JPS58145508A - Tire-rim assembly for motorcycle - Google Patents

Abstract

PURPOSE:To prevent a tire from going off a rim during movement under puncture, by providing protruded edges on the beads of the tire which comprises a toroidal carcass and reinforcing layers of steel cords and by fitting the protruded edges in the grooves of the inner portions of the bead seats of the rim. CONSTITUTION:Fitting grooves 14 are provided on the inner portions 13 of bead seats 11 continuous to the recess 10 of a rim 9, so that the grooves extend in the circumferential direction of the rim. A tire 1 comprises beads cores 3, a toroidal carcass 4 of organic fiber cords, a tread 5 and reinforcing layers 6 of steel cords inclined at an angle of 20 to 60 deg.C to the horizontal center line of the cross section of the tire. The beads of the tire 1 are provided with protruded edges 7. After the beads are put in the recess 10 of the rim 9, the tire 1 is filled with air, so that the beads are pushed toward the bead seats 11 and the flanges 12 of the rim and the protruded edges 7 are fitted in the grooves 14. As a result, the tire 1 is prevented from going off the rim 9 during movement under puncture.

Description

[Detailed description of the invention] Even if the IQ decreases, the rigidity of the tire itself supports the vehicle load, prevents the bead of the tire from coming loose from the rim, and allows the vehicle to be safely returned to a repair shop without significant speed control. This invention relates to a tire and rim assembly for a drivable motorcycle.

In conventional tire and rim assemblies, the tire bead is held on the bead seat of the rim by compressing the bottom and outer surface of the bead using air pressure inside the tire, thereby compressing the bead between the bead seat and the rim flange. However, if the internal pressure suddenly drops due to a puncture or tire tire, the lateral force from steering wheel operation to avoid an accident will also be applied, causing the tire bead to deteriorate. The part will come off the bead seat, significantly compromising safety. Particularly in the case of motorcycle tires, when cornering, the wheel tilts significantly, and camper thrust acts in a direction to alleviate the tilt.

A suppressing force is applied to the bead portion inward of the rim seat, making it particularly easy for the two to come apart from each other.

Japanese Patent Laid-Open No. 56-2804 has proposed a tire rim assembly for safe driving by preventing the rim from coming off in the event of a puncture. This is especially intended for use in four-wheeled vehicles, as the wheels are held almost perpendicular to the road surface even when cornering. As mentioned above, no consideration is given to the case where the wheels tilt significantly. Therefore, when an assembly based on this prior art is applied to a motorcycle tire, the wheel tilts during cornering, as shown in FIG. 1, and touches the ground near the upper end of the sidewall.

Due to the flexibility of the tire bead area), the tire bead area is pushed axially inward, making it easy for the rim to come off. Therefore, is the above-mentioned prior art sufficiently effective for special motorcycle tire tires? As a result of intensive research on the structure of the tire outer skin based on the shape of the rim of the prior art, the inventor found that the problem of the rim coming off could be solved by arranging a specific reinforcing layer on the side of the tire. It turned out to be scaly. The present invention is based on such research and provides a motorcycle tire and rim assembly that enables safe driving even when a sudden drop in internal pressure occurs in the event of a puncture.

The present invention comprises a pair of left and right bead cores, a toroidal carcass extending from one bead part to the other bead part and having both ends folded back and fixed to the bead core, a tread part disposed outside the crown part of the carcass, and the carcass. A reinforcing layer made of steel cord extends from one bead part to the other on the radially outer side of the carcass ply, and a tire outer skin with a protruding toe part at the bottom of the bead.The tire is attached to the rim well. and a rim provided with a fitting groove extending in the circumferential direction adjacent to the axially inner end of at least one bead seat, and the protruding toe portion is attached to the rim so as to engage with the fitting groove. This is an assembly of motorcycle tires and rims.

Further, the present invention provides a pair of left and right bead cores, a toroidal carcass which extends from one bead portion to the other bead portion, and whose both ends are folded back and fixed to the bead core, and one of the toroidal carcass is fixed to the outside of the carcass in the radial direction or between the braais of the carcass. A reinforcing layer made of steel cord extends from one bead part to the other bead part, a rubber reinforcing layer extending from the bead part to near a part of the sill and disposed adjacent to the carcass, and a protrusion on the bottom of the bead. The tire outer skin having the toe portion is mounted on a rim having a fitting groove extending in the circumferential direction adjacent to the axially inner end of the rim well and at least one of the bead seats. This is an assembly of a motorcycle tire and rim that is mounted so as to be engaged with a fitting groove.

The present invention will be described in detail below with reference to the drawings. FIG. 2 shows a cross-sectional view of the tire and rim assembly of the present invention.

The tire outer skin (1) used in the present invention includes a pair of left and right bead cores (3) and a toroidal carcass (4) extending from one bead part to the other bead part and fixed by folding both ends (4a) back to the said bead cores. ), a tread part (5) disposed outside the crown part of the carcass, and a reinforcement N made of a steel cord extending from one bead part to the other bead part radially outside the carcass (4).
The carcass (4) is made of organic fiber cord, such as nylon.

A so-called cross ply is formed by arranging at least two layers of ply in which cords of polyethylene terrectate, rayon, aromatic polyamide, etc. are stretched four times in parallel so that the cords intersect with each other.

1. The fiber cord described in Item 11 is usually set at an angle of 20° to 70° with respect to the tire neck surface e. Here, the thickness of the carcass is preferably four or more layers from the viewpoint of maintaining the rigidity of the tire.

Next, the steel cord constituting the reinforcement RA [61
It is arranged so as to be inclined within a range of -40°. The stiffness of the tire, especially the lateral stiffness, is improved by the arrangement of the reinforcing layer (6), and this effect is particularly excellent within the above angle range. Both ends of the reinforcing layer (6) extend at bead portions f, where the bead portion refers to a region extending from the vicinity adjacent to the upper end of the rim flange to the bottom of the bead, and this region is defined by bending when the tire is running. The deformation is relatively small, and the accompanying stress concentration at the ends of the reinforcing layer is small, thus preventing the rubber from peeling off at the ends. Note that the reinforcing layer (6) can also be arranged between the plies of the carcass, in which case the reinforcing layer (6) of highly rigid steel cord is wrapped with a layer of less rigid and stretchable organic fiber cord. Therefore, the reinforcement layer (6) effectively relieves stress concentration and disperses it.
It has the advantage that it is difficult to peel off the rubber from the surface and to damage the tire.

The protruding tow portion (7) extends longitudinally from the bead core (3) in the radial direction and inwardly in the forward direction, and has a certain flexibility in the perpendicular direction with respect to the length direction. It facilitates mating with the rim, while being rigid in the longitudinal direction, so that when an axially inward force exerted on the tread portion is transmitted to the pedestal portion, the tread portion is stiffened radially and axially. An outward stress is generated in the bead core (3) and the protruding toe (7), thereby making the fit between the bead and the rim even stronger. Therefore, it is particularly preferable to use an elanuttomer material having a JISA hardness of 60-90 degrees, as shown in FIG. It is reinforced with a fiber layer (8) running from the inside to the outside.

The protruding tow portion (7) may be made of a single elastomer material as shown in Figure 2, or may be made of an annular core made of hard rubber/plastic or a bundle of fibers, which is harder than the surrounding elastomer material, as shown in Figure 3e. 1 is also good,
In this case, the fit with the rim becomes even stronger.

Next, the rim (9) used in the present invention has a rim (9) recessed in the center of the rim as shown in FIG.
) and a pair of bead seats (
ii), further comprising rim flanges (12) arranged axially and radially outwardly at both ends of said bead seat (11), said bead seat (11) having an axially inner end ( A fitting groove (14) extending one circumferential direction adjacent to 13)
It is equipped with The bead seat forms a smooth continuous downward slope from the axially outer side to the bottom of the fitting groove, and forms a steep upward slope from the fitting groove bottom to the axially inner end of the bead seat. Here, since the protruding toe portion (7) is fitted with the bottom part of the fitting groove so that the two pieces come into contact with each other, the length of the bead part (WB) is from the center of the fitting groove to the outer end of the bead seat. The distance should approximately match.

The tire outer skin can be attached to the rim in the same way as a normal tire and rim. For example, in Figure 2, after the bead part is inserted into the rim urchin /I/(1(]) over the rim flange, the air pulp (15)
By filling air from the inside, the bead is pressed toward the bead seat (11) and the rim flange (12) by internal pressure. Strongly held.

In the present invention, it is preferable to add a rubber reinforcing layer (16) to the tire outer skin adjacent to the carcass (4) and in the vicinity of a portion of the tire from the bead as shown in FIG.

The rubber reinforcing layer (16) is a relatively hard rubber with a JISA hardness of 60° to 80° and is placed between the plies of the carcass or on the outside of the carcass to reinforce the tire side part and especially prevent the tire from going flat and causing a drop in internal pressure. At the same time, the steel cord reinforcement 1m F61 prevents buckling of the sidewall part and prevents the bead part from coming off the rim. A protruding toe is provided on the leather bead I, and a steel cord reinforcement layer or a rubber reinforcement layer is provided to further strengthen the fit between the two, further increasing the size of the wheel when the internal pressure decreases. IL that comes off the rim even when tilted? A high level of safety is maintained as there is no need for

Example 1 As an example of the present invention, the tire size is 4.00 H18, the nylon cord is 4 ropes, and the cord angle is 30 degrees with respect to the circumferential direction. The outer skin of a ply tire with a reinforcing layer of steel cord is shaped as shown in Fig. 4 and size 2.
I installed it on a 15X1 B rim. As a comparative example, a rim with the steel cord reinforcing layer removed was mounted on the same rim as above.

The above tire and rim assembly is C! Used for the rear wheels of B750F-I vehicles and size 3.25H for 911 wheels.
Braking test using tires with an internal pressure of 20 kQ/d at 19,
I did a rotation test.

(b) Braking test The comparative example required a braking distance of approximately 73 m to stop while traveling at a speed of 90 h/h, whereas the braking distance in the example of the present invention was approximately 60 m, improving braking performance. did.

Offshore) Turning test radius of 20m at a speed of 19.5 & a/h (lateral G is 015)
In the comparative example, the rim did not come off at all when turning.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the tire when the vehicle is turning, Fig. 2 is a sectional view of the tire and rim assembly of the present invention, Fig. 3 is a sectional view of the bead, Fig. 4 is a sectional view of the rim, and Fig. 5 is a sectional view of the tire and rim assembly of the present invention. The figure shows a cross-sectional view of another embodiment of the tire and rim assembly of the invention. Patent Applicant Sumitomo Rubber Industries Co., Ltd. Agent Patent Attorney Yoshihei Nakamura 3 Figure 1

Claims (1)

[Scope of Claims] (1) A pair of left and right peed cores, a toroidal carcass extending from one bead part to the other bead part and fixed by folding both ends to the bead core, and a toroidal carcass disposed outside the crown part of the carcass. A tire comprising a reinforcing layer made of a steel cord extending from one bead part to the other bead part between the trend part and the radially outer side of the carcass or the braai of the carcass, and a protruding toe part at the bottom of the bead. The outer skin is attached to a rim having a circumferentially extending fitting groove adjacent to an axially inner end of a rim well and at least one bead seat, and the protruding toe portion engages with the fitting groove. An assembly of motorcycle tires and rims. (2) The assembly according to claim 1, wherein the carcass is made of Cronu ply. (5) The steel cord of the reinforcing layer is arranged at an angle of 20° to 60° with respect to the tire circumferential direction.
Assembly as described in section. (4) The assembly according to claim 1, wherein the protruding toe portion is made of an elastomer material having a J Engineering SA hardness of 60-90°. (5) The assembly according to any one of claims 1 to 5, wherein the protruding toe portion is reinforced with a fiber layer along the outer ring 3P line of the protruding toe portion from the inside to the outside of the bead portion. (6) The assembly according to claim 1, wherein the bead seat of the rim forms a smooth continuous downward slope from the axially outer side to the bottom of the fitting groove. (7) A pair of left and right ped cores, a toroidal carcass that extends from one bead portion to the other bead portion and is fixed by folding both ends to the ped core, a tread portion disposed outside the crown portion of the carcass, and the A reinforcing layer consisting of a steel cord extends from one bead part to the other bead part from the radially outer notch of the carcass to the braai of the canu, and a reinforcing layer consisting of a steel cord extends from the bead part to the vicinity of the shoulder J part and is adjacent to the carcass. The tire is attached to a tire outer skin with a rubber reinforcing layer disposed at the bottom of the bead and a protruding toe at the bottom of the bead. A motorcycle tire and rim assembly comprising a rim having a groove so that the protruding toe portion engages with the fitting groove.