Patent ID: 12194793

Referring now toFIGS.1to3, there is shown a tyre T according to an embodiment of the invention. The tyre T comprises first and second side walls1,2with a contact wall3extending therebetween. The first and second side walls1,2and contact wall3comprise a carcass C of plys of elastomeric material with a liner L extending across the inner surface of the walls to seal the tyre T. The tyre T is shown fitted to a wheel rim WR inFIG.1.

The contact wall3comprises a tread band30on its external surface, comprising first, second and central tread portions30a,30b,30c, in this embodiment. The tread portions30a,30b,30care selected to provide a relatively increased coefficient of friction, in this embodiment. In this embodiment, the first and second tread portions30a,30bare formed from a compound of material having a relatively lower wear resistance and a relatively higher coefficient of friction than is the compound of material from which the central tread portion30cis formed. In embodiments, however, the tread portions30a,30b,30cmay be made from the same compound of material.

Plural chambers4,5,6are defined within the tyre T. A main chamber4extends from the first side wall1to the second side wall2and comprises a majority of the internal volume of the tyre T, in this embodiment. Side chambers5are located on either side of the tyre T (e.g. adjacent the side walls1,2). Central chambers6are located between the side chambers5and adjacent the contact wall3.

The side chambers5and central chambers6may be formed by any suitable means. In some embodiment, the chambers5,6may be formed separately and then bonded to an inner surface of the carcass of the tyre T. Although two side chambers5and three central chambers6are shown there may be any suitable number of these chambers5,6as will be appreciated by one skilled in the art. In embodiments, the tyre T may be absent side chambers5and/or be absent central chambers6.

The tyre T further comprises a heater7, which comprises a heating element70in this embodiment. The heating element70is embedded within the contact wall and comprises belting of the tyre T which also provides structural rigidity to the tyre T. The heating element70is operatively attached to a source of electrical energy (not shown), in this embodiment.

An insulation means comprising an insulation layer8is disposed within the contact wall3and is arranged to protect the contact wall3from heating by the heating element70, in use, in this embodiment. For example, the insulation layer8may be arranged to protect the contact wall3from delamination due to heating. The insulation layer8may be formed of any suitable insulation material, for example a polymer or fabric having insulation properties. The insulation layer8extends across the width of the contact wall, from the first to the second side wall, in this embodiment. The insulation layer8is arranged to mitigate transmission of heat from the heater7to or toward the tread band30of the contact wall, in this embodiment.

A temperature sensor9is arranged to measure the temperature of the contact wall3, in this embodiment. The temperature sensor9is shown embedded in the contact wall3of the tyre T, however this need not be the case and, instead the temperature sensor9may be located at any suitable location to directly measure the temperature of the contact wall3. In embodiments, there may be plural temperature sensors, for example which may be arranged to measure the temperature of different parts of the tyre T (for example different walls1,2,3thereof). In embodiments, the temperature sensor9may be arranged to measure the temperature of the first and/or second side wall, in addition to or alternatively to the contact wall3. The temperature sensor9is a thermocouple in this embodiment.

Air pressure within the chambers4,5,6is altered, in use, by a pumping system40comprising a pump40which may comprise any suitable pump, for example a piston pump. The pump40is located outside of the tyre T in this embodiment. In embodiments, however, the pump40may be located inside of the tyre T.

The present embodiment comprises a control unit20, inside or outside of the tyre T, which is configured to control the pressure of fluid within the chambers4,5,6. A valving system42in the tyre T selectively allows and prevents the flow of fluid into and/or out of the chambers4,5,6thereby allowing inflation and deflation thereof. The control unit20is operably connected to the pump40of the pumping system40and the valving system42.

The tyre T may comprise a manifold41or other fluid communication assembly arranged to direct fluid flow into and/or out of the chambers5,6(and optionally main chamber4) and to/from the pump40. The tyre T may comprise a source of fluid (not shown) which may be arranged to supply fluid to and/or receive fluid from the chambers4,5,6. Such a source of fluid may be external or internal to the tyre T and may comprise a pressurised container, for example.

The internal volumes of chambers5,6may be configured and/or selected such that fluid can be transferred from one chamber5to one or more of the other chambers5,6, in use, to inflate said one or more of the other chambers5,6without needing to access fluid from the main chamber4or a source of fluid (not shown). Alternatively or additionally, fluid may be taken from the main chamber4and redistributed to one or more of the chambers5,6(or vice versa). By utilising adaptable valves (e.g. three way valves) the air flow network between chambers4,5,6can be simplified. Pressure transfer from and/or to the main chamber4can be used as an additional fluid supply, for example under rapid pressure change requirements.

The tyre T may comprise a sensor for sensing a rolling condition of the tyre. The rolling condition may, for example, comprise the inclination or declination of a surface over which the tyre is rolling or may roll (e.g. is about to roll). The sensor may comprise an accelerometer and/or image sensing means such as one or more cameras. The control unit20may receive rolling condition data from the sensor (e.g. the inclination or declination of a surface over which the tyre is rolling) and may operate the pump40to alter the pressure in one or more of the chambers4,5,6.

In use, the temperature sensor9measures the temperature of the contact wall3and transmits this information to the control unit20. If the temperature of the contact wall3is below a threshold temperature (e.g. a pre-set threshold temperature) the control unit20operates the heater7to heat the contact wall3. Electrical energy is supplied via an electrical connection to the heating elements70of the heater, which resistively generate heat. The heated heating elements70transfer thermal energy to the contact wall3via conduction and radiation. Provision of the insulation layer8advantageously reduces heat losses from the contact wall3to the ambient surrounds of the tyre T (for example into a surface against which the tyre T is rolling). The quantity of thermal energy required is thereby relatively reduced and, beneficially, heating of the contact wall3to or toward a desired temperature (e.g. the threshold temperature) is therefore relatively more rapid and requires a relatively reduced quantity of electrical energy to be maintained. The heater may consume about 1 kW of electrical power. Additionally, the insulation layer8may beneficially improve thermal distribution through the contact wall3of the tyre T by aiding retention of thermal energy therewithin. Furthermore, provision of the insulation layer9may mitigate the transmission of heat from the heater7to the tread band30, thereby helping to maintain its rigidity and hence its grip against a rolling surface. Yet further, the insulation layer8may reduce incidence of delamination of the tyre T by relatively reducing (with respect to a tyre T absent such an insulation layer8) the flow of thermal energy through the layers of the tyre T.

When the measured temperature of the contact wall3is less than or equal to the threshold temperature the control unit20operates the heater7to stop heating the contact wall3. Advantageously, heating the contact wall3(and/or the first side wall1and/or second side wall2) relatively reduces the pressure change required in the chambers5,6to generate a given amount of deformation of the external shape of the tyre T. Accordingly, a relatively less powerful pump40may be used and/or less energy may be required to operate the pump40. Additionally, we have found that the tyre T is more reactive to changes of pressure in the chambers5,6during ‘cold’ conditions, for example where the ambient temperature is relatively cold (e.g. below 10 degrees centigrade) or where the tyre T has not rolled over a surface for an extended period of time such as when a vehicle to which the tyre is attached has been stationary for an extended period of time (e.g. parked over-night).

In embodiments, the control unit20may be configured to operate the tyre T according to different operating modes. For example, the control unit20may be configured to switch the tyre T between different operating modes, such as an economy mode, a performance mode and an off-road mode.

In an economy mode the main chamber4may have a relatively high pressure and the side and/or central chambers5,6may have a relatively lower pressure, thereby promoting contact of the central portion30cof the tread band30with a surface over which the tyre T is rolling, whilst minimising contact of the first and second portions30a,30bof the tread band30with said surface. Advantageously, the lower wear resistance material of the first and second portions30a,30bof the tread band30may be at least partially protected from wear against the surface over which the tyre is rolling. Additionally, the rolling resistance of the tyre T against the surface may be relatively reduced due to reduced contact with the material of the first and second portions30a,30bwhich has a relatively higher coefficient of friction. Accordingly, operating costs (e.g. energy costs) of the vehicle may be relatively reduced in this mode.

In a performance mode the side chamber5(and optionally one or more of the central chambers6) may have a relatively higher pressure (than in economy mode). In embodiments, the main chamber4may have a relatively reduced pressure. The external shape of the tyre T may be altered by this pressure distribution to relatively increase contact of the first and second portions30a,30bof the tread band30with a surface over which the tyre T is rolling. Advantageously, additional grip and stiffness of the tyre T with the surface may be provided by this arrangement, due to the relatively higher coefficient of friction of the material from which the first and second portions30a,30bof the tread band30are formed. Such a mode may be particularly advantageous during cornering, heavy breaking, acceleration and the like, where the tyre T may be subjected to relatively high forces from friction against the surface over which it is rolling. As will be appreciated, the pressure in the chambers4,5,6may be altered such that a greater proportion of the first portion30aof the tread band30is in contact with the surface over which the tyre T is rolling than is the second portion30bof the tread band30, or vice versa (for example for cornering).

In an off-road mode the central chambers6(and optionally the side chambers5) may have a relatively low pressure (e.g. lower than in economy and performance modes) whilst the main chamber4may have a relatively high pressure (with respect to the central chambers6and side chambers6). In this way the contact wall3may more readily deform upon contacting bumps and/or objects on the surface over which the tyre T is rolling. Beneficially, this may reduce the effect of the unevenness of the surface and hence enhance the comfort of occupants of a vehicle to which the tyre T is attached. Additionally, the grip of the tyre T with the uneven surface may be relatively enhanced by such a pressure distribution within the chambers4,5,6.

Referring now toFIG.4, there is shown a tyre1T according to a further embodiment of the invention, wherein like features to those described in respect of the tyre T shown inFIGS.1and2are denoted by like references preceded by a ‘1’ and will not be described herein further. The tyre1T shown inFIG.3differs from that shown inFIGS.1and2in that only two central chambers16are provided.

It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. For example, although the heater7is shown as comprising a heating element70comprising belting of the Tyre this need not be the case and, instead, the heating element70may be in addition to or provided instead of the belting. Alternatively, the heater7may comprise an alternative means for heating the first side wall1, second side wall2and/or contact wall3. For example, in embodiments, the heater7may comprise conduits through which a heated medium (e.g. a heated fluid) is passed to exchange heat with the first side wall1, second side wall2and/or contact wall3.

Additionally or alternatively, in embodiments the tyre T,1T may be provided absent the chambers5,6,15,16.

Additionally or alternatively, in embodiments, the tyre T,1T may not include the insulation layer8. Additionally or alternatively, although the insulation means comprises an insulation layer8is described as being arranged to mitigate transmission of heat from the heater7to the tread band30and extending across the width of the contact wall3from the first side wall1to the second side wall2this need not be the case and, instead, the insulation layer8(or other suitable insulation means) may extend across only a portion of the width of the contact wall3between the first and second side walls1,2and/or may be arranged to mitigate transmission of heat from the heater7to only the central portion30cof the tread band30or only the first and/or second portion30a,30bof the tread band30.

Additionally or alternatively, in embodiments, the tyre T,1T may not include a tread band30.

Additionally or alternatively, although the temperature sensor9is described as being a thermocouple this need not be the case and, instead, the temperature sensor9may comprise any suitable type of temperature sensor such as a resistive temperature device (e.g. a thermistor), an infrared radiator, a bimetallic device, a liquid expansion device and the like. Additionally or alternatively, although the temperature sensor9is described as directly measuring the temperature of the contact wall3this need not be the case and, instead, the temperature sensor9may indirectly measure the temperature of the contact wall3, for example by measuring the temperature of the heating element70and/or of a component adjacent the contact wall3. In some embodiments, the temperature sensor72may be configured to determine the resistance of the heating element, from which the resistivity of the heating element can be calculated (by knowing the length and cross-sectional area thereof). The temperature of the heating element70can be calculated from the calculated resistivity or from a look-up table of temperature against resistivity performance of the heating element previously determined.

It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.