JPH089284B2 - Radial tire and rim assembly for four-wheeled vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-wheeled vehicle capable of preventing the bead portion from coming off the rim even when the internal pressure of the tire is reduced due to a flat tire or a burst due to nailing or when the internal pressure is reduced or during sharp cornering. For radial tire and rim assembly for vehicle.

[0002]

2. Description of the Related Art Radial tires have lower rigidity in the radial direction of tires than cross-ply tires. Therefore, sufficient consideration is required.

Also, four-wheeled vehicles such as passenger cars, ATVs, trucks and buses, that is, so-called four-wheeled vehicles including three-wheeled vehicles that turn without tilting the tires, except for motorcycles in which the tire tilts when turning and camber thrust acts. Even with the tires used, it is required to prevent accidents during punctures or bursts.

[0004] In this four-wheeled vehicle tire, a tire with a safety device, in which a support made of an elastic body or the like is arranged inside the tire, and a ring having an independent airtight chamber inside the tire have hitherto been used A double-diaphragm structure tire in which a body is arranged, a reinforced tire in which a sidewall or a shoulder portion is reinforced by an elastic reinforcing layer provided inside thereof, and the like are known.

However, the former two problems are not suitable for high-speed tires because of a large increase in weight, and there is a problem that the manufacturing cost increases. In addition, the latter is insufficient in load bearing capacity, is inferior in function as a safety tire, and tends to impair tire dynamic performance such as riding comfort and steering performance during normal traveling.

[0006] The present inventors show the same good riding comfort and steering stability as ordinary tires during normal running, and
We are developing various radial tires for four-wheeled vehicles that can continue to run safely even if the internal pressure drops sharply due to punctures.

On the other hand, the holding force of the tire on the rim has hitherto been
The pressing force on the bead seat at the bead portion due to the tire internal pressure and the frictional force therebetween were the main ones.

[0008]

However, this holding force becomes smaller as the tire internal pressure decreases. When the tire suddenly turns when the internal pressure suddenly drops, such as during puncture, the lateral force associated with the turning movement, that is, the camper thrust, acts on the tire, causing the bead part of the tire to disengage from the bead seat of the rim and inside the well for mounting the tire. Fall into. As a result, the tire may come off the rim completely and cause a serious accident.

Explaining the rim disengagement of the bead portion of the tire further, the lateral force generated during cornering moves the tread portion laterally with respect to the rim. As a result, in the vicinity of the ground contact portion of the tire, a force in the tire axial direction (lateral direction),
A rotational moment centered on the bead occurs. This rotational moment raises the heel of the bead portion because the tire internal pressure is low as described above, and reduces the frictional force between the bead portion and the bead seat, which is the holding force of the tire. As a result, the bead portion displaces the tapered bead seat inward in the tire axial direction.

Further, since the tension of the bead core is reduced due to this displacement, the holding force is abruptly reduced, so that the bead portion falls into the well.

Therefore, the present invention sets the width and height of the tread portion of the radial tire for a four-wheeled vehicle within a predetermined range,
In addition, while the toe portion extending inward in the tire radial direction is provided in the bead portion, the bead portion is basically formed even if a lateral force acts when the internal pressure decreases while providing an annular groove in the rim that fits with the toe portion. The purpose of the present invention is to provide an assembly of a radial tire for a four-wheeled vehicle (hereinafter referred to as a radial tire) and a rim, which can prevent the vehicle from falling into the well and continue traveling safely.

[0012]

SUMMARY OF THE INVENTION The present invention is an assembly comprising a radial tire for a four-wheeled vehicle and a wheel rim having a well for mounting the tire, the radial tire comprising a pair of non-extensible bead cores. A bead portion, a carcass extending between the bead portions and having both ends rewound around the bead core and locked, a bead apex disposed between the rewound portion and the carcass body, and a tire radial outside of the carcass. And a belt layer having cords arranged between the carcass and the tread portion and arranged at a shallow angle with respect to the tire circumferential direction, and is defined by tire sectional height / tire maximum width. The flatness is 60% or less, and the tread portion has an axial width that exceeds the maximum width of the carcass, and the end portion of the tread portion has the carcass. Together located 50 to 100% of the section height, at least one of the bead portions,
The toe portion extending axially inward and radially inward of the bead core and a hump groove formed on the tire axially outer side of the toe portion, while the rim has an annular groove for receiving the tip of the toe portion. and with comprising a hump to the hump groove and the fitting, the Bidoepe'
Kusu has a height ho of 40 to 11 at the end of the tread portion.
For four-wheeled vehicles characterized by extending to 0% range
Is a radial tire and rim assembly.

[0013]

The tire has an aspect ratio defined by tire cross-section height / tire maximum width of 60% or less, and the tread portion has an axial width exceeding the maximum width of the carcass, and the end thereof. The part is 50 to 100 of the sectional height of the carcass.
%, The rigidity of the tread portion is high, the bending point is above the side wall portion, and even when the internal pressure of the tire is low, the running safety is improved compared to a normal tire. Furthermore, since the toe part and hump groove are formed on the tire and the annular groove and hump are provided on the rim, it is possible to effectively prevent the rim from coming off when the internal pressure drops in a tire for a four-wheeled vehicle, and to improve driving safety. Can improve. See you again
-The pex is 40 to 110 at the height of the end of the tread.
When the tire's internal pressure drops, it extends to the range of
The lateral rigidity of the tires can be maintained and driving safety is further enhanced.
Can be raised.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An assembly of a radial tire and a rim according to the present invention will be described below, taking a case where the radial tire is a passenger vehicle tire as an example, and an embodiment thereof will be described with reference to the drawings.

A radial tire (hereinafter referred to as a radial tire or tire) 1 for a four-wheeled vehicle has a rewinding mechanism in which a bead core is rewound from a tread portion 6 to a bead core 3 of a bead portion 2 through a sidewall portion. Part 4
A carcass 4 including a ply in which A is integrally provided and cords are radially arranged, a rewinding portion 4A, and a carcass main body portion 4
And a belt layer 7 having a cord arranged inside the tread portion and outside in the tire radial direction of the carcass and arranged at a shallow angle with respect to the tire circumferential direction. .

The tire 1 is a radial tire for four-wheeled vehicles except for two-wheeled vehicles, and the tread surface of the tread portion 6 is flat.

The tire 1 has a flatness ratio of 60% or less defined by tire cross-sectional height / tire maximum width in order to improve lateral rigidity and enhance safety. Note that the lower limit is naturally determined by those skilled in the art as long as it is a tire.

The carcass 4 has at least one layer of carcass ply without radial arrangement cords, and both ends thereof are wound around the bead core 3 by being rewound from inside to outside in the tire axial direction and locked. ing.

One feature of the tire 1 is that the tread portion 6 extends to a portion where the sidewall portion having a small thickness is formed in the conventional tire.

As a result, the axial width TW of the tread portion 6 exceeds the maximum width L of the carcass 4.

Further, the height ho of the tread end P, which is the end of the tread portion 6 in the tire axial direction, is set within the range of 50 to 100% of the sectional height h of the carcass 4.

In the present specification, each height means a radial distance with respect to the heel end J.

Further, the thickness at the tread end P of the tread portion 6 is the wall thickness CW at the center of the tread and the wall thickness NW at a position 3/4 of the maximum width L of the carcass 4 from the center of the tread.
And an average value of 70 to 200%. When the wall thickness is less than 70%, when the tire internal pressure decreases, the rigidity is insufficient and safe running cannot be maintained. Again 200
If it exceeds%, heat generation during high-speed running becomes severe, which is not preferable.

The thickness at the tread end P is set on the basis of the average value of the wall thickness CW at the tread center and the wall thickness NW at a position 3/4 of the maximum width L of the carcass 4 from the tread center. Is to balance the thickness of the tread as a whole.

With such a structure, a difference in rigidity acting as a hinge is formed between the tread portion and the side wall portion, and when the internal pressure of the tire decreases as shown in FIG. Bends in the tread portion 6
Can be flattened overall and ensure safe driving.

The tread portion 6 is, as shown in FIG.
A lug pattern or a block pattern having a high heat dissipation effect in order to suppress the temperature rise of the tread portion 6 due to heat generation at both end portions 6A outside the grounding area that comes into contact with the road surface when the rim is assembled and a normal internal pressure and a normal load are applied. Is adopted, and sipes or narrow grooves S are formed.

The sipes or the narrow grooves S are the treads described above.
5 to 20 of the curve distance TL of the surface of the tread portion 6 from the end P
%, The interval is 5 to 20 mm, and the width is 0.1 to 5 mm. When the angle is 45 to 90 with respect to the tire circumferential direction, heat generation can be suppressed, and the angle is 0 to 45.
In case of °, not only the heat generation but also the vertical spring constant can be lowered and the riding comfort can be improved.

The belt layer 7 has cords arranged between the carcass 4 and the tread portion 6 and arranged at a shallow angle with respect to the tire circumferential direction. Further, in this example, the cord includes an organic fiber cord having a low elastic modulus and a fiber cord having a high elastic modulus, and forms plies 7A, 7B and ply 7C, respectively.

The width of the belt layer 7, that is, the ply 7 in this example.
The widths of A and 7B are the curve distance TL of the surface of the tread portion 6
Is set in the range of 70% to 100%.

Therefore, even if the tread portion 6 is flattened when the internal pressure is reduced, the belt layer 7 extends to both ends of the tread portion 6 to enhance the reinforcing effect in this region and enable long-term continuous running. .

As the low elastic modulus organic fiber cord, for example, nylon, polyester, rayon or the like having an elastic modulus of 1000 kg / mm ² or less is preferably used.
The reason why the organic fiber cord is preferably used is that the crown portion and the shoulder portion or the side portion have different radii of curvature. This is because the effect can be achieved with the same ply.

As the fiber cord having a high elastic modulus, a fiber having a high elastic modulus such as aramid or steel is used. In addition, ply 7C made of this high elastic fiber cord
Is set to 80% or less of the maximum width L of the carcass 4 for the above reason.

Each bead portion 2 is a non-stretchable bead core 3
A bead apex 5, a toe portion 9 extending inward in the tire radial direction, and a hump groove 10.

The bead core 3 is characterized in that it is located on the outer side in the tire axial direction as compared with the conventional tire. The distance W4 from the center of the bead core 3 to the heel end J is the heel end J to the toe end. 1 / 2.5 to 1 of distance W6 to N
/7.6, preferably in the range of 1 / 2.9 to 1 / 6.3. In the case of a conventional tire, it is about 1 / 2.2 at most. The heel end J is defined as the intersection of the extension lines of the outer surface Q and the bottom surface M of the bead portion 2.

By reducing the distance W4 as in this example, the bead core 3 can be brought closer to the rim flange 25 described later, and the fitting with the rim 20 can be further strengthened.

The bead apex 5 is JIS
(A) It is made of rubber having a hardness of 74 to 95 °, is arranged between the carcass body 4B and its winding portion 4A, and extends from the bead core 3 toward the outer side in the tire radial direction. And the outer end thereof is located in the range of 40 to 110%, particularly preferably 70 to 90% of the height ho from the base of the carcass to the end P of the tread portion 5. If it exceeds 110%, the hinge action will not be exhibited, which is not preferable. As a result, the lateral rigidity of the tire when the internal pressure of the tire is reduced can be maintained and safe driving can be performed.

The toe portion 9 projects inward in the tire radial direction from the bottom surface M of the bead portion 2 on the inner side of the bead core 3 in the tire axial direction, and the projecting amount L is arbitrary depending on the application and size of the applied tire. Can be selected. The toe portion 9 is relatively hard, for example, JIS (A) hardness is 70 to
It is formed by rubber in the range of 85 °.

The hump groove 10 is formed on the outside of the toe portion 9 in the tire axial direction and extends in the tire circumferential direction. A distance W5 between the hump groove 10 and the heel end J in the tire axial direction is set to a range of 2.1 to 4.8 times the distance W4 from the heel end J to the center of the bead core 3. By comprising the hump groove 10, a radial tire 1 of the present embodiment, Suruga suitable for fitting between the rim 20 forming a hump 23 to be described later, it can be applied similarly to the rim without the hump 23.

The rim 20 has a well 21 for mounting a tire formed in the center thereof, and an annular groove 22, a hump 23, a bead seat 24, and a rim flange 25 are sequentially formed on both sides of the well 21.

The annular groove 22 is formed adjacent to the well 21 and extends in the tire circumferential direction. Therefore, a protrusion 26 extending in the circumferential direction is formed inside the annular groove 22, and the height h1 thereof is preferably 5 mm from the bead seat 24.
Set as follows. Note that this also includes setting the height h1 to be minus, that is, setting the protrusion 26 to be the bead seat 24 or less.

Further, the groove bottom of the annular groove 22 needs to be located inward of the bead seat 24 in the tire radial direction,
The depth d is preferably set to 10 mm or less from the bead seat 24. The innermost end of the annular groove 22 in the tire radial direction, that is, the distance W3 in the tire axial direction between the deepest portion and the bead seat end H is W6 / W3 = 0.7 to W6.
It is set to satisfy the condition of 1.2. The bead seat end H is defined as the intersection of the extension lines of the bead seat 24 and the inner surface of the rim flange 25.

The hump 23 has a distance W2 in the tire axial direction between the outermost end in the tire radial direction and the bead seat end H.
Is set to satisfy the condition of W5 / W2 = 0.5 to 1.2 with respect to W5. Also, the height h of the hump 23
2 is preferably 5 mm or less from the bead seat 24.

The bead seat 24, as shown in FIG.
Has a taper of a certain angle (α) with respect to the tire axial direction,
The radius decreases toward the inner side in the tire axial direction. It is also possible to use an inverse taper.

For the width W1 of the bead seat 24, the dimensions of various rims that have been standardized in the past are used. As a result, the rim 20 can be used not only for the tire 1 of the present invention that employs the above-described special structure but also for a tire having a conventional structure.

The shapes and dimensions of the toe portion 9 and the hump groove 10 and the annular groove 22 and the hump 23 of the rim 20 are as follows.
The rim diameter D defined at the bead seat end H, the hump diameter Da of the hump 23, and the groove bottom diameter of the annular groove 22 shown in FIG. Db and the projection diameter Dc of the projection 26 are

-3.0 mm≤D-Da≤ + 5.0 mm +2.0 mm≤D-Db≤ + 20 mm 0.0 mm≤D-Dc≤ + 5.0 mm and Da> Dc> Db It is desirable to set.

By setting the hump diameter Da> the projection diameter Dc, the tire bead portion can be easily attached.

[0048]

As described above, in the radial tire and rim assembly of the present invention, the radial tire is provided with the toe portion extending inward in the tire radial direction, and the rim is provided with the annular groove for fitting with the toe portion. Therefore, the holding force between the tire and the rim can be increased, and even if a lateral force acts when the internal pressure decreases, the rim does not come off and the vehicle can continue to run safely.

Further, since the radial tire is provided with the hump groove and the rim is provided with the hump which fits into the hump groove, the holding force can be increased and more safe running can be achieved. The above-mentioned bead portion structure can be applied to only one bead portion.

[Brief description of drawings]

FIG. 1 is a right half sectional view showing an example of a radial tire used in the present invention.

FIG. 2 is a perspective sectional view of the radial tire.

FIG. 3 is a cross-sectional view schematically showing an internal pressure lowering state of an embodiment of an assembly of a radial tire and a rim of the present invention.

FIG. 4 is an exploded partial sectional view of the assembly of the radial tire and the rim.

[Explanation of symbols]

 2 bead part 3 bead core 4 carcass 5 bead apex 6 tread part 7 belt layer 9 toe part 10 hump groove 20 rim 22 annular groove 23 hump

Claims (6)

[Claims] 1. An assembly composed of a radial tire for a four-wheeled vehicle and a wheel rim having a well for mounting a tire, wherein the radial tire has a pair of bead portions having a non-extensible bead core and a space between the bead portions. A carcass which extends and has both ends rewound around the bead core to be locked, a bead apex arranged between the rewound part and the carcass body, a tread part arranged on the tire radial outside of the carcass, and A belt layer having cords arranged between the carcass and the tread portion at a shallow angle with respect to the tire circumferential direction, and having a flatness ratio defined by tire cross-sectional height / tire maximum width of 60% or less. Moreover, the tread portion has an axial width exceeding the maximum width of the carcass, and its end portion has a cross-sectional height of 50 to 100 of the carcass. And at least one of the bead portions has a toe portion extending inward in the axial direction and radially inward of the bead core and a hump groove formed on the outer side in the tire axial direction of the toe portion. the rim, with comprises a hump that mates with the annular groove and the hump groove receiving a leading end of said toe portion, the bead apex, a high end of the tread portion
A radial tire and rim assembly for a four-wheeled vehicle, characterized in that it extends to a range of 40 to 110% of ho . 2. The tread portion has a wall thickness at an end thereof which is 3 / the maximum thickness of the carcass from the center portion and the center portion.
4. The four-wheeled vehicle according to claim 1, wherein the average value of the wall thickness at position 4 is 70 to 200%.
Radial tire and rim assembly for the car. 3. The four-wheeled vehicle according to claim 1, wherein the width of the belt layer is in the range of 70 to 100% of the curved distance of the surface of the tread portion.
Radial tire and rim assembly for the car. 4. The belt layer has an elastic modulus of 100 kg / mm ²
The radial tire and rim assembly for a four-wheeled vehicle according to claim 1, 2 or 3, further comprising at least one ply comprising the following organic fiber cord. 5. The four-wheel vehicle according to claim 1 , 2, 3 or 4 , wherein the tread portion has a sipe formed in the tire circumferential direction or the tire rotation axis direction.
Radial tire and rim assembly for motor vehicles . 6. The bead core has a distance W4 from the center to the heel end and a distance W6 from the heel end to the toe end.
6. The radial tire and rim set for a four-wheel vehicle according to claim 1, 2, 3, 4 or 5 , characterized in that it is formed in the range of 1 / 2.5 to 1 / 7.6. Three-dimensional.