GB1587902A

GB1587902A - Tyre and wheel assemblies

Info

Publication number: GB1587902A
Application number: GB3967176A
Authority: GB
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1976-09-24
Filing date: 1976-09-24
Publication date: 1981-04-15
Also published as: GR63571B; IT1087462B; FR2365449A1; DE7729445U1; BR7706319A

Description

(54) IMPROVEMENTS TO TYRE AND WHEEL ASSEMBLIES (71) We, DUNLOP LIMITED, a British Company of Dunlop House, Ryder Street, St. James's, London S.W.1, 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: This invention relates to tyre and wheel assemblies and in particular to tubeless pneumatic tyre and wheel assemblies.

In a conventional tubeless pneumatic tyre and wheel assembly in which the tyre is mounted on a well base rim, loss of air leaves the assembly in a dangerous condition as any substantial side force applied, due to steering of the vehicle, causes the tyre to be displaced from the bead seats into the well of the rim. This is followed by the tyre becoming detached from the rim by means of the beads entering the well at one side allowing the diametrically opposed beads to pass over the rim flanges.

As used hereinafter in the description and claims the terms outboard and inboard bead seats refer to the bead seats which are on the outside and inside respectively when the assembly is mounted on a vehicle.

Previous attempts to provide safety tubeless pneumatic tyre and wheel assemblies have been well-less rims, well-filler devices, means for locking the outboard tyre bead into place on its bead seat, or means for locking both tyre beads onto their respective bead seats.

The present invention depends on the realisation that for a tubeless pneumatic tyre and wheel assembly in which the tyre is mounted on a well-base rim, if the inboard bead is retained on its bead seat, the other bead need not be so retained.

According to the present invention a tubeless pneumatic tyre and wheel assembly comprises a tyre having a pair of axially spaced-apart beads, a rim having a well and a pair of axially spaced-apart bead seats, one either side of said well, and a single circumferentially extending hump on the rim, said hump being adjacent to the inboard bead seat and acting to prevent dislodgement of the inboard bead towards the well.

Thus in use on a vehicle when the assembly is the outer wheel in a turn the outboard bead may enter the well and may sometimes move onto the inboard bead seat so as to contact the inboard tyre bead which is against its bead seat and flange. The outboard bead is, however, unable to leave the wheel even when in the well due to the inboard bead being retained, the tyre carcass limiting the bead separation and the applied force direction being inboard of the vehicle. When the same assembly becomes an inner wheel, i.e. on the opposite turning lock, the forces applied to the tyre and wheel assembly are very much less than the forces applied to the outer wheel and the hump prevents movement of the inboard bead into the well. The result is an assembly in which the tyre does not leave the rim which provides improved safety over conventional tyre and well-based wheel assemblies.

The hump may be provided in combination with a substantially flat ledge region outboard of the hump at the inboard side of the wheel rim.

Preferably the tyre is a radial ply tyre having a steel or textile radial ply carcass and a steel or textile breaker assembly; furthermore, the tyre preferably has a 'low aspect ratio for instance, having an aspect ratio of 30 - 75% and more preferably in the range of 55 -65%.

Further aspects of the present invention will be apparent from the following description of an embodiment of a tubeless pneumatic tyre and wheel assembly in accordance with the present invention given by way of example only.

The tyre is a radial ply tubeless tyre having an aspect ratio of 65%, a pair of axially spaced-apart beads and a breaker reinforcemenl The wheel rim comprises two bead seats which are the outboard and inboard bead seats respectively of the assembly separated by a well and terminating at their axially outer edges in respective bead retaining flanges.

Axially outboard of the inboard bead seat is formed on the rim a circumferentially extending hump.

The hump provides means of restraining the inboard bead at its seat when side force is applied to the tyre when the assembly is used on a vehicle with the tyre in a substantially deflated condition.

It has been shown that the retention of the inboard bead only is sufficient to provide a safe assembly and in the case of a vehicle manoeuvre applying an inwardly directed side force the outboard bead may be displaced into the well but reasonable degree of side force can still be transmitted by the tyre and wheel assembly and the tyre does not leave the wheel rim. When an outwardly directed side force is applied the tyre and wheel assembly is on the inside of the vehicle and less side force is applied to the tyre. The simple bead lock of the bead engaging the hump is then sufficeint to retain the bead at its seat and once again the tyre is in a safe condition even through deflated.

WHAT WE CLAIM IS: 1. A tubeless pneumatic tyre and wheel assembly comprising a tyre having a pair of axially spaced-apart beads, a rim having a pair of axially spaced-apart bead seats, one either side of said well, and a single circumferentially extending hump on the rim, said hump being adjacent to the inboard bead seat and acting to prevent dislodgement of the inboard bead towards the well.

2. An assembly according to Claim 1 wherein the wheel rim immediately outboard of the hump is straight in cross-section so as to provide a substantially flat ledge region outboard of the hump at the inboard side of the wheel rim.

3. An assembly according to Claim 1 or Claim 2 wherein the tyre is a radial ply tyre having a steel or textile radial ply carcass and a steel or textile breaker assembly.

4. An assembly according to any one of Claims 1 to 3 wherein the tyre has an aspect ratio of between 30 and 75%.

5. An assembly according to Claim 4 wherein the tyre has an aspect ratio in the range of 55 - 65%.

6. A tubeless pneumatic tyre and wheel assembly as claimed in Claim 1 substantially as hereinbefore described.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. on a vehicle with the tyre in a substantially deflated condition. It has been shown that the retention of the inboard bead only is sufficient to provide a safe assembly and in the case of a vehicle manoeuvre applying an inwardly directed side force the outboard bead may be displaced into the well but reasonable degree of side force can still be transmitted by the tyre and wheel assembly and the tyre does not leave the wheel rim. When an outwardly directed side force is applied the tyre and wheel assembly is on the inside of the vehicle and less side force is applied to the tyre. The simple bead lock of the bead engaging the hump is then sufficeint to retain the bead at its seat and once again the tyre is in a safe condition even through deflated. WHAT WE CLAIM IS:

1. A tubeless pneumatic tyre and wheel assembly comprising a tyre having a pair of axially spaced-apart beads, a rim having a pair of axially spaced-apart bead seats, one either side of said well, and a single circumferentially extending hump on the rim, said hump being adjacent to the inboard bead seat and acting to prevent dislodgement of the inboard bead towards the well.