JP3213061B2 - Tire-rim assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire-rim assembly providing excellent uniformity of wheels, and more particularly to a rim, a deep rim, a wide deep rim, and other standards specified by JATMA and the like. Improves the uniformity of the wheels assembled on the rim (hereinafter referred to as "standard rim"), reduces radial runout (hereinafter "RRO"), and effectively suppresses radial force variation (hereinafter "RFV") Things.

[0002]

2. Description of the Related Art Conventionally, in order to reduce the RFV of a wheel, the RFV of the tire itself is measured over its entire circumference, and the position where the measured value is the maximum is determined by the outer circumferential runout of the rim on which the tire is assembled. Rim assembly has been widely and generally performed in accordance with the smallest position of the rim.

[0003]

However, in recent years, the rim processing accuracy has been greatly improved, and the RFV of the wheel cannot be effectively reduced even with the above-described method. Of the wheel RFV,
Often, the difference between the maximum and the minimum is greater than a similar difference in the RFV of the tire itself.

[0004] This means that even if a tire having a good RRO is mounted on a rim having high processing accuracy, the RRO as a wheel does not become small.
It is thought that the cause is eccentric mounting when assembling the tire rim. That is, in the conventional tire-rim assembly, when assembling the tire into the rim, the outer surface of the bead portion 21 and the rounded concave portion 23 of the rim 22 are arranged as illustrated in FIG.
And a relatively large gap 25 is generated between the portion extending over the curved flange 24 and the position and size of the gap 25 are variously changed in the tire circumferential direction,
This is considered to be a major factor in the deterioration of the RRO of the wheel.

[0005] Therefore, such a gap 25, so you decrease the variation in the tire circumferential direction, in JP-A 3-189201 discloses measures the RRO in the shoulder portion of the wheel at a circumferential on, the value A spacer is interposed between the bead portion of the tire and the flange of the rim at a large location, but according to this, it is necessary to repeat the rim assembly and the internal pressure filling operation, which increases workability. In addition to the bad,
When a large external force acts on the wheel, there is a problem that the relative position between the tire and the rim changes, and the wheel needs to be corrected again.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and has been made in connection with the assembling of a tire to a rim, particularly, a tire bead portion and a rim of a rim. To provide a tire-rim assembly capable of realizing concentric mounting of tires, increasing the uniformity of wheels, and effectively reducing the RFV of the wheels by preventing a gap from being formed between the corner round recesses. Things.

[0007]

SUMMARY OF THE INVENTION A tire-rim assembly according to the present invention comprises an inclined bead seat, a rounded concave portion successively extending outwardly in the width direction of the inclined bead seat, and a curved flange which recurs outward. A rim of a standard rim comprising a bead portion of a tire tightly fitted to the inclined bead seat, wherein the bead portion is in contact with a curved flange of the rim and a bead portion outer surface facing the rim. Prior to this, a bulge heel is provided in close contact with the rounded concave portion of the rim over the entire circumference, the rubber hardness of the bulge heel is set to 65 degrees or more in JIS hardness, and a portion adjacent to the bulge heel radially outward. In the bead core buried in the bead portion, the number of cord stacking steps in the bead portion height direction is equal to or greater than the number of parallel cords in the bead portion width direction. Those were.

Hereinafter, this will be described more specifically with reference to FIG. In the figure, 1 indicates a tire, 2 indicates a bead portion thereof, and 3 indicates a bead portion 2 of the tire 1.
2 shows a standard rim for fitting the rim. Reference numeral 4 denotes a sidewall portion of the tire, and reference numeral 5 denotes a bead core embedded in the bead portion 2. Here, the standard rim 3 is provided with an inclined bead sheet 6 inclined at an angle of, for example, 5 ° ± 1 °.
And a rounded concave portion 7 that continues outward in the width direction of the inclined bead sheet 6 and a curved flange 8 that continuously and outwardly reflexes further outward.

[0009] Soshiteko In this, the bead portion 2 is provided with a bulge heel 9 in close contact with the Sumimaru recess 7 of the rim 3. The bulging allowance d of the bulging heel 9 at the time of vulcanization molding of the tire is:
In the cross section of the rim 3 in the width direction as shown in the drawing, the straight bead sheet 6 is extended to the rounded concave side, and the curved flange 8 connected to the rounded concave portion 7 is brought into contact with the center of the rim 3. It passes through a base point Q on a bead portion planned for tire design corresponding to an intersection point P with a straight line m orthogonal to the axis, and is determined on the basis of a perpendicular line n downward from the base point Q to the tire center axis. The margin d is 2 mm or more.

In such a bead portion 2, at least a portion of the swelling heel 9 is formed of hard rubber having a JIS hardness of 65 ° or more, and a portion adjacent to the swelling heel 9 radially outward. Providing an annular depression 10 consisting of a concave curved surface,
Further, the number of cord stacking stages in the bead portion height direction of the bead core 5 embedded in the bead portion 2 is equal to or greater than the number of parallel cords in the bead portion width direction.

[0011]

In general, the tire 1 has the straight line l and the straight line m described above.
An appropriate interference is given to the bead portion 2 with respect to the rim diameter D defined by the diameter of a circle whose radius is the distance from the intersection point P to the rim center axis.

A tire 1 having such a bead portion 2
, The arrangement on the rim, for each bead part 2,
This is done by partially passing over the curved flange 8 of the standard rim 3 in a sequential manner, and the subsequent assembly of the tire 1 is carried out by filling the tire with the internal pressure until the specified internal pressure is reached. This is done by pushing the part 2 outwardly along the inclined bead sheet 6 until the outer surface of the bead part contacts the curved flange 8.

[0013] The progress of the rim assembly will be described with reference to the conventional tire-rim assembly shown in FIG.
However, as it moves outward on the inclined bead sheet, the degree of tightening and fitting increases, but the frictional resistance of the bead portion 21 that hinders this movement is not necessarily uniform over the entire circumference. A large part of the outer surface of the bead portion first comes into contact with the curved flange 24 of the rim 22, and this contact state varies depending on the circumferential position of the outer surface of the bead portion. Once such a contact state occurs, the air sealed in the gap 25 between the outer surface of the bead portion and the rim 22 generates the air in the bead portion.
21 further outward movement along the inclined bead seat will be limited by its pressure increase,
Even if the tire itself is vulcanized and formed with a sufficient uniformity due to the radial position, size, etc. of the gap 25 depending on the tire circumferential position, the wheel as a tire-rim assembly RRO increases,
As a result, the RFV increases.

On the other hand, according to the present invention, when the rim as described above is advanced, first, the swelling heel 9
Closely adheres to the rounded concave portion 7 of the rim 3, and then, under compression deformation of the bulging heel 9, the outer surface of the bead portion comes into contact with the curved flange 8. The occurrence of such a gap 25 is sufficiently prevented, and the tire 1
Is easily and highly accurately aligned with the center axis of the standard rim 3, so that the RRO of the wheel can be reduced and RFV can be effectively suppressed.

Here, the swelling allowance d of the swelling heel 9 is preferably set to a size sufficient to fill the gap 25 described above, and is preferably in the range of 2 mm to 4 mm in a normal passenger car tire.

Further, the bead portion can firmly fix the bulging heel 9 and eventually the tire 1 to the rounded corner recess 7 by making the rubber hardness of the bulging heel 9 at least 65 degrees in JIS hardness. In addition, the swelling heel 9 can advantageously lead uniformly to the corner round recess 7 over the entire circumference, but the hardness is preferably up to 80 degrees.

Incidentally, the number of cords of the bead core 5 embedded in the bead portion 2 is naturally limited in relation to the cross-sectional area of the bead core 5 and the like. By making the number of cord stacking stages in the vertical direction equal to or more than the number of parallel cords in the width direction of the bead portion, the high-pressure contact area between the outer surface of the bead portion, the rounded concave portion 7 and the curved flange 8 is sufficiently widened, This results in a further reduction of the wheel RRO and ensures continuous suppression of RFV.

[0018]

The effects on the RRO (mm) and the RFV (kgf) when the bulging amount of the bulging heel, the rubber hardness of the bulging heel, and the arrangement of the cords of the bead cords are respectively changed will be described below. . The tire type is a tubeless tire for a passenger car, the size of which is 205/65 R 15, and the applicable rim is 15 × 6JJ. As shown in FIG. 2, the code arrangement was made into five rows and five rows, and the bulging amount d of the bulging heel 9 was changed in a range of 0 mm to 4 mm. Table 1 shows the measured values of RRO and RFV at this time.

[0019]

[Table 1]

According to Table 1, it can be seen that both RRO and RFV are significantly improved by setting the swelling amount d to 2.0 mm or more.

In the above description, the tire 1
The RRO and RFV when the rubber hardness of the swelling heel 9 is changed in the range of 50 to 80 degrees with the swelling amount d of the swelling heel 9 of 2.0 mm, the bead arrangement in five rows and five rows, and As shown in FIG.

[0022]

[Table 2]

According to this, it is clear that RRO and RFV are particularly reduced at a rubber hardness of 65 degrees or more.

Further, the bulging amount d of the bulging heel 9 is set to 2.0 mm.
The RRO and RFV when the JIS hardness of the bulging heel 9 is 70 degrees and the code arrangement of the bead core 5 is changed to four rows, six rows, five rows, five rows and six rows, four rows are shown in Table 3. It became.

[0025]

[Table 3]

From Table 3, it is apparent that when the number of stages is equal to or greater than the number of columns, the effect of improving RRO and RFV is large.

[0027]

According to the present invention, a conventional rim is used without changing the shape of the rim, and no special consideration is required for the rim assembling operation. Since accurate seating is performed, the RRO of the wheel can be reduced, and RFV can be effectively suppressed. In addition, here, by setting the JIS hardness of the bulging heel to 65 degrees or more, the bulging heel can be evenly and firmly fixed to the rounded concave portion, and the bead arrangement of the bead core is specified. Accordingly, it is possible to enlarge the high-pressure contact area of the outer surface of the bead portion with the rim, further improve the RRO of the wheel, and further improve the RFV, and make it possible to suppress the RFV for a long time.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention before and after a rim is assembled.

FIG. 2 is a diagram showing an example of a code arrangement of a bead core.

FIG. 3 is a partial sectional view showing a conventional tire-rim assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tire 2 Bead part 3 Standard rim 4 Side wall part 5 Bead core 6 Inclined bead seat 7 Corner concave part 8 Curved flange 9 Swelling heel 10 Annular dent

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60C 15 / 00,15 / 02 B60C 15 / 024,15 / 04

Claims (1)

(57) [Claims] 1. A standard rim having an inclined bead sheet, a rounded concave portion successively extending outwardly in the width direction of the inclined bead sheet, and a curved flange that is bent in an outward direction. Make sure the beads are tightly fitted
Ing Te tire - a rim assembly, are in close contact with the bead portion, prior to contact with the curved flange and the bead portion outer surface opposed thereto of the rim over its entire circumference against Sumimaru recess of the rim Rise the output heel is provided, the rubber hardness of the bulging heel this <br/> not less than 65 degrees in JIS hardness, concave surface portion adjacent radially outwardly of the bulging heel
An annular recess the provided also of bead cores embedded in the bead portion, a cord stacked stages of the bead portion height direction, ing as a code in parallel the number of bead width and the same or higher tire - a rim
Assembly .