阅读说明：本技术 轮胎 (Tyre for vehicle wheels ) 是由 本田真悟 于 2020-05-07 设计创作，主要内容包括：充气轮胎(10)的胎体(40)的主体部(41)和折回部(42)的局部由多张帘布层(41a)、帘布层(41b)、帘布层(42a)、帘布层(42b)构成。充气轮胎(10)包括：胎圈包布(70),其以覆盖胎圈芯(61)和胎圈填胶(62)的方式从轮胎宽度方向内侧经由胎圈芯(61)向轮胎宽度方向外侧折回；以及嵌入件(80),其设于胎圈填胶(62)与向轮胎宽度方向外侧折回的胎圈包布(70)之间。在设有嵌入件(80)的至少一部分区域中,胎侧橡胶(31)的厚度(D1)、厚度(D2)与将主体部(41)和折回部(42)合并而得到的帘布层厚度大致相同。(A main body part (41) and a folded part (42) of a carcass (40) of a pneumatic tire (10) are partially composed of a plurality of plies (41a), plies (41b), plies (42a), and plies (42 b). A pneumatic tire (10) comprises: a chafer (70) folded back from the inner side in the tire width direction to the outer side in the tire width direction via the bead core (61) so as to cover the bead core (61) and the bead filler (62); and an insert (80) provided between the bead filler (62) and the chafer (70) folded back outward in the tire width direction. In at least a part of the region where the insert (80) is provided, the thickness (D1) and the thickness (D2) of the side wall rubber (31) are substantially the same as the thickness of a ply layer obtained by combining the main body portion (41) and the folded-back portion (42).)

1. A tire, comprising:

a tread portion that contacts a road surface;

a sidewall portion that is connected to the tread portion and is located on a tire radial direction inner side of the tread portion;

a bead portion that is connected to the sidewall portion, located on a tire radial direction inner side of the sidewall portion; and

a carcass, which forms a tire frame,

wherein the content of the first and second substances,

the bead portion includes a bead core and a bead filler provided on a tire radial direction outer side of the bead core,

the carcass has:

a main body portion; and

a folded-back portion that is continuous with the main body portion and is folded back toward the outer side in the tire width direction via a bead core,

the main body and the folded-back portion are partially composed of at least a plurality of plies,

the tire includes:

a first reinforcing member 1 folded back from the inner side in the tire width direction to the outer side in the tire width direction via the bead core so as to cover the bead core and the bead filler; and

a 2 nd reinforcing member provided between the bead filler and the 1 st reinforcing member folded back outward in the tire width direction,

in at least a part of the region where the 2 nd reinforcing member is provided, a thickness of a sidewall rubber provided on an outer side of the carcass in the tire width direction is substantially the same as a ply thickness obtained by combining the main body portion and the folded-back portion composed of a plurality of plies.

2. The tire according to claim 1, wherein,

the thickness of the sidewall rubber at a maximum width position of the tire is 40% or more of a cross-sectional width at the maximum width position of the sidewall portion.

3. The tire according to claim 1 or 2,

the thickness of the sidewall rubber at the position of a rim line of the tire is 30% or more of the cross-sectional width of the bead portion at the position of the rim line.

4. A tire according to any one of claims 1 to 3,

the thickness of the sidewall rubber at the maximum width position of the tire is substantially the same as the thickness of 4 plies.

5. Tire according to any one of claims 1 to 4,

the 1 st reinforcing member includes:

an inner portion located on a tire width direction inner side of the bead portion; and

an outer portion located on the tire width direction outer side of the bead portion,

the outer end of the outer portion in the tire radial direction is located further toward the outer side in the tire radial direction than the outer end of the inner portion in the tire radial direction, and is located further toward the outer side in the tire radial direction than a position of 50% of the cross-sectional height of the tire.

6. The tire according to claim 5,

the outer end of the 2 nd reinforcing member in the tire radial direction is located further inward in the tire radial direction than a position of 50% of the cross-sectional height.

Technical Field

The present invention relates to a tire having high turning performance.

Background

Conventionally, in a pneumatic tire (hereinafter, referred to as a tire) mounted on a four-wheel vehicle, a structure is known in which a side reinforcing layer made of rubberized fabric of a plurality of cords is provided in a side portion of the tire for the purpose of improving steering performance (see patent document 1).

Such a side reinforcing layer is provided so as to extend from the tire width direction outer end of the belt layer provided on the inner side of the tread portion in the tire radial direction to the tire radial direction outer end of the bead portion. Thereby, the rigidity of the side portion is improved, and therefore the grip force and the responsiveness in steering of the vehicle can be improved.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-274799

Disclosure of Invention

However, as the performance of the vehicle is improved, further improvement in steering performance, in particular, improvement in drivability in a limit region of tire performance (grip force and the like) during steering (hereinafter, referred to as limit region drivability) is required.

In general, by improving the axial force in a small steering angle region at the start of steering, the shear deformation of the tread portion in a large steering angle region after the approach angle is optimized, and improvement in performance such as grip force and responsiveness can be expected.

In addition, in order to improve the operability in the limited region, it is essential to effectively function the ground contact surface of the tread portion. In particular, in order to increase the axial force, it is essential to promote shear deformation of the tread portion. As a method of promoting such shear deformation of the tread portion, there is a method of improving the main body rigidity of the tire.

However, if the body stiffness of the tire is increased, the damping property of the tire during steering (the ease of flexing of the tire in the tire radial direction) is reduced, and it is therefore difficult to maintain the posture of the vehicle in a state in which a load is applied to the tire during steering. Therefore, the time dependence of the lateral force (Fy) is reduced.

The present invention has been made in view of such circumstances, and an object thereof is to provide a tire that can achieve both improvement of an axial force during steering and ease of maintaining a vehicle posture at a high level.

A tire (pneumatic tire 10) according to an aspect of the present invention includes: a tread portion (tread portion 20) which comes into contact with a road surface; a sidewall portion (sidewall portion 30) that is continuous with the tread portion and is located on the inner side of the tread portion in the tire radial direction; a bead portion (bead portion 60) that is connected to the side portion, and is located on the tire radial direction inner side of the side portion; and a carcass (carcass 40) forming a tire frame, wherein the bead portion includes a bead core (bead core 61) and a bead filler (bead filler 62) provided outside the bead core in a tire radial direction, the carcass has a main portion (main portion 41) and a folded-back portion (folded-back portion 42) connected to the main portion and folded-back to an outside in a tire width direction via the bead core, and portions of the main portion and the folded-back portion are constituted by at least a plurality of plies (ply 41a, ply 41b, ply 42a, ply 42b), and the tire includes: a 1 st reinforcing member (chafer 70) folded back from the inner side in the tire width direction to the outer side in the tire width direction via the bead core so as to cover the bead core and the bead filler; and a 2 nd reinforcing member (insert 80) provided between the bead filler and the 1 st reinforcing member folded back to the outside in the tire width direction, wherein in at least a part of a region where the 2 nd reinforcing member is provided, thicknesses (thickness D1, thickness D2) of a side rubber (side rubber 31) provided to the outside in the tire width direction of the carcass are substantially the same as a ply thickness obtained by combining the main body portion and the folded-back portion composed of a plurality of plies.

Drawings

Fig. 1 is a sectional view of a pneumatic tire 10.

Fig. 2 is a partial sectional view of the pneumatic tire 10.

Fig. 3 is a partially enlarged sectional view of the pneumatic tire 10.

Detailed Description

Hereinafter, embodiments will be described based on the drawings. The same or similar reference numerals are used for the same functions and structures, and the description thereof is appropriately omitted.

(1) General structure of tire as a whole

Fig. 1 is a sectional view of a pneumatic tire 10 of the present embodiment. Specifically, fig. 1 is a cross-sectional view of the pneumatic tire 10 along the tire width direction and the tire radial direction. In fig. 1, the hatching of the cross section is not shown.

As shown in fig. 1, the pneumatic tire 10 includes a tread portion 20, a sidewall portion 30, a carcass 40, a belt 50, and a bead portion 60.

In the present embodiment, the pneumatic tire 10 is a tire that is mounted on a four-wheeled vehicle, specifically, a passenger vehicle. In particular, the pneumatic tire 10 can be suitably used for a four-wheeled vehicle such as a sport type vehicle in which steering performance is regarded as important.

The tread portion 20 is a portion that contacts the road surface. The tread portion 20 is formed with a pattern (not shown) corresponding to the usage environment of the pneumatic tire 10 and the type of vehicle to which the tire is mounted.

The sidewall portion 30 is connected to the tread portion 20, and is located on the tire radial direction inner side of the tread portion 20. The side portion 30 is a region from the tire width direction outer end of the tread portion 20 to the upper end of the bead portion 60. The sidewall portion 30 is also sometimes called a sidewall (sidewall) or the like.

The carcass 40 forms a skeleton (tire skeleton) of the pneumatic tire 10. In the present embodiment, the carcass 40 has a radial structure in which carcass cords (not shown) radially arranged in the tire radial direction are covered with a rubber material. The carcass 40 has a main body portion 41 and a folded-back portion 42.

The main body portion 41 is a portion provided astride the tread portion 20, the sidewall portion 30, and the bead portion 60 and folded back at the bead portion 60.

The folded portion 42 is a portion that is continuous with the main body portion 41 and is folded back toward the outer side in the tire width direction via the bead core 61. The outer end 42e of the folded-back portion 42 in the tire radial direction extends to the tire radial direction inner side of the belt layer 50. That is, an envelope configuration is adopted in the carcass 40.

However, the carcass 40 does not need to have an envelope structure, and may have a high turn-up structure in which the outer end 42e is located on the tire radial direction inner side of the belt layer 50 without reaching the belt layer 50, specifically, in the vicinity of the maximum width position Wmax (not shown in fig. 1, see fig. 2), for example.

The carcass cord is formed using an organic fiber such as nylon as in a tire for a general four-wheeled vehicle. In the present embodiment, the carcass 40 is configured using a plurality of plies (carcass plies). The structure of the carcass 40 will be described later.

The belt layer 50 is provided on the tire radial direction inner side of the tread portion 20. In the present embodiment, the belt layer 50 includes a pair of cross belts in which steel cords cross. Further, the belt layer 50 may include a reinforcing belt provided at an end portion in the tire width direction of the intersecting belt.

The bead portion 60 is connected to the sidewall portion 30 and located on the inner side of the sidewall portion 30 in the tire radial direction. The bead portion 60 is annular and extends in the tire circumferential direction, and is locked to a rim (not shown).

The bead portion 60 includes a bead core 61 and a bead filler 62.

The bead core 61 is formed by twisting a plurality of metal cords. For example, the bead core 61 can be formed of steel cords. The number of cords (number of cores) is not particularly limited, and is about 24 cores in the present embodiment.

The bead filler 62 is provided on the tire radial direction outer side of the bead core 61. The bead filler 62 is formed using a rubber harder than the other portions formed using the rubber. The bead filler 62 is provided so as to fill a space having a wedge-shaped cross-sectional shape formed by the main body portion 41 and the folded-back portion 42 of the carcass 40.

In addition, in the present embodiment, a second bead filler 65 is provided. The second bead filler 65 is provided on the tire width direction outer side of the folded-back portion 42 of the carcass 40. The second bead filler 65 is also formed of the same member as the bead filler 62.

In addition, the pneumatic tire 10 includes a chafer 70 and an insert 80.

The chafer 70 is provided so as to cover the periphery of the bead portion 60. Specifically, the chafer 70 is folded back from the tire width direction inner side to the tire width direction outer side via the bead core 61 so as to cover the bead core 61 and the bead filler 62.

The chafer 70 has a structure in which a plurality of cords arranged obliquely with respect to the tire radial direction are covered with rubber. As the cord, an organic fiber such as aramid fiber can be used.

The chafer 70 reinforces the bead portion 60. In the present embodiment, the chafer 70 constitutes the 1 st reinforcing member.

The insert 80 is provided on the tire width direction outer side of the bead filler 62. Specifically, the insert 80 is provided between the bead filler 62 and the chafer 70 folded back outward in the tire width direction.

The insert 80 is also configured by covering a plurality of cords arranged obliquely with respect to the tire radial direction with rubber. As the cord, organic fibers such as aramid fibers or metals such as steel can be used.

The inserts 80 reinforce the sidewall portions 30 and the bead portions 60. In the present embodiment, the insert 80 constitutes the 2 nd reinforcing member.

The chafer 70 and the insert 80 may also be referred to as a sidewall reinforcement layer or the like.

A rim line 90 is provided on the tire width direction outer side surface of the bead portion 60. The rim line 90 is a convex portion formed along the tire circumferential direction to confirm whether or not the bead portion 60 is properly mounted on the rim. In the present embodiment, the rim line 90 is provided at a position that is about 6mm outside the tire radial direction outer end of the rim flange 110 in the tire radial direction.

(2) Structure of the sidewall 30 and the bead portion 60

Fig. 2 is a partial sectional view of the pneumatic tire 10. In fig. 2, only a part of the members is shown in cross-sectional hatching for easy recognition.

As shown in fig. 2, in the present embodiment, the carcass 40 is composed of a plurality of plies (carcass plies). Specifically, the main body 41 is composed of two carcass plies.

The folded-back portion 42 is partially composed of two plies.

More specifically, the main body portion 41 is constituted by a ply layer 41a and a ply layer 41 b. The turnback portion 42 is composed of a ply 42a and a ply 42 b. The ply 42b terminates near the center of the bead filler 62 in the tire radial direction.

The chafer 70 has an inner portion 71 and an outer portion 72. The inner portion 71 is a portion located on the tire width direction inner side of the bead portion 60. The outer side portion 72 is a portion located on the tire width direction outer side of the bead portion 60.

In addition, the sidewall portion 30 has a tire width of the pneumatic tire 10, that is, a maximum width position Wmax at which a width along the tire width direction becomes maximum. In the present embodiment, the maximum width position Wmax is a position at which the width in the tire width direction becomes maximum in the pneumatic tire 10 with no rim assembled.

(3) Detailed structure of the sidewall 30 and the bead 60

Fig. 3 is a partially enlarged sectional view of the pneumatic tire 10. In fig. 3, as in fig. 2, only a part of the members is shown in cross-sectional hatching for easy recognition.

As described above, the main body portion 41 and the folded-back portion 42 of the carcass 40 are formed of a plurality of, specifically, two plies, and the thickness of the side rubber 31 provided on the outer side in the tire width direction of the carcass 40 in at least a part of the region where the insert 80 is provided is substantially the same as the thickness of a ply obtained by combining the main body portion 41 and the folded-back portion 42 formed of a plurality of plies.

Specifically, the thickness D1 of the side rubber 31 is substantially the same as the ply thickness obtained by combining the ply 41a, the ply 41b, the ply 42a, and the ply 42 b. In the present embodiment, the ply thicknesses of the ply layer 41a, the ply layer 41b, the ply layer 42a, and the ply layer 42b are about 1mm, respectively. Thus, the thickness D1 is about 4 mm. By "substantially the same" is meant that the thickness D1 is within ± 10% of the combined thickness of the plurality of plies.

The thickness D1 is the thickness at the maximum width position Wmax of the side wall rubber 31. The thickness D1, i.e., the thickness at the maximum width position Wmax of the side rubber 31 is 40% or more of the cross-sectional width (D1 + D1' in the drawing) at the maximum width position Wmax of the side portion 30. The cross-sectional width is a thickness of the entire sidewall portion 30 along a straight line orthogonal to the tire width direction outer side surface of the sidewall portion 30 in the tire cross-sectional view as shown in fig. 3.

That is, in the present embodiment, the thickness of the sidewall rubber 31 at the maximum width position Wmax is substantially the same as the thickness of the 4 plies (the ply 41a, the ply 41b, the ply 42a, and the ply 42b) constituting the carcass 40.

The thickness D2 at the position of the rim line 90 of the side rubber 31 is also substantially the same as the ply thickness obtained by combining the plies 41a, 41b, 42a, and 42 b. The thickness D2 is 30% or more of the cross-sectional width (D2 + D2' in the figure) of the bead portion 60 at the position of the rim line 90.

The cross-sectional width is a thickness of the entire bead portion 60 along a straight line orthogonal to the tire width direction outer side surface of the bead portion 60 in the tire cross-sectional view as shown in fig. 3. As shown in fig. 3, a plurality of rim lines 90 may be provided, and in such a case, the rim line 90 provided on the outermost side in the tire radial direction is used as a reference. The thickness D2 does not include the portion of the rim line 90 that protrudes from the tire width direction outer side surface of the bead portion 60.

In the present embodiment, the thickness D1 and the thickness D2 do not include the thickness of the second bead filler 65. That is, the thickness D1 (thickness D2) is the distance from the tire width direction outer side surface of the second bead filler 65 to the tire width direction outer side surface of the folded back portion 42 (ply 42a) of the carcass 40.

In addition, the chafer 70 (outer side portion 72) and the insert 80 are provided at the positions of the thickness D1 and the thickness D2 in the tire radial direction.

Further, the outer end 72a of the outer portion 72 of the chafer 70 in the tire radial direction is located further toward the outside in the tire radial direction than the outer end 71a of the inner portion 71 of the chafer 70 in the tire radial direction. The outer end 72a is located on the outer side in the tire radial direction than the position 50% of the cross-sectional height SH of the pneumatic tire 10.

The cross-sectional height SH refers to a height from the tire radial direction inner end of the bead portion 60 of the pneumatic tire 10 with an unassembled rim to the tire radial direction outer end of the tread portion 20. In the present embodiment, the outer end 72a is provided at a position 54% of the sectional height SH. The position of 54% of the cross-sectional height SH is based on the tire radial direction inner end of the bead portion 60 (the same applies hereinafter).

Further, the outer end 71a of the inner portion 71 of the chafer 70 in the tire radial direction is provided at a position of 20% of the sectional height SH.

The outer end 80a of the insert 80 in the tire radial direction is located inward in the tire radial direction from the position of 50% of the section height SH. In the present embodiment, the outer end 80a is provided at a position 46% of the sectional height SH.

The outer end 65a of the second bead filler 65 in the tire radial direction is located closer to the maximum width position Wmax and further inward in the tire radial direction than the maximum width position Wmax.

(4) Action and Effect

According to the above embodiment, the following operational effects are obtained. Specifically, the bead portion 60 of the pneumatic tire 10 is provided with the chafer 70 (the 1 st reinforcing member), and the insert 80 (the 2 nd reinforcing member) is provided between the bead filler 62 and the outer portion 72 of the chafer 70.

In at least a part of the region where the insert 80 is provided, the thickness D1 of the side rubber 31 is substantially the same as the thickness of a ply obtained by combining the main body portion 41 and the folded-back portion 42 of the carcass 40 composed of a plurality of plies.

The thickness of the side rubber 31 is thicker than that of a conventional pneumatic tire of the same kind. Specifically, the thickness of the rubber (thickness D1 and thickness D2) becomes thicker as it goes from the maximum width position Wmax to the rim line 90. That is, the thickness of the sidewall rubber 31 is thickened at least partially at the portion where the chafer 70 and the insert 80 are provided in the tire radial direction.

By increasing the thickness of the side rubber 31 (thick gauge) and disposing the chafer 70 and the insert 80, the longitudinal rigidity and the damping property of the pneumatic tire 10 can be improved without increasing the body rigidity.

More specifically, the longitudinal rigidity is increased due to the thickness gauge of the side rubber 31, thereby promoting shear deformation of the tread portion 20, which is relatively easily deformed compared to the side portion 30. In addition, the shape of the carcass 40 (the cross-sectional shape along the tire width direction and the tire radial direction) is difficult to deform, so that an improvement in the axial force of the pneumatic tire 10 in steering can be achieved.

Further, since the thickness of the side rubber 31 is normalized and the damping property of the tire during steering (the ease of flexing of the tire (carcass 40) in the tire radial direction) can be optimized, the posture of the vehicle during steering can be easily maintained.

That is, according to the pneumatic tire 10, it is possible to achieve both improvement of the axial force during steering and easiness of maintaining the posture of the vehicle at a high level. Further, the ease of maintaining the vehicle posture while maintaining the axial force during steering and the vehicle posture at a high level can contribute to improvement of the controllability in the limit region of the tire performance (such as the grip force) during steering.

Further, the body rigidity refers to the rigidity (stiffness) of the carcass 40 itself forming the tire frame (body).

In the present embodiment, the thickness of the sidewall rubber 31 at the maximum width position Wmax is 40% or more of the cross-sectional width of the sidewall portion 30 at the maximum width position Wmax. The thickness D2 at the position of the rim line 90 of the side rubber 31 is 30% or more of the cross-sectional width at the position of the rim line 90 of the bead portion 60. Therefore, the relative thickness of the sidewall rubber 31 spanning from the sidewall portion 30 to the bead portion 60 becomes thick. This can more appropriately improve the longitudinal stiffness and the damping property of the pneumatic tire 10, and can further achieve both improvement of the axial force during steering and ease of maintaining the vehicle posture at a high level.

In the present embodiment, the thickness of the sidewall rubber 31 at the maximum width position Wmax is substantially the same as the thickness of the 4 plies (the ply 41a, the ply 41b, the ply 42a, and the ply 42b) constituting the carcass 40. Therefore, balance with the body rigidity of the carcass 40 can be ensured, and the longitudinal rigidity and the damping property of the pneumatic tire 10 can be more appropriately improved. This makes it possible to achieve both an improvement in the axial force during steering and an ease of maintaining the vehicle posture at a higher level.

In the present embodiment, the outer end 72a of the outer portion 72 of the chafer 70 in the tire radial direction is located further toward the outside in the tire radial direction than the outer end 71a of the inner portion 71 of the chafer 70 in the tire radial direction.

The outer end 80a of the insert 80 in the tire radial direction is located inward in the tire radial direction from the position of 50% of the cross-sectional height SH. The outer end 65a of the second bead filler 65 in the tire radial direction is located closer to the maximum width position Wmax and further inward in the tire radial direction than the maximum width position Wmax.

Therefore, it is possible to impart characteristics contributing to appropriate improvements in the longitudinal rigidity and the attenuation of the pneumatic tire 10 to the side portion 30 over a wide range in the tire radial direction of the side portion 30. This can achieve a further high level of compatibility between the improvement of the axial force during steering and the ease of maintaining the vehicle posture.

(5) Other embodiments

While the present invention has been described with reference to the embodiments, it is obvious to those skilled in the art that the present invention is not limited to the above description, and various modifications and improvements can be made.

For example, although the second bead filler 65 is provided in the above embodiment, the second bead filler 65 may not be necessarily provided. In this case, the thickness D1 (thickness D2) of the sidewall rubber 31 is a distance from the tire width direction outer side surface of the sidewall portion 30 (bead portion 60) to the tire width direction outer side surface of the folded-back portion 42 (ply 42a) of the carcass 40.

In the above-described embodiment, the outer end 80a of the insert 80 in the tire radial direction is located inward in the tire radial direction from the position of 50% of the sectional height SH, and the outer end 65a of the second bead filler 65 in the tire radial direction is located closer to the maximum width position Wmax and inward in the tire radial direction from the maximum width position Wmax, but such a positional relationship is not necessarily required.

In the above-described embodiment, the outer end 72a of the outer portion 72 of the chafer 70 in the tire radial direction is located further toward the outside in the tire radial direction than the outer end 71a of the inner portion 71 of the chafer 70 in the tire radial direction, but such a positional relationship is not essential.

As described above, although the embodiments of the present invention have been described, the present invention should not be limited to the description and drawings constituting a part of the present disclosure. Various alternative embodiments, examples, and application techniques will be apparent to those skilled in the art in light of this disclosure.

Description of the reference numerals

10. A pneumatic tire; 20. a tread portion; 30. a sidewall portion; 31. a sidewall rubber; 40. a carcass; 41. a main body portion; 41a, a ply layer; 41b, a ply layer; 42. a fold-back portion; 42a, a ply layer; 42b, a ply layer; 42e, an outer end; 50. a belt ply; 60. a bead portion; 61. a bead core; 62. a bead filler; 65. a second bead filler; 65a, an outer end; 70. a chafer; 71. an inner portion; 71a, an outer end; 72. an outer portion; 72a, an outer end; 80. an insert; 80a, an outer end; 90. a rim line.