GB2346591A

GB2346591A - Motor vehicle wheel with inflatable tyre

Info

Publication number: GB2346591A
Application number: GB9902972A
Authority: GB
Inventors: Neil Kenneth Weatherill
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-02-11
Filing date: 1999-02-11
Publication date: 2000-08-16
Also published as: GB9902972D0

Abstract

The wheel 10, with the inflatable tyre 12, is provided with a pressure chamber 14 which in use is arranged to provide additional air or gas as required to maintain the pressure within the tyre at a determined or pre-set value. The pressure chamber 14 comprises a substantially annular chamber around some or all of the inner well 18 of the wheel 10. In use, the pressure may be topped up manually via a valve 22, or optionally in addition, supplying compressed air by means of a small electric pump 36. The pump draws air from the exterior via a vent 38 and feeds it as required into the pressure chamber via a non-return valve 40. Alternatively the pump 36 supplies air to the tyre directly, without the chamber 14.

Description

IMPROVEMENTS IN AND RELATING TO WHEELS FOR MOTOR VEHICLES This invention relates to wheels for use on motor vehicles, and more particularly to those fitted with an inflatable tyre.

Although most motorists have experienced the inconvenience of a flat tyre, it is no longer a frequent occurrence and the present invention does not seek to address such failure. As a corollary, tyres have become so reliable that few motorists now take the trouble to check the pressure in their tyres.

Under-inflation of tyres nevertheless affects performance, safety, economy and finally tyre life. The present invention seeks to provide a solution to the maintenance of the correct tyre pressure both for private cars and commercial vehicles, including lorries, coaches and off-road vehicles.

In accordance with the invention a wheel for a motor vehicle, adapted to be used with a removable, inflatable tyre is characterised in that pressure means are provided on the wheel itself, which in use are arranged to provide additional air or gas as required to maintain the pressure within the tyre at a determined or pre-set value.

In one embodiment of the invention the pressure means comprises a pressure chamber capable of receiving and retaining gas at high pressure, and a regulator communicating between the chamber and the space which in use is enclosed between the wheel and the tyre. The regulator is thus arranged in use to release the gas, normally air, as required into the said space in order to maintain the tyre at a determined operating pressure.

The invention thus offers a simple, reliable solution to the problem of maintaining the prescribed pressure in a vehicle's tyres without the need to check it on a frequent basis. The amount of gas required under normal circumstances is actually quite small, so that the pressure chamber would not normally need to be filled between services.

The chamber itself can nevertheless be relatively small and lightweight, and by making it substantially annular so that it extends around all or the majority of the wheel there need be little effect on the wheel balance or unsprung weight of the vehicle.

The regulator may either be preset or adjustable to maintain the desired pressure in the tyre. Many cars and commercial vehicles now have a sensor in each wheel to warn of pressure loss; this may act as an added precaution.

In a more sophisticated embodiment compressed air may be supplied by an electric pump which in use is arranged to pump air into the pressure chamber, or even directly into the space between the wheel and the tyre in order to maintain the determined pressure. It is also contemplated that a simple inertia pump or pair of opposed centripetal pumps could be used.

The advantage of providing a pump is that it can be arranged to restore pressure in the pressure chamber as required as it replenishes the air in the tyre resulting in the need for minimal maintenance.

The wheel is preferably provided with various sensors which provides a visual or other signals to indicate loss of pressure in the tyre or chamber.

The safety, performance and economy of a vehicle is thus significantly enhanced by fitting it with wheels in accordance with the invention due to the accurate maintenance of the optimum tyre pressure at all times.

Specific embodiments of a wheel in accordance with the invention will now be further described by way of example with reference to the accompanying drawings, in which: Figure 1 is a cross-section of a wheel with a pressure chamber in accordance with the invention; Figure 2 is a cross-section of a wheel with a pressure chamber and a pump; Figure 3 is a cross-section of a wheel with a pump arranged to discharge air directly into the tyre; and Figure 1 shows a wheel 10 for a motor vehicle, adapted to be used with a removable, inflatable tyre 12 in which a pressure chamber 14 is provided on the wheel, which in use is arranged to provide additional air or gas as required to maintain the pressure within the tyre at a determined or pre-set value.

The pressure chamber 14 comprises a welded substantially annular chamber formed by a bowed flange 16 welded around the inner well 18 of the wheel 10. The chamber 14 could equally be formed during manufacture of the wheel through stamping, spinning or casting.

A standard valve 20 is provided for normally inflating the tyre. An additional valve 22 is provided for the pressure chamber 14.

A regulator 24 provides a communicating passage between the chamber 14 and the space 26 which in use is enclosed between the wheel and the tyre.

The pressure chamber 14 is capable of receiving and retaining gas at high pressure, say 6 to 30 bar. In use the regulator 24 is arranged to release the gas, normally air, as required, into the space 26 in order to maintain the tyre at a determined operating pressure. A relief valve 28 is provided to release gas in the event of an excess pressure build-up in the tyre due to operating conditions or an eventual malfunction of the regulator 24.

The invention thus offers a simple, reliable solution to the problem of maintaining the prescribed pressure in a vehicle's tyres without the need to check it on a regular basis. The amount of gas required to maintain the pressure in the tyre under normal circumstances is actually very small, so that the pressure chamber does not normally need to be filled between vehicle services.

The chamber 14 itself can be relatively small and lightweight, and by making it substantially annular so that it extends around all or the majority of the wheel there need be is little effect on the wheel balance or unsprung weight of the vehicle.

The regulator 24 may either be preset or adjustable to maintain the desired pressure in the tyre. Many cars and commercial vehicles now have a sensor in each wheel to warn of pressure loss; this may act as an added precaution. Transducer pads 34 for these are shown by way of example.

Figure 2 shows a more sophisticated embodiment of the invention. As above, the wheel 10 has a tyre 12 and a bowed flange 16 welded around the inner well 18 of the wheel to produce the pressure chamber 14.

In this embodiment the high pressure air is normally supplied to the pressure chamber 14 from an external source through the regulator 22 as above. However, in use the pressure may be topped up by supplying compressed air by means of a small electric pump 36 fitted to the inner well 18. The pump draws air from the exterior via a vent 38 and feeds it as required into the pressure chamber via a non-return valve 40.

The pump 36 is powered either by batteries (not shown) or by an electric supply from the vehicle via a slip-ring or induction circuit. It is controlled by a pressure sensor which detects a drop in pressure in the pressure chamber 14.

In Figure 3 the arrangement of the wheel 10 and tyre 12 is similar to that shown in Figure 2. As in Figure 2 a pump 36 is shown mounted in the inner well 18 of the wheel, but operated to pump air directly into the space 26 between the wheel and the tyre in order to maintain the determined pressure via a non-return valve 40. The pump 36 is preferably driven by an electric motor controlled by a pressure sensor. It is also contemplated that a simple inertia pump could be used. This embodiment is particularly suited to being retro-fitted to the wheels of an existing vehicle.

The wheel is preferably provided with a sensor which provides a visual or other signal to indicate when the pressure in the chamber falls below a minimum operating pressure.

It is equally envisaged that the regulator or the pressure in the system could be regulated remotely, from for example within the vehicle, so that the tyre pressures could be adjusted for loading or road conditions.

In order to prevent the pressure chamber from being exhausted by a slow puncture, a flow limiter may be arranged to cause the regulator to close in the event of an abnormal loss of pressure. A manual over-ride is then provided so that the tyre can be reflated, albeit temporarily.

In all instances it is anticipated that an over-pressure valve 28 will be provided so that excessive pressure may be vented to the atmosphere in the event that an abnormality or malfunction develops with the regulator 24 or for any other reason.

Claims

CLAIMS 1. A wheel for a motor vehicle, adapted to be used with a removable, inflatable tyre characterised in that pressure means are provided on the wheel, which in use are arranged to provide additional air or gas as required to maintain the pressure within the tyre at a determined or pre-set value.
2. A wheel as claimed in claim 1 and further characterised in that the pressure means comprises a chamber capable of receiving and retaining gas at high pressure, and a regulator in a passage communicating between the chamber and the space which in use is enclosed between the wheel and the tyre, the regulator being arranged in use to release gas as required into the said space in order to maintain the tyre at a determined operating pressure.
3. A wheel as claimed in claim 2 and further characterised in that the chamber is substantially annular and extends around all or the majority of the wheel.
4. A wheel as claimed in claim 2 or 3 and further characterised in that the regulator is preset or adjustable to maintain a determined pressure in a tyre when fitted to the wheel.
5. A wheel as claimed in claim 1 and further characterised in that the pressure means comprises an electric pump which in use is arranged to pump air directly or indirectly into the space between the wheel and the tyre in order to maintain the determined pressure.
6. A wheel as claimed in claim 1 and further characterised in that the pressure means comprises a centripetal or inertia pump arranged in use to pump air directly or indirectly into the space between the wheel and the tyre in order to maintain the determined pressure.
7. A wheel as claimed in claim 5 or 6 and further characterised in that in use the pump is arranged to restore pressure in the pressure chamber by replenishing the air supplied to the space between the wheel and the tyre.
8. A wheel as claimed in any preceding claim and further characterised in that the pressure chamber is provided with a sensor which is arranged to provide a visual or other signal to indicate the gas pressure in the chamber is below a minimum design pressure.
9. A wheel as claimed in any preceding claim and further characterised in that a flow limiter is arranged to cause the regulator to close in the event of an excessively rapid loss of pressure.
10. A wheel as claimed in claim 9 and further characterised in that manual means is provided to override the flow limiter so that the tyre can be temporarily reflated.
11. A wheel as claimed in any preceding claim and substantially as hereinbefore described with reference to any one of the accompanying drawings.