GB1563441A - Automobile wheel for tubeless tyres - Google Patents

Description

(54) AUTOMOBILE WHEEL FOR TUBELESS TIRES (71) We, BRIDGESTONE TIRE KABU- SHIKI KAISHA, a Japanese Body Corporate, of No. 1-1, 1-chome, Kyobashi, Chuo-ku, Tokyo, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to automobile wheels for tubeless tires and more particularly to a novel tubeless tire wheel construction which can permit continuous running of an automobile even if it has its tire punctured while running.

Generally speaking, it is the current practice that, in order to facilitate positioning of the tyre on the rim for a tubeless tire wheel, the center portion of the rim is recessed deeply to the wheel axis of the whole circumference providing a drop center portion.

With this rim construction, when an automobile has its tire punctured while it is running. a danger may arise in that the tire has its bead easily slipped into the rim center portion with the resultant disengagement of the time from the rim. The tire is usually made to permit continuous running without any danger if the tire bead is prevented from dropping into the rim center portion even when the tire is punctured to allow inevitably the disengagement of its bead from the bead seat of the rim.

Without such danger, therefore, the driver can drive his car, for example, to a safer place for tire replacement after leaving the running lane or to a tire repair shop. In order to enable the continuous running after puncture, one of the prior art proposals is that the recessed rim center portion is filled up with a rubber or metal band after positioning of the tire on the rim and before tire inflation. Another proposal is that the rim center portion is flattened by means of a press device after the positioning of the tire on the rim. However, the former proposal cannot be free from the disadvantage that the positioning of the tire on the rim requires additional time and labor and that the band may probably come out of place during the running time.The disadvantage concomitant with the latter proposal is that the subsequent removal of the tire from the rim becomes impossible to invite inevitable disposal of the rim itself usimultaneollelv as the tire is to be replaced, thus making the proposal uneconomical.

According to the present invention there is provided an automobile wheel for eup- porting a tubeless tire comprising a disk, a rim attached to said disk and including a pair of ring-shaped bead seats spaced from the disk on opposite sides thereof and a cylindrical base portion having a slightly smaller diameter than the bead seats and extending between said bead seats. an arcuate groove formed in said cylindrical base portion, said groove being coaxial with said base portion and extending around from 2/5 to 3/5 of the circumference thereof, said arcuate groove having an axial width ranging from 1 to 2 times that of each of said bead seats and a radial depth of at least 1/25 of the diameter of said cylindrical base portion.

The wheel of the invention can permit continuous running of the automobile even if it has its tire punctured while running and also facilitates the positioning and removal of a tire on and from the wheel in a similar manner to the conventional construction having the recessed center portion.

In order that the invention may be moru clearly understood, the following description is given by way of example only with reference to the accompanying drawings in which: Fig. 1 is an axial section of a portion of an automotive tubeless tire wheel exemplifying the present invention; Fig. 2 is a cross section taken along the line II--II of Fig. 1; Fig. 3 is a perspective view of the tubeless tire wheel as shown in Fig. 1; and Fig. 4 is similar to Fig. 3 but shows another embodiment of the present invention.

Indicated at reference numeral 10 is an automobile tubeless tire wheel which has a (not shown) tubeless tire mounted thereon.

The wheel 10 is composed generally of a disk 11 and a rim 12 which is attached to the outer circumference of the disk 11. The rim 12 is composed of a pair of ring-shaped bead seats 13 and 131, which are spaced at the both sides of the rim 12, and of a cylindrical flat base portion 14, which extends with a slightly smaller diameter than each of the bead seats 13 and 131. These bead seats 13 and 131 are made to have such opposite tapers of about 5 degrees that their diameters are progressively reduced to the axial central portion of the wheel 10. An arcuate groove 15 is formed in the vicinity and in parallel with one of the bead seats, for example, the bead seat 13. There is formed between the arcuate groove 15 and the bead seat 13 a hump portion 16 which is made to slightly protrude radially outwardly of the wheel- 10 from the surface of the flat base portion 14.The arcuate groove 15 is also made to have an axial width (W} ranging 1 to 2 times of that of each of the bead seats 13 and 131-and a radial depth (D) of at least 1/25 of the diameter of the flat base portion 14. The groove 15 thus sized is arranged to extend 2/5 to 3/5 times of the circumference of the flat base portion 14.

Fig. 3 is a perspective view showing the rim 12 which is formed with the arcuate groove 15, as has been described with reference to Figs. 1 and 2. In Fig. 4, another embodiment of the present invention is shown, in which a plurality of short balancer grooves 17 are formed in the rim 12. These balancer grooves 17 are made to have substantially the same section as that of the arcuate groove 15 and arranged at opposite positions in the circumferential extension of the arcuate groove 15. The balancer grooves 17. are provided to establish the balanced condition with the arcuate groove 15 while the rim 12 is turning. Although the shown embodiment has the balancer grooves 17 in a plural number, this number may be optional, namely, at least one in the present invention.

The numerical limitations of the size of the arcuate groove 15 will now be explained in the following.

The groove 15 is provided to be big enough for assistance in positioning the tire on the rim but it is not so big that in the event of a puncture a tire bead, or both beads, can slip into it. More particularly, the positioning of the tire on the rim becomes impossible if the axial width of the groove 15 is less than that of each of the bead seats 13 and 131, whereas the groove 15 will admit one of the beads of a tire upon deflation if its width exceeds two times of the width of the bead seats 13 and 131. The positioning of the tire on the rim also becomes impossible if the radial depth of the groove 15 is less than 1/25 of the diameter of the flat base portion 14. The upper limit of the groove depth can be enlarged as much as possible provided there occurs no hindrance when the wheel is attached to an automobile.As to the length of the groove 15, moreover, the positioning of the tire on the rim is also impossible if the extension of the groove 15 is less than 2/5 of the circumference of the flat base portion 14. If, on the other hand, the groove extension exceeds 3/5 of the circumference of the flat base portion 14, one of the beads will be allowed to drop into the arcuate groove 15 upon tire deflation.

Thus, even when the tire is deflated to invite shift of its bead from the bead seat 13 or 131 of the rim 12 to the arcuate groove 15, the leading end or toe of the bead will abut against the open edge of the groove 15 but never drops thereinto, preventing the axis of rotation of the tire from becoming eccentric to that of the rim 12. This is partly because the groove 15 is formed at a portion of the circumference of the fiat base portion 14 and partly because the wheel 10 itself is turning at a high speed. Even if, therefore, a driver has his tire punctured suddenly during his driving operation, he can continue his safe drive without any failure to manipulate the handle.

It has been found by the experiments conducted by us that the unbalance in rotation could be remedied to a practically satisfactory extent even in case the wheel of Fig. 3, namely, the wheel having no short balancer groove 17 of Fig. 4 was assembled for use with a tire. The remedy was either to position the center of gravity of the wheel unbalance at the circumferential center of the arcuate groove 15 or to attach a small balancer weight to a portion of the groove 15 after the positioning of the tire on the rim.

As the case may be, moreover, the groove 15 itself can be used as a place where such a lubricant as providing smooth shift of the buckling points upon puncture of the tire is stably reserved.

EXAMPLE A test wheel was prepared by assembling a tire of 185/70 HR14 with a rim of 5J x 14.

This rim was sized such that the arcuate groove 15 had its width (W) of 25 mm, its depth I(D) of 20 mm and its arcuate angle of extension of 150 degrees and that the bead seats 13 and 131 had their width (S) of 20 mm and their maximum spacing Q of 127 mm. The test automobile was then driven straight and curved at a speed of 40 to 100 km/hr with its tire being punctured. However, it was confirmed that the tire never left the rim nor had its bead received in the arcuate groove.

WHAT WE CL;AIM IS: 1. An automobile wheel for supporting a tubeless tire comprising a disk, a rim attached to said disk and including a pair of ring-shaped bead seats spaced from the disk on opposite sides thereof and a cylindrical base portion having a slightly smaller diameter than the bead seats and extending between said bead seats, an arcuate groove formed in said cylindrical base portion, said groove being coaxial with said base portion and extending around from 2/5 to 3/5 of the circumference thereof, said arcuate groove having an axial width ranging from 1 to 2 times that of each of said bead seats and a radial depth of at least 1/25 of the diameter of said cylindrical base portion.

2. An automobile wheel according to claim 1, wherein said arcuate groove is arranged in the vicinity of one of said bead seats.

3. An automobile wheel according to claim 1 or 2, further comprising at least one short balancer groove having substantially the same section as that of said arcuate groove and arranged at the same axial position as said arcuate groove.

4. Automobile wheel according to claim 1, 2 or 3, wherein said arcuate groove is used for containing such a lubricant as provides smooth shift of the buckling points upon puncture of the tire.

5. An auttomobile wheel substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 or Figure 4 of the accompanying drawings.

6. An automobile wheel according to any preceding claim with a tubeless tire mounted thereon.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. tire never left the rim nor had its bead received in the arcuate groove. WHAT WE CL;AIM IS:

1. An automobile wheel for supporting a tubeless tire comprising a disk, a rim attached to said disk and including a pair of ring-shaped bead seats spaced from the disk on opposite sides thereof and a cylindrical base portion having a slightly smaller diameter than the bead seats and extending between said bead seats, an arcuate groove formed in said cylindrical base portion, said groove being coaxial with said base portion and extending around from 2/5 to 3/5 of the circumference thereof, said arcuate groove having an axial width ranging from 1 to 2 times that of each of said bead seats and a radial depth of at least 1/25 of the diameter of said cylindrical base portion.

2. An automobile wheel according to claim 1, wherein said arcuate groove is arranged in the vicinity of one of said bead seats.

3. An automobile wheel according to claim 1 or 2, further comprising at least one short balancer groove having substantially the same section as that of said arcuate groove and arranged at the same axial position as said arcuate groove.

4. Automobile wheel according to claim 1, 2 or 3, wherein said arcuate groove is used for containing such a lubricant as provides smooth shift of the buckling points upon puncture of the tire.

5. An auttomobile wheel substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 or Figure 4 of the accompanying drawings.

6. An automobile wheel according to any preceding claim with a tubeless tire mounted thereon.