JP6545090B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire provided with a pair of cushion rubbers disposed between each end of the belt layer in the tire width direction and the carcass layer.

  Conventionally, as a pneumatic tire, a pneumatic tire provided with a pair of cushion rubbers disposed between each end of the belt layer in the tire width direction and the carcass layer is known (for example, Patent Document 1). By the way, in the tire, in particular, when the negative camber is set, the wear amount of the inner part at the time of wearing the vehicle tends to be larger than the wear amount of the outer part at the time of wearing the vehicle. Therefore, uneven wear occurs in the inner and outer portions when the vehicle is mounted.

JP, 2007-161142, A

  Therefore, in view of such a situation, an object of the present invention is to provide a pneumatic tire capable of suppressing the occurrence of uneven wear in an inner portion and an outer portion at the time of mounting on a vehicle.

  The pneumatic tire comprises a carcass layer disposed along the tire inner periphery, a belt layer disposed on the outer side in the tire radial direction of the carcass layer, each end of the belt layer in the tire width direction, and the carcass layer. And a pair of cushion rubbers disposed therebetween, wherein in the pair of cushion rubbers, the thickness dimension of the outer cushion rubbers disposed on the outer side when the vehicle is mounted is the inner cushion rubber disposed on the inner side when the vehicle is mounted Larger than the thickness dimension of.

  In the pneumatic tire, the thickness dimension of the outer cushion rubber may be 1.1 to 2.0 times the thickness dimension of the inner cushion rubber.

  In the pneumatic tire, the modulus of the outer cushion rubber may be larger than the modulus of the inner cushion rubber.

  The pneumatic tire may be configured such that the modulus of the outer cushion rubber is 1.2 to 2.0 times the modulus of the inner cushion rubber.

  As described above, the pneumatic tire has the excellent effect of being able to suppress the occurrence of uneven wear in the inner portion and the outer portion when the vehicle is mounted.

FIG. 1 is a cross-sectional view of an essential part of a tire meridional surface of a pneumatic tire according to an embodiment. FIG. 2 is an enlarged view of a region II of FIG. FIG. 3 is an enlarged view of a III region of FIG. FIG. 4 is an evaluation chart of the embodiment and the comparative example.

  Hereinafter, one embodiment of a pneumatic tire will be described with reference to FIGS. 1 to 4. In each of the drawings, the dimensional ratio of the drawings and the actual dimensional ratio do not necessarily coincide.

  As shown in FIG. 1, a pneumatic tire (hereinafter, also simply referred to as a “tire”) 1 according to the present embodiment includes a pair of bead portions 2 having beads 2 a and an outer side of each bead portion 2 in the tire radial direction D2. And a tread portion 4 which is connected to an end of the pair of sidewall portions 3 on the outer side in the tire radial direction D2 and which constitutes a tread surface. The tire 1 is a pneumatic tire into which air can be introduced, and is mounted on a rim (not shown).

  In FIG. 1, the tire width direction D1 is the left-right direction. The tire radial direction D2 is the diameter direction of the tire 1, and the tire circumferential direction is the direction around the tire rotation axis. In FIG. 1, in the tire radial direction D2, the tire radial direction D2 parallel to the paper surface is the vertical direction. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and located at the center of the tire width direction D1, and the tire meridional plane is a plane including the tire rotation axis and orthogonal to the tire equatorial plane S1. It is a face.

  The tire 1 is disposed on the inside of the carcass layer 5 and the carcass layer 5 which is bridged between the pair of beads 2a and 2a and wound up from the inside in the tire width direction D1 so as to wrap the beads 2a. The inner liner rubber 6 is excellent in the function of blocking the permeation of gas in order to maintain the air pressure. The carcass layer 5 and the inner liner rubber 6 are disposed along the tire inner circumference across the bead portion 2, the sidewall portion 3 and the tread portion 4.

  The carcass layer 5 is composed of two carcass plies 5a and 5b in the present embodiment. The carcass plies 5a and 5b include a plurality of ply cords arranged in a direction substantially orthogonal to the tire circumferential direction, and a topping rubber for covering the ply cords. For the ply cord, an organic fiber such as polyester, rayon, nylon, or aramid is used.

  The bead portion 2 includes a rim strip rubber 2 b disposed outside the tire width direction D1 of the carcass layer 5 so as to constitute the outer surface. The sidewall portion 3 is provided with sidewall rubbers 3a disposed outside the tire width direction D1 of the carcass layer 5 so as to constitute the outer surface.

  The tread portion 4 is provided with a tread rubber 7 disposed outside the tire radial direction D2 of the carcass layer 5 so as to constitute a tread surface (grounding surface) in contact with the ground. Further, the tread portion 4 is disposed between the carcass portion 5 and the belt portion 8 which is disposed on the outer side of the carcass layer 5 in the tire radial direction D2 and on the inner side of the tread rubber 7 in the tire radial direction D2. And a pair of cushion rubbers 9 and 10.

  The tread rubber 7 includes a plurality of circumferential grooves 7a extending along the tire circumferential direction. The belt portion 8 includes a belt layer 11 disposed outside the tire radial direction D2 of the carcass layer 5 in order to reinforce the carcass layer 5. Further, the belt portion 8 includes a belt reinforcing portion 12 disposed outside the tire radial direction D2 of the belt layer 11 and inside the tire radial direction D2 of the tread rubber 7 in order to reinforce the belt layer 11.

  The belt layer 11 includes at least two belt plies 11a and 11b. In the present embodiment, the belt layer 11 includes two layers of belt plies 11a and 11b. Each of the belt plies 11a and 11b includes a plurality of belt cords arranged in parallel, and a topping rubber that covers the belt cords.

  The belt plies 11a and 11b are stacked so that belt cords arranged at a predetermined inclination angle (for example, 15 ° to 35 °) with respect to the circumferential direction of the tire cross each other in opposite directions between the plies. There is. For the belt cord, organic fibers such as polyester, rayon, nylon, or aramid, and metals such as steel are preferably used.

  The belt reinforcing portion 12 is disposed to cover the belt layer 11 in the tire width direction D1. And belt reinforcement part 12 is provided with a reinforcement cord and topping rubber which covers a reinforcement cord. In the present embodiment, the belt reinforcing portion 12 includes two reinforcing plies 12 a and 12 b and has a two-layer structure.

  In the belt reinforcing portion 12, at least one reinforcing cord covered with topping rubber is wound in a spiral shape (inclination angle with respect to the tire circumferential direction is 0 to 5 °) along the tire circumferential direction. , Is formed. For the reinforcing cord, organic fibers such as polyester, rayon, nylon, or aramid are preferably used.

  The tire 1 according to the present embodiment has a structure that is asymmetric with respect to the tire equatorial plane S1. Such a tire 1 is a tire whose installation direction to a vehicle is designated, and when it is attached to a rim, it is designated which one of the left and right of the tire 1 faces the vehicle. The tread pattern formed on the tire outer surface of the tread portion 4 may be symmetrical or asymmetric with respect to the tire equatorial plane S1.

  The direction of attachment to the vehicle is displayed on the sidewall portion 3. Specifically, the sidewall rubber 3a has, on the surface thereof, a display unit for displaying the mounting direction of the vehicle. In the present embodiment, one sidewall portion 3 disposed on the inner side (left side in FIG. 1) when the vehicle is mounted is given an indication (for example, “INSIDE” or the like) indicating that it is to be the vehicle inner side. The other sidewall 3 disposed outside (right side in FIG. 1) when mounted on the vehicle is given an indication (e.g., "OUTSIDE" or the like) indicating that it will be outside the vehicle.

  In the tire width direction D1, a direction toward the inside when the vehicle is mounted is referred to as a vehicle inside direction D11, and a direction toward the outside when the vehicle is mounted is referred to as a vehicle outside direction D12. Of the pair of cushion rubbers 9 and 10, the cushion rubber 9 disposed inside when the vehicle is mounted is referred to as the inner cushion rubber 9, and the cushion rubber 10 disposed outside when the vehicle is mounted is the outer cushion rubber 10. .

  As shown in FIGS. 2 and 3, the cushion rubbers 9 and 10 are disposed between the end of the belt layer 11 in the tire width direction D <b> 1 and the carcass layer 5. Specifically, the cushion rubbers 9 and 10 are at least the end portions of the plurality of belt plies 11a and 11b that are arranged at the outermost side in the tire width direction D1 (in the present embodiment, the belt ply 11b And the carcass layer 5).

  Further, the cushion rubbers 9, 10 are disposed between the end of the belt ply 11b disposed at the innermost in the tire radial direction D2 and the carcass layer 5 among at least the plurality of belt plies 11a, 11b. There is. The rubber material (for example, modulus, rubber hardness, etc.) of the cushion rubbers 9 and 10 is different from the rubber material of the portion of the tread rubber 7 in contact with the cushion rubbers 9 and 10.

  The thickness dimension W2 of the outer cushion rubber 10 is larger than the thickness dimension W1 of the inner cushion rubber 9. As a result, since the ground contact length of the outer portion at the time of wearing the vehicle can be made longer, it is possible to suppress the occurrence of uneven wear at the inner portion and the outer portion at the time of wearing the vehicle. The thickness dimensions W1 and W2 of the cushion rubbers 9 and 10 are the belt in the direction of a perpendicular line (normal to the carcass layer 5 passing through the end of the belt layer 11) L1 from the end of the belt layer 11 to the carcass layer 5 The distance from the end of the layer 11 to the carcass layer 5 is referred to.

  The “end portion of the belt layer 11” is the end portion of the plurality of belt plies 11a and 11b that is disposed at the outermost in the tire width direction D1 (in the present embodiment, each of the belt plies 11b End). Moreover, such "carcass layer 5" is the carcass ply 5a in contact with the cushion rubbers 9 and 10 among the plurality of carcass plies 5a and 5b.

  The thickness dimension W2 of the outer cushion rubber 10 is not particularly limited with respect to the thickness dimension W1 of the inner cushion rubber 9, but is preferably 1.1 to 2.0 times the thickness dimension W1 of the inner cushion rubber 9. In the present embodiment, the thickness dimension W2 of the outer cushion rubber 10 is 1.3 times the thickness dimension W1 of the inner cushion rubber 9.

  For example, the thickness dimension W1 of the inner cushion rubber 9 is preferably 2.0 mm to 4.0 mm, and the thickness dimension W2 of the outer cushion rubber 10 is preferably 2.5 mm to 8.0 mm. In the present embodiment, the thickness dimension W1 of the inner cushion rubber 9 is 3 mm, and the thickness dimension W2 of the outer cushion rubber 10 is 4 mm.

  The thickness dimensions W1 and W2 of the cushion rubbers 9 and 10 are formed to be maximum at the end of the belt layer 11. And the cushion rubbers 9 and 10 are formed so that the cross-sectional shape cut by the tire meridional surface may be triangular.

  The area S2 of the outer side in the tire width direction D1 with respect to the perpendicular L1 from the end of the belt layer 11 to the carcass layer 5 in the cross section of the outer cushion rubber 10 cut at the tire meridional plane is the inner side in the tire width direction D1. The area S3 is preferably 100 to 150%, and more preferably 100 to 120%. In the present embodiment, the area S2 outside the tire width direction D1 is 100% of the area S3 inside the tire width direction D1.

  According to such a configuration, in the outer cushion rubber 10, the outer part (the part not in contact with the belt layer 11) in the tire width direction D1 is sandwiched between the inner part (the belt layer 11 and the carcass layer 5) in the tire width direction D1. Can be supported). Thereby, thickness dimension W2 of outer side cushion rubber 10 can be secured appropriately.

  The modulus of the outer cushion rubber 10 is larger than the modulus of the inner cushion rubber 9. Thereby, since the outer cushion rubber 10 has rigidity, for example, steering stability performance at the time of turning can be improved, and the inner cushion rubber 9 is formed to be relatively soft, for example, cushioning effect As it has, durability performance can be improved. In the present embodiment, such “modulus” is 100% tensile modulus measured at 23 ° C. in accordance with JIS K6251.

  The modulus of the outer cushion rubber 10 is not particularly limited with respect to the modulus of the inner cushion rubber 9, but is preferably 1.2 to 2.0 times the modulus of the inner cushion rubber 9. In the present embodiment, the modulus of the outer cushion rubber 10 is 1.5 times the modulus of the inner cushion rubber 9.

  For example, the modulus of the inner cushion rubber 9 is preferably 1.5 MPa to 4.0 MPa, and the modulus of the outer cushion rubber 10 is preferably 2.0 MPa to 6.0 MPa. In the present embodiment, the modulus of the inner cushion rubber 9 is 2.4 MPa, and the modulus of the outer cushion rubber 10 is 3.6 MPa.

  Further, in the present embodiment, the modulus of the outer cushion rubber 10 is larger than the modulus of the portion of the tread rubber 7 in contact with the outer cushion rubber 10. Thereby, for example, steering stability performance at the time of turning can be effectively improved. The modulus of the outer cushion rubber 10 may be smaller than the modulus of the portion of the tread rubber 7 in contact with the outer cushion rubber 10.

  Further, in the present embodiment, the modulus of the inner cushion rubber 9 is smaller than the modulus of the portion of the tread rubber 7 in contact with the inner cushion rubber 9. Thereby, for example, the durability can be effectively improved. The modulus of the inner cushion rubber 9 may be larger than the modulus of the portion of the tread rubber 7 in contact with the inner cushion rubber 9.

  From the above, the pneumatic tire 1 according to the present embodiment includes the carcass layer 5 disposed along the inner periphery of the tire, the belt layer 11 disposed outside the tire radial direction D2 of the carcass layer 5, and the belt A pair of cushion rubbers 9, 10 disposed between each end of the layer 11 in the tire width direction D1 and the carcass layer 5, and the pair of cushion rubbers 9, 10 is provided on the outside when the vehicle is mounted The thickness dimension W2 of the outer cushion rubber 10 disposed is larger than the thickness dimension W1 of the inner cushion rubber 9 disposed inside when the vehicle is mounted.

  According to such a configuration, the pair of cushion rubbers 9 and 10 is disposed between each end of the belt layer 11 in the tire width direction D1 and the carcass layer 5. And in a pair of cushion rubbers 9 and 10, thickness dimension W2 of outside cushion rubber 10 arranged outside at the time of vehicles wearing becomes larger than thickness dimension W 1 of inner cushion rubbers 9 arranged inside at the time of vehicles wearing There is. As a result, since the ground contact length of the outer portion at the time of wearing the vehicle can be made longer, it is possible to suppress the occurrence of uneven wear at the inner portion and the outer portion at the time of wearing the vehicle.

  In the pneumatic tire 1 according to the present embodiment, the thickness dimension W2 of the outer cushion rubber 10 is 1.1 times to 2.0 times the thickness dimension W1 of the inner cushion rubber 9. .

  According to such a configuration, since the thickness dimension W2 of the outer cushion rubber 10 is 1.1 to 2.0 times the thickness dimension W1 of the inner cushion rubber 9, the contact length of the outer portion when the vehicle is mounted; The grounding length of the inner portion when mounted on the vehicle is more even. This makes it possible to effectively suppress the occurrence of uneven wear on the inner and outer portions when the vehicle is mounted.

  In the pneumatic tire 1 according to the present embodiment, the modulus of the outer cushion rubber 10 is larger than the modulus of the inner cushion rubber 9.

  According to such a configuration, the modulus of the outer cushion rubber 10 is larger than the modulus of the inner cushion rubber 9. Thus, the modulus of the outer cushion rubber 10 having a large thickness dimension W2 is set large, so the outer cushion rubber 10 has rigidity. Therefore, for example, steering stability performance at the time of turning can be improved.

  Moreover, since the modulus of the inner cushion rubber 9 having a small thickness dimension W1 is set small, the inner cushion rubber 9 is formed to be relatively soft. Therefore, since the inner cushion rubber 9 has, for example, a buffer effect, durability performance can be improved.

  Moreover, the pneumatic tire 1 according to the present embodiment is configured such that the modulus of the outer cushion rubber 10 is 1.2 times to 2.0 times the modulus of the inner cushion rubber 9.

  According to such a configuration, since the modulus of the outer cushion rubber 10 is 1.2 to 2.0 times the modulus of the inner cushion rubber 9, the rigidity of the outer cushion rubber 10 and the softness of the inner cushion rubber 9 It is possible to make it appropriate. Thereby, for example, both steering stability performance at the time of turning and durability performance can be effectively improved.

  In addition, a pneumatic tire is not limited to the structure of above-described embodiment, Moreover, it is not limited to the above-mentioned effect. Of course, the pneumatic tire can be variously modified without departing from the scope of the present invention. For example, as a matter of course, one or a plurality of configurations, methods, and the like according to various modifications described below may be arbitrarily selected and adopted as the configuration, the method, and the like according to the above-described embodiment.

  In the pneumatic tire 1 according to the above embodiment, the modulus of the outer cushion rubber 10 is larger than the modulus of the inner cushion rubber 9. However, the pneumatic tire is not limited to such a configuration.

  For example, in a pneumatic tire, the modulus of the outer cushion rubber 10 may be the same as the modulus of the inner cushion rubber 9 or larger than the modulus of the inner cushion rubber 9. For example, in order to improve steering stability performance and durability performance at the time of turning, a configuration in which the modulus of the outer cushion rubber 10 is larger than the modulus of the inner cushion rubber 9 is preferable.

  Further, the pneumatic tire 1 is not limited to the case where the negative camber is set when mounted on a vehicle. For example, when the pneumatic tire 1 is mounted on a vehicle, a positive camber may be set, or may be a zero camber with a camber angle of zero.

  Here, in order to specifically show the configuration and effects of the pneumatic tire 1, an embodiment of the pneumatic tire 1 and a comparative example thereof will be described below with reference to FIG. 4.

<Uneven wear resistance>
After each tire was mounted on a vehicle and traveled 10,000 km on a general road, the average wear amount of the circumferential groove 7a inside the vehicle and the average wear amount of the circumferential groove 7a outside the vehicle were measured. The average wear amount of the circumferential groove 7a on the inner side of the vehicle divided by the average wear amount of the circumferential groove 7a on the outer side of the vehicle is evaluated by an index based on the result of the comparative example being 100. Show that it is excellent.

<Durable performance>
The drum test was conducted in accordance with the conditions defined by ECE-R30, and no failure was found under the specified speed and time conditions, and each tire passed each test, so every 10 minutes, the speed was 10 km. The speed was increased by / h and the drum travel was continued until failure, and the travel distance to the time of failure occurrence was measured. It evaluates by the index which sets the result of a comparative example to 100, and it shows that endurance performance is excellent, so that an index is large.

Steering stability performance
Each tire was attached to a vehicle, and a turning on a dry road surface was performed. And the steering stability performance was evaluated by the evaluation content that the behavior at the time of turning was a linear response by the sensory test of a driver, and it was excellent, so that there was little rocking of a vehicle. The result of the comparative example is evaluated by an index of 100, and the larger the index is, the better the steering stability is.

Examples 1 to 8
Example 1 relates to the tire according to the above embodiment (the thickness dimension W2 of the outer cushion rubber 10 is 1.3 times the thickness dimension W1 of the inner cushion rubber 9, and the modulus of the outer cushion rubber 10 is the modulus of the inner cushion rubber 9 Is 1.5 times of
The second embodiment is a tire in which the thickness dimension W2 of the outer cushion rubber 10 is 1.1 times the thickness dimension W1 of the inner cushion rubber 9 with respect to the tire according to the first embodiment.
The third embodiment is a tire in which the thickness dimension W2 of the outer cushion rubber 10 is 2.0 times the thickness dimension W1 of the inner cushion rubber 9 in the tire according to the first embodiment.
The fourth embodiment is a tire in which the thickness dimension W2 of the outer cushion rubber 10 is 2.5 times the thickness dimension W1 of the inner cushion rubber 9 with respect to the tire according to the first embodiment.
The fifth embodiment is a tire in which the modulus of the outer cushion rubber 10 is 1.2 times the modulus of the inner cushion rubber 9 in the tire according to the first embodiment.
Example 6 is a tire in which the modulus of the outer cushion rubber 10 is 2.0 times the modulus of the inner cushion rubber 9 with respect to the tire according to the example 1.
The seventh embodiment is a tire in which the modulus of the outer cushion rubber 10 is 1.0 times the modulus of the inner cushion rubber 9 with respect to the tire according to the first embodiment.
The eighth embodiment is a tire in which the modulus of the outer cushion rubber 10 is 3.0 times the modulus of the inner cushion rubber 9 in the tire according to the first embodiment.

Comparative Example
In the comparative example, the thickness dimension W2 of the outer cushion rubber 10 is the same as the thickness dimension W1 of the inner cushion rubber 9 and the modulus of the outer cushion rubber 10 is the inner cushion rubber 9 in the tire according to the first embodiment. It is a tire that has been changed to a configuration that is the same as the modulus.

<Evaluation result>
Examples 1 to 8 can improve the uneven wear resistance performance as compared to the comparative example. Thus, in Examples 1 to 8, since the thickness dimension W2 of the outer cushion rubber 10 is larger than the thickness dimension W1 of the inner cushion rubber 9, the uneven wear resistance can be improved.

  Further, more preferable embodiments of the tire will be described below.

  First, in the tires according to Examples 1 to 3 and 5 to 8, the thickness dimension W2 of the outer cushion rubber 10 is 1.1 to 2.0 times the thickness dimension W1 of the inner cushion rubber 9. is there. On the other hand, in the tire according to the fourth embodiment, the thickness dimension W2 of the outer cushion rubber 10 is 2.5 times the thickness dimension W1 of the inner cushion rubber 9.

  And although the tire according to Example 4 can improve the uneven wear resistance, in the tires according to Examples 1 to 3 and 5 to 8, the uneven wear resistance is very high. It has been able to improve effectively. Thus, in the tire, the thickness dimension W2 of the outer cushion rubber 10 is preferably 1.1 to 2.0 times the thickness dimension W1 of the inner cushion rubber 9.

  In the tire according to Examples 1 to 6, the modulus of the outer cushion rubber 10 is 1.2 to 2.0 times the modulus of the inner cushion rubber 9. On the other hand, in the tire according to Example 7, the modulus of the outer cushion rubber 10 is 1.0 times the modulus of the inner cushion rubber 9, and in the tire according to Example 8, the outer side is The modulus of the cushion rubber 10 is 3.0 times the modulus of the inner cushion rubber 9.

  And in the tire concerning Example 7, while being able to maintain endurance performance, steering stability is lowered a little, and, in the tire concerning Example 8, endurance performance and steering stability performance are carried out. In the tires according to Examples 1 to 6, the durability performance and the steering stability performance can be improved. Thus, in the tire, the modulus of the outer cushion rubber 10 is preferably 1.2 to 2.0 times the modulus of the inner cushion rubber 9.

DESCRIPTION OF SYMBOLS 1 ... pneumatic tire, 2 ... bead part, 2a ... bead, 2b ... rim strip rubber, 3 ... sidewall part, 3a ... sidewall rubber, 4 ... tread part, 5 ... carcass layer, 5a ... carcass ply, 5b ... Carcass ply, 6: inner liner rubber, 7: tread rubber, 7a: circumferential groove, 8: belt portion, 9: inner cushion rubber, 10: outer cushion rubber, 11: belt layer, 11a: belt ply, 11b: belt ply , 12: belt reinforcing portion, 12a: reinforcing ply, 12b: reinforcing ply, D1: tire width direction, D2: tire radial direction, D11: vehicle inner direction, D12: vehicle outer direction, S1: tire equatorial plane, W1: thickness Dimension, W2 ... thickness dimension

Claims (4)

A carcass layer disposed along the inner periphery of the tire,
A belt layer disposed on the outer side in the tire radial direction of the carcass layer;
A pair of cushion rubbers disposed between each end of the belt layer in the tire width direction and the carcass layer;
In the pair of cushion rubbers, a pneumatic tire in which a thickness dimension of an outer cushion rubber disposed outside at the time of mounting on a vehicle is larger than a thickness dimension of an inner cushion rubber disposed at the inside at the time of mounting on a vehicle.   The pneumatic tire according to claim 1, wherein a thickness dimension of the outer cushion rubber is 1.1 times to 2.0 times a thickness dimension of the inner cushion rubber.   The pneumatic tire according to claim 1, wherein a modulus of the outer cushion rubber is larger than a modulus of the inner cushion rubber. The pneumatic tire according to claim 3, wherein the modulus of the outer cushion rubber is 1.2 to 2.0 times the modulus of the inner cushion rubber.

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