CN110962509A

CN110962509A - Run-flat tire

Info

Publication number: CN110962509A
Application number: CN201911368486.3A
Authority: CN
Inventors: 方晓云; 纵封成
Original assignee: Cheng Shin Tire and Rubber China Co Ltd
Current assignee: Cheng Shin Tire and Rubber China Co Ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2020-04-07

Abstract

The invention relates to a run-flat tire, which comprises a tread part, and two groups of sidewall parts and tire beads which are respectively arranged on two sides of the tread part, wherein the sidewall parts and the tire beads are sequentially arranged on the side edges of the tread part; the tire bead comprises a bead core and a sizing material arranged at the bottom, and the inner diameter Di of the bead core and the diameter Dh of the convex peak of the rim meet the condition that Di-Dh is more than or equal to 2.0mm and less than or equal to 4.5 mm; when the tire and the rim are in an installation state, the bottom of the tire bead is positioned in a rim groove of the rim, the rubber material at the bottom of the tire bead is in a compressed state, and the ratio of the sectional area of the rubber material in the compressed state along the radial section of the tire to the sectional area of the rubber material in the free state along the radial section of the tire is 49-60%. The mounting stability between the tire and the rim can be improved while the assembly process of the tire and the rim is improved, the tire bead is prevented from being knocked off or the rim is prevented from sliding when the run-flat tire runs in a run-flat state, particularly turns, and the safety is improved.

Description

Run-flat tire

Technical Field

The invention relates to the technical field of tires, in particular to a run-flat tire.

Background

The run-flat tire can still run for 80km at the speed of less than 80km/h under the condition of pressure loss; and the tire can support the whole vehicle to run safely by using the high-strength sidewall reinforcing rubber under the normal condition that the tire bead does not fall off the ring without changing the tire. Under the condition of pressure loss, in order to prevent the run-flat tire from knocking off and ensure the driving stability of the vehicle, the vehicle is provided with a special tire burst-proof Rim (EH2& EH2+ Rim), and compared with a common Rim, the vehicle is characterized in that the design of a Rim Hump (Rim Hump) is higher than that of the common Rim; because the side wall strength of the run-flat tire is stronger, the assembly of the tire and the rim is difficult, if the tire bead adopts the conventional design, the interference between the bead heel and the rim hump is too large, the assembly is more difficult and the embedding is difficult, and meanwhile, the risk of assembling and tire burst is caused by too large inflation embedding pressure.

The conventional method for improving the difficulty of assembly is to enlarge the inner circumference of the bead, so that the assembly process can be improved, but the compression amount of the bead bottom rubber is too small, so that the installation stability between the tire and the rim in the installation state is poor, and even the risk of the run flat tire being knocked off or slipping the rim due to the lateral force applied during turning can be caused.

Therefore, how to improve the assembling process of the tire and the rim, improve the stability of the installation between the tire and the rim, ensure that the tire bead of the run-flat tire is prevented from being knocked off or the rim is prevented from sliding when the run-flat tire runs in a run-flat state, particularly turns, and improve the safety is a technical problem to be solved by the technical personnel in the field.

Disclosure of Invention

The invention aims to provide a run-flat tire, which can improve the assembly process of the tire and a rim, improve the mounting stability between the tire and the rim, ensure that the bead of the tire is prevented from being knocked off or the rim is prevented from sliding when the run-flat tire runs in a run-flat state, particularly turns, and improve the safety.

In order to solve the technical problem, the invention provides a run-flat tire, which comprises a tread part, and two groups of sidewall parts and tire beads, wherein the two groups of sidewall parts and the two groups of tire beads are respectively arranged on two sides of the tread part; the tire bead comprises a bead core and a sizing material arranged at the bottom, and the inner diameter Di of the bead core and the diameter Dh of the convex peak of the rim meet the condition that Di-Dh is more than or equal to 2.0mm and less than or equal to 4.5 mm; when the tire and the rim are in a mounted state, the bottom of the bead is positioned in a rim well of the rim, the rubber material at the bottom of the bead is in a compressed state, and the ratio of the sectional area of the rubber material in the compressed state along the radial section of the tire to the sectional area of the rubber material in the free state along the radial section of the tire is 49-60%.

The Di-Dh value is limited, so that the problem of overlarge embedding pressure during assembly of the tire and the rim is solved, meanwhile, the compression ratio of the rubber material at the bottom of the tire bead before and after installation is limited, enough rubber material at the bottom of the tire bead can be guaranteed, the tire and the rim can be stably matched in the installation state, synchronous rotation of the tire and the rim is guaranteed, the tire bead ring is prevented from being knocked off or the rim slides when the tire and the rim run flat under the condition of run flat, particularly during turning, and safety is improved.

Optionally, the bead bottom is provided with a guiding surface with a diameter gradually decreasing from outside to inside.

Optionally, the guide surface is a one-piece inclined surface, and an included angle α between the inclined surface and the axial direction of the tire satisfies 16.5 DEG- α -17.5 deg.

Optionally, the guide surface comprises a first section of inclined surface and a second section of inclined surface which are arranged from outside to inside, an included angle β between the first section of inclined surface and the axial direction of the tire is more than or equal to 8.6 degrees and less than or equal to β and less than or equal to 9.7 degrees, and an included angle gamma between the second section of inclined surface and the axial direction of the tire is more than or equal to 16.5 degrees and less than or equal to gamma and less than or equal to 17.5 degrees.

Optionally, the width of the first segment of the inclined surface in the axial direction of the tire is not more than 10 mm.

Optionally, a width B of the bead core in the axial direction of the tire and a groove bottom width M of the rim well satisfy: B/M is more than or equal to 64 percent and less than or equal to 69 percent.

Optionally, in the mounted state, the width of the bead bottom along the axial direction of the tire is L, the distance between the convex peak and the side wall of the wheel rim groove far away from the convex peak is E, and L/E is more than or equal to 72% and less than or equal to 100%.

Optionally, the inner diameter Di of the bead core and the diameter Db of the bead root satisfy: Di-Db is more than or equal to 2.5mm and less than or equal to 5 mm.

Drawings

FIG. 1 is a cross-sectional view of a run-flat tire provided by an embodiment of the present invention;

FIG. 2 is a schematic structural view of the tire before installation with a rim;

FIG. 3 is a schematic structural view of the tire and rim in a mounted state;

FIG. 4 is a schematic structural view of the inclined surface of the bead bottom in a one-step structure;

fig. 5 is a schematic structural view showing a structure in which the inclined surface of the bead bottom is two-step.

In the accompanying fig. 1-5, the reference numerals are illustrated as follows:

1-a tread portion; 2-sidewall portions; 3-bead, 31-bead core, 32-compound, 33-bead root, 34-inclined plane, 351-first segment inclined plane, 352-second segment inclined plane; 4-gas retention layer; 5-a ply layer; 6-filling glue; 7-sidewall reinforcing rubber; 8-rim, 81-hump, 82-well;

di-inner diameter of bead core;

dh-the diameter of the hump;

db-bead root diameter;

α -the angle between the inclined surface and the axial direction of the tire;

β -angle between the first inclined plane and the axial direction of the tire;

gamma-the included angle between the second section inclined plane and the axial direction of the tire;

b-the length of the bead core in the axial direction of the tire;

m-the groove bottom width of the wheel felloe groove;

l-the length of the bead bottom in the axial direction of the tire;

the distance between the E-peak and the side wall of the wheel well far away from the peak.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1-5, fig. 1 is a cross-sectional view of a run-flat tire according to an embodiment of the present invention; FIG. 2 is a schematic structural view of the tire before installation with a rim; FIG. 3 is a schematic structural view of the tire and rim in a mounted state; FIG. 4 is a schematic structural view of the inclined surface of the bead bottom in a one-step structure; fig. 5 is a schematic structural view showing a structure in which the inclined surface of the bead bottom is two-step.

An embodiment of the present invention provides a run-flat tire, as shown in fig. 1, including a tread portion 1, and two sets of a sidewall portion 2 and a bead 3 respectively disposed on two sides of the tread portion 1, where the sidewall portion 2 and the bead 3 are sequentially disposed on the side of the tread portion 1, that is, on two sides of the tread portion 1, and each side is sequentially disposed with the sidewall portion 2 and the bead 3, where the bead 3 is configured to cooperate with a rim 8. Specifically, the bead 3 comprises a bead core 31 and a rubber compound 32 arranged at the bottom of the bead 3, the inner diameter Di of the bead core 31 and the diameter Dh of the convex peak 81 of the rim 8 meet the condition that Di-Dh is more than or equal to 2.0mm and less than or equal to 4.5mm, wherein as shown in FIG. 2, the inner diameter Di of the bead core 31 refers to the diameter of the inner end of the bead core 31 along the radial direction of the tire, and the diameter Dh of the convex peak 81 of the rim 8 refers to the maximum diameter of the convex peak 81 of the rim 8. If the value of Di-Dh is too small, there is a problem that the fitting pressure (air pressure when the tire bead 3 is inflated to the extent that it crosses the bead 81 of the rim 8 when the tire is assembled with the rim 8) is too large during the assembly of the tire with the rim 8, and if the value of Di-Dh is too large, although the assembly process of the tire and the rim 8 can be improved, in the case of run-flat running, particularly, in the case of cornering, the tire bead 3 is likely to be unseated or the rim 8 is likely to slip, where unseating means that the tire bead 3 is unseated from the rim groove 82 and the rim 8 slips means that the rim 8 and the tire slide relative to each other when the rim 8 rotates, and the rotation of the two is not synchronized.

When the tire and the rim 8 are in an installation state, the bottom of the bead 3 is positioned in the wheel felloe groove 82 of the rim 8, at this time, the rubber 32 at the bottom of the bead 3 is in a compressed state, the cross section area of the rubber 32 at the bottom of the bead 3 in the compressed state along the radial section of the tire (namely the cross section area of the rubber 32 at the bottom of the bead 3 shown in fig. 3) is S1, the cross section area of the rubber 32 at the bottom of the bead 3 in the free state along the radial section of the tire (namely the cross section area of the rubber 32 at the bottom of the bead 3 shown in fig. 2) is S2, and the compression ratio S1/S2 of the rubber 32 meets the conditions that S1 is more than or equal. So set up, can guarantee the effort between sizing material 32 and the rim 8 under the installation condition, make the cooperation between the two stable, avoid under the circumstances that the run flat traveles, the circumstances that appears tire bead 3 knockover or rim 8 and slide.

That is, in the present embodiment, the value of Di-Dh is defined to solve the problem of excessive fitting pressure when the tire is assembled with the rim 8, and the compression ratio S1/S2 before and after the installation of the rubber compound 32 at the bottom of the bead 3 is defined to ensure that the rubber compound 32 at the bottom of the bead 3 is sufficient, so that the tire and the rim 8 can be stably fitted in the installed state, the two can be rotated synchronously, and the tire bead 3 is prevented from knocking over or slipping the rim 8 during run-flat running, particularly during cornering, and the safety is improved.

In addition, in this embodiment, the inner side of the sidewall 2 is further provided with an air-retention layer 4, the inside of the sidewall 2 and the bead 3 is provided with a carcass layer 5, both ends of the carcass layer 5 respectively wind around the bead core 31 and turn over outwards and are located at the sidewall 2, the bead core 31 is a multi-strand steel wire arranged along the circumferential direction of the tire, the inside of the two carcass layers 5 is further provided with filling rubber 6, a sidewall reinforcing rubber 7 is further arranged between the inner side of the two carcass layers 5 and the air-retention layer 4, the outer side and the bottom of the carcass layer 5 are both provided with rubber 32, and in the installation state, the rubber 32 located at the bottom is located in the rim. In the present embodiment, the rubber compound 32 located at other positions (e.g., the filler rubber 6 in the two plies 5, the rubber compound 32 provided at the side of the plies 5, etc.) is not changed, and therefore, the description of the rubber compound 32 provided at the bottom of the bead 3 will be focused on in the present embodiment.

In the above embodiment, the bottom of the bead 3 is provided with a guiding surface, and the diameter of the guiding surface gradually decreases from outside to inside, that is, the diameter of the bottom of the bead 3 gradually decreases from outside to inside, wherein inside refers to the side facing the inside of the tire, that is, the side between the two sidewall portions 2 (bead 3), and correspondingly, outside refers to the side facing the outside of the tire, that is, the side outside the two sidewall portions 2 (bead 3), and the guiding surface is arranged to provide a guiding function when the tire and the rim 8 are assembled in a fitting manner, thereby facilitating the assembling process between the tire and the rim 8. Specifically, the guiding surface may be a one-stage structure or a two-stage structure, and the one-stage structure and the two-stage structure are described in detail below.

When the guide surface at the bottom of the tire bead 3 is of a one-section structure, as shown in fig. 4, the guide surface is an inclined surface 34 with the diameter gradually decreasing from outside to inside, and an included angle α between the inclined surface 34 and the axial direction of the tire is equal to or larger than 16.5 degrees and equal to or smaller than α and equal to or smaller than 17.5 degrees, so that the bottom of the tire bead 3 can be ensured to have enough rubber 32, and in the installation state, the combination of the rubber 32 at the bottom of the tire bead 3 and the rim groove 82 is ensured to be tighter, so that the anti-falling performance of the tire bead 3 is improved, and meanwhile, the sealing performance between the tire and the rim 8 is also improved, namely, the air retention performance of.

When the guiding surface at the bottom of the tire bead 3 is of a two-section structure, as shown in fig. 5, the guiding surface body comprises a first section inclined surface 351 and a second section inclined surface 352 which are arranged from outside to inside, wherein an included angle between the first section inclined surface 351 and the axial direction of the tire is β, an included angle between the second section inclined surface 352 and the axial direction of the tire is gamma, and the inclined angle of the two sections of inclined surfaces satisfies that the angle is more than or equal to 8.6 degrees and less than or equal to β and less than or equal to 9.7 degrees and the angle is more than or equal to 16.5 degrees and less than or equal to 17.5 degrees.

Alternatively, in the present embodiment, the bottom of the bead 3 may be inclined in three or more stages, and the single-stage structure and the two-stage structure may simplify the manufacturing process of the tire.

Further, when the spigot surface of tire bead 3 bottom is two segmentation structures, the first section inclined plane 351 that is located the outside is not more than 10mm at the axial width of tire, so set up, can guarantee that the second section inclined plane 352 that is located the inboard is enough at the axial width of tire, and then guarantee that the sizing material 32 of tire bead 3 bottom is enough, make under the installation, guarantee that the sizing material 32 of tire bead 3 bottom combines with rim groove 82 more closely, both improved the anti-falling nature of tire bead 3, the leakproofness between tire and rim 8 has also been promoted simultaneously, the air-tight nature of tire has been promoted promptly.

In the above embodiment, the width B of the bead core 31 in the axial direction of the tire and the groove bottom width M of the rim well 82 satisfy 64% ≦ B/M ≦ 69%. So set up for bead core 31 has sufficient structural strength, makes the tire bead 3 bottom can stably cooperate with rim groove 82, has both improved the anti-dropoff nature of tire bead 3, has also promoted the air retention of tire simultaneously.

In the above embodiment, in the mounted state, the width of the bottom of the bead 3 in the axial direction of the tire is L, the distance between the bead 81 of the rim 8 and the side wall of the rim well 82 away from the bead 81 is E, and L/E is 72% to 100%. So set up, can guarantee under the installation state, bead 3 bottom is located rim groove 82, and hump 81 can play spacing effect to bead 3 bottom, has improved bead 3's anti dropout nature.

In the above embodiment, the inner diameter Di of the bead core 31 and the diameter Db of the bead root 33 satisfy 2.5 mm. ltoreq. Di-Db. ltoreq.5 mm. The bead root 33 is the intersection point between the outer edge of the rubber 32 at the bottom of the bead 3 and the inclined surface 34 arranged on the bottom surface, so that the bottom of the bead 3 can be ensured to have enough rubber 32 to ensure that the rubber is stably matched with the rim groove 82, the assembly process of the tire and the rim 8 is improved, and the problem of overlarge embedding pressure is avoided.

In summary, the tire provided by the present embodiment solves the problem of excessive fitting pressure when the run-flat tire is assembled with the rim 8 by defining the difference between the inner diameter Di of the bead core 31 and the diameter Dh of the hump 81 of the rim 8, and ensures perfect matching between the bead 3 and the rim well 82, prevents the bead 3 from knocking over or the rim 8 from slipping, and improves the air-retention property of the run-flat tire by defining the contour shape of the bottom of the bead 3 and the compression ratio of the rubber 32 at the bottom of the bead 3 before and after assembly.

In addition, in the present embodiment, for convenience of explanation and understanding, the tire radial direction and the tire axial direction are designated in correspondence in each drawing.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.

Claims

1. The run-flat tire is characterized by comprising a tread part (1), and two groups of side parts (2) and tire beads (3) which are respectively arranged at two sides of the tread part (1), wherein the side parts (2) and the tire beads (3) are sequentially arranged at the side edges of the tread part (1);

the tire bead (3) comprises a tire bead core (31) and a rubber material (32) arranged at the bottom, and the diameter Dh between the inner diameter Di of the tire bead core (31) and the diameter Dh of a convex peak (81) of the rim (8) meets the requirement that Di-Dh is more than or equal to 2.0mm and less than or equal to 4.5 mm;

when the tire and a rim (8) are in a mounted state, the bottom of the bead (3) is positioned in a rim well (82) of the rim (8), a rubber material (32) at the bottom of the bead (3) is in a compressed state, and the ratio of the sectional area of the rubber material (32) along the radial section of the tire in the compressed state to the sectional area of the rubber material (32) along the radial section of the tire in a free state is 49-60%.

2. Run-flat tyre according to claim 1, characterized in that the bottom of the bead (3) is provided with a guiding surface of decreasing diameter from the outside to the inside.

3. Run-flat tyre according to claim 2, characterized in that said guiding surface is a one-piece inclined surface (34), the angle α between said inclined surface (34) and the axial direction of the tyre satisfying 16.5 ° ≦ α ≦ 17.5 °.

4. The run-flat tire according to claim 2, wherein the guide surface comprises a first stage inclined surface (351) and a second stage inclined surface (352) arranged from outside to inside, an angle β between the first stage inclined surface (351) and the axial direction of the tire satisfies 8.6 ° ≦ β ≦ 9.7 °, and an angle γ between the second stage inclined surface (352) and the axial direction of the tire satisfies 16.5 ° ≦ γ ≦ 17.5 °.

5. Run-flat tyre according to claim 4, characterized in that the first segment of inclined surface (351) has a width in the axial direction of the tyre not greater than 10 mm.

6. The run-flat tire according to any one of claims 1 to 5, wherein a width B of the bead core (31) in the axial direction of the tire and a groove bottom width M of the rim groove (82) satisfy 64% ≦ B/M ≦ 69%.

7. Run-flat tyre according to anyone of claims 1 to 5, characterized in that the width of the bottom of said beads (3) in the axial direction of the tyre in the mounted condition is L and the distance between said hump (81) and the side wall of said well (82) remote from said hump (81) is E72% ≦ L/E ≦ 100%.

8. Run-flat tire according to any one of claims 1 to 5, wherein the inner diameter Di of the bead core (31) and the diameter Db of the bead root (33) satisfy: Di-Db is more than or equal to 2.5mm and less than or equal to 5 mm.