direction. As a result, uneven wear near the end of the inner middle sipe 28 is suppressed.

  It is desirable that the first side portion 31 and the second side portion 32 each have the same cross-sectional shape as the second inclined portion 12 of the penetrating sipe 10. That is, the first side portion 31 and the second side portion 32 include, for example, a main body portion extending with a constant width and an opening portion having an enlarged width between the main body portion and the tread surface of the land portion (illustrated). (Omitted). Such first side portion 31 and second side portion 32 are useful for improving wet performance.

  As shown in FIG. 1, it is desirable that the inner middle sipe 28 is smoothly continuous with the penetrating sipe 10 provided in the outer middle land portion 7 </ b> A via the center main groove 6. “Each sipe is smoothly continuous through the main groove” means that virtual sipes obtained by virtually extending each sipe intersect in the main groove. Such a sipe arrangement is useful for approximating the rigidity distribution in the tire circumferential direction between the outer middle land portion 7A and the inner middle land portion 7B, for example, to make the response of the steering wheel at the beginning of turning linear.

  FIG. 5 shows an enlarged view of the outer shoulder land portion 8A. As shown in FIG. 5, the outer shoulder land portion 8A is provided with, for example, outer shoulder lateral grooves 34 and outer shoulder sipes 35 alternately in the tire circumferential direction.

  The outer shoulder lateral groove 34 extends, for example, from the outer tread end Te1 to the tire equator C side and terminates in the outer shoulder land portion 8A. As a result, the rigidity of the outer shoulder land portion 8A on the inner side in the tire axial direction is increased, and excellent steering stability on a dry road surface can be obtained. In addition, such outer shoulder lateral grooves 34 are useful for reducing pumping noise because air does not flow from the outer shoulder main grooves 5A.

  It is desirable that the angle θ5 of the outer shoulder lateral groove 34 with respect to the tire axial direction gradually increases, for example, toward the inner side in the tire axial direction. Such outer shoulder lateral grooves 34 can effectively guide water in the grooves to the outer tread end Te1 side during wet running.

  The outer shoulder sipe 35 extends, for example, from the outer shoulder main groove 5A outward in the tire axial direction, and terminates in the outer shoulder land portion 8A.

  The outer shoulder sipe 35 includes, for example, an inner part 36 and an outer part 37.

  For example, the inner portion 36 communicates with the outer shoulder main groove 5A and extends along the tire axial direction. Such an inner part 36 can suppress the distortion of the ground contact surface between the inner end of the outer shoulder lateral groove 34 and the outer shoulder main groove 5A, and thus can suppress the uneven wear.

  For example, the inner portion 36 preferably has a cross-sectional shape similar to that of the second inclined portion 12. That is, the inner side portion 36 includes, for example, a main body portion extending with a constant width and an opening portion whose width is increased between the main body portion and the tread surface of the land portion (not shown). Such an inner portion 36 helps to improve wet performance.

  The outer side part 37 continues to the tire axial direction outer side of the inner side part 36, for example. The outer portion 37 terminates in the outer shoulder land portion 8A, for example, without reaching the outer tread end Te1.

  The outer portion 37 preferably has a cross-sectional shape similar to that of the first inclined portion 11, for example. That is, the outer side portion 37 is formed with a constant width from the tread surface to the bottom portion of the land portion (not shown), for example. Such an outer portion 37 is useful for suppressing uneven wear near the outer end of the outer shoulder sipe 35.

  As shown in FIG. 1, it is desirable that the outer shoulder sipe 35 is smoothly continuous via the outer middle lag sipe 24 and the outer shoulder main groove 5A. Such a sipe arrangement helps to make the progress of wear on both edges of the outer shoulder main groove 5A uniform.

  FIG. 6 shows an enlarged view of the inner shoulder land portion 8B. As shown in FIG. 6, for example, inner shoulder lateral grooves 38 and inner shoulder sipes 39 are alternately provided in the tire circumferential direction in the inner shoulder land portion 8B.

  For example, the inner shoulder lateral groove 38 has the same configuration as the outer shoulder lateral groove 34 (shown in FIG. 5). That is, the inner shoulder lateral groove 38 extends, for example, from the inner tread end Te2 to the tire equator C side and ends in the inner shoulder land portion 8B.

  The inner shoulder sipe 39 includes, for example, an inner portion 40 and an outer portion 41 as with the outer shoulder sipe 35.

  For example, the inner portion 40 of the inner shoulder sipe 39 communicates with the inner shoulder main groove 5B and extends along the tire axial direction. Moreover, it is desirable that the inner portion 40 of the inner shoulder sipe 39 has, for example, the same cross-sectional shape as the second inclined portion 12. That is, the inner portion 40 of the inner shoulder sipe 39 includes, for example, a main body portion extending with a constant width and an opening portion whose width is increased between the main body portion and the tread surface of the land portion (not shown).

  The outer side portion 41 of the inner side shoulder sipe 39 is connected to the inner tread end Te2 side of the inner side portion 40, for example. It is desirable that the outer portion 41 of the inner shoulder sipe 39 extends, for example, to the inner tread end Te2. Such an inner shoulder sipe 39 serves to suppress distortion of the ground plane between the inner shoulder lateral grooves 38.

  For example, the outer side portion 41 of the inner side shoulder sipe 39 preferably has the same cross-sectional shape as the first inclined portion 11. That is, the outer portion 41 of the inner shoulder sipe 39 is formed with a constant width from the tread surface to the bottom portion of the land portion (not shown), for example.

  As shown in FIG. 1, it is desirable that the inner shoulder sipe 39 is smoothly continuous with the inner middle sipe 28 through the inner shoulder main groove 5B. Such a sipe arrangement is useful for making uniform the progress of wear on both side edges of the inner shoulder main groove 5B.

  Although the pneumatic tire of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and is implemented with various modifications.

A pneumatic tire of size 195 / 65R15 having the basic tread pattern of FIG. 1 was prototyped based on the specifications in Table 1. As a comparative example, as shown in FIG. 7, a pneumatic tire in which the top of the V-shaped portion provided in the outer middle land portion is provided on the tire equator side with respect to the center position in the width direction of the outer middle land portion. Was prototyped. Each test tire was tested for steering stability and wet performance. The common specifications and test methods for each test tire are as follows.
Wearing rim: 15 × 6J
Tire internal pressure: 230kPa
Test vehicle: displacement 2400cc, front-wheel drive vehicle Test tire mounting position: all wheels

<Steering stability>
The driving stability of the test vehicle when traveling on an asphalt circuit was evaluated by the driver's sensuality. A result is a score which makes a comparative example 100, and shows that steering stability is excellent, so that a numerical value is large.
<Wet performance>
The test vehicle traveled on an asphalt road surface with a radius of 100 m provided with a puddle having a depth of 5 mm and a length of 20 m, and the lateral acceleration (lateral G) of the front wheels was measured. The result is an average lateral G at a speed of 50 to 80 km / h, and is indicated by an index with the value of the comparative example being 100. It shows that wet performance is excellent, so that a numerical value is large.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the pneumatic tires of the examples exhibited excellent steering stability. Moreover, it was confirmed that the wet performance of the pneumatic tire of the example was maintained.

2 tread portion 3 main groove 4 land portion 4A outer land portion 10 penetrating sipe 11 first inclined portion 12 second inclined portion 14 V-shaped portion 18 top portion 20 center position Te1 outer tread end Te2 inner tread end

Claims (7)

A pneumatic tire having an outer tread end positioned on the vehicle outer side when the vehicle is mounted and an inner tread end positioned on the vehicle inner side when the vehicle is mounted, by specifying the mounting direction on the vehicle,
The tread portion is provided with a plurality of main grooves extending continuously in the tire circumferential direction, and a land portion divided into the main grooves,
The land portion includes an outer land portion disposed on the outer tread end side of the tire equator,
The outer land portion is provided with a penetrating sipe across the entire width of the outer land portion,
The through sipe includes a V-shaped portion in which a first inclined portion inclined with respect to a tire axial direction and a second inclined portion inclined in a direction opposite to the first inclined portion are continuous in a tread plan view,
The top of the V-shaped part is provided on the outer tread end side than the center position in the width direction of the outer land part ,
The main groove includes a center main groove provided on the tire equator, and an outer shoulder main groove provided between the center main groove and the outer tread end,
The outer land portion includes an outer middle land portion between the center main groove and the outer shoulder main groove,
The outer middle land portion is provided with the penetrating sipe,
The pneumatic tire according to claim 1, wherein the outer middle land portion is provided with an outer middle lug sipe extending from the outer shoulder main groove and terminating in the outer middle land portion .
The first inclined portion has a certain width from the tread of the land portion to the bottom,
2. The pneumatic tire according to claim 1, wherein the second inclined portion includes a main body portion extending with a constant width, and an opening having an enlarged width between the main body portion and the tread surface of the land portion .
The second inclined portion is disposed closer to the outer tread end side than the first inclined portion,
The pneumatic tire according to claim 1 or 2 , wherein an angle of the second inclined portion with respect to the tire axial direction is smaller than an angle of the first inclined portion with respect to the tire axial direction .
The pneumatic tire according to any one of claims 1 to 3, wherein the outer middle lag sipe includes a portion extending along the V-shaped portion of the penetrating sipe.
The land portion includes an outer shoulder land portion between the outer shoulder main groove and the outer tread end,
The outer shoulder land portion is provided with an outer shoulder sipe whose one end communicates with the outer shoulder main groove,
The pneumatic tire according to any one of claims 1 to 4, wherein the outer shoulder sipe is smoothly continuous via the outer middle lag sipe and the outer shoulder main groove.
The main groove includes an inner shoulder main groove between the center main groove and the inner tread end,
The land portion includes an inner middle land portion between the center main groove and the inner shoulder main groove,
The inner middle land portion is provided with an inner middle sipe across the entire width of the inner middle land portion,
The pneumatic tire according to any one of claims 1 to 5, wherein the inner middle sipe is smoothly continuous with the penetrating sipe provided in the outer middle land portion via the center main groove. The land portion includes an inner shoulder land portion between the inner shoulder main groove and the inner tread end,
The inner shoulder land portion is provided with an inner shoulder sipe whose one end communicates with the inner shoulder main groove,
The pneumatic tire according to claim 6, wherein the inner shoulder sipe is smoothly continuous with the inner middle sipe via the inner shoulder main groove.

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