WO2003068535A1

WO2003068535A1 - Tire rim

Info

Publication number: WO2003068535A1
Application number: PCT/IT2002/000094
Authority: WO
Inventors: Tonino Pisu
Original assignee: Tonino Pisu
Priority date: 2002-02-18
Filing date: 2002-02-18
Publication date: 2003-08-21
Also published as: AU2002237518A1

Abstract

Tire rim (31), comprising a hub (32) for the fastening to the motor vehicle drive, a duct (33) apt to house a tire (34) to be inflated and a plurality of connecting members between said hub and said duct; some of the connecting members (35) are hollow, so as to define a region apt to contain an aeriform, and comprise means for the inletting and/or the outletting of said aeriform from said region.

Description

TIRE RIM DESCRIPTION The present invention refers to a tire rim, the use thereof enable to eliminate, or anyhow drastically reduce, several drawbacks related to the use of air- inflated or other aeriform-inflated tires.

To date, virtually all the motor vehicles are provided with wheels consisting of a metal rim onto which a rubber tire, inflated to a pressure higher than the atmospheric one, is mounted.

The tire pressure is well-known to be one of the parameters crucially influencing a proper motor vehicle operation, e.g. in terms of roadholding, consumption, performances, etc. The suggested tire pressure value is estimated according to the specific features of the tire used, the vehicle type onto which the latter is mounted and the use to which the same vehicle is destined. In fact, instances of a production model vehicle, of a type commonly used by all, or a racing car, e.g. a Formula 1 car, designed and manufactured to run on a racetrack under certain conditions and for a certain number of laps, require different values.

However, it is crucial that the tire inflation pressure stays as constant as it is possible during the use of the vehicle, in order to ensure anyhow a homogeneous behavior over time.

Of course, this need is actually amplified and all the more felt in the field of car racing, where, especially due to the remarkable tire temperature variations, the tire pressure undergoes significant gradients, hence causing different car behaviors during the same race, thereby not enabling to attain the maximum performance levels. To date, this problem has partially been overcome with the use of specific aeriform mixtures for tire inflation. To this end, in fact, special mixtures are used which are little-influenced by temperature variations, thereby reducing the volume variations and therefore the pressure gradients inside of the tires.

However, the use of these mixtures, besides being uneconomical, does not completely overcome the problem as the mixtures used are not totally immune from this drawback .

Moreover, unavoidably, due to a defective seal between the tire and the rim, caused e.g., by flaws or strains thereof, the tire pressure tends to progressively decrease over time.

Object of the present invention is to solve the abovementioned problems of the known art, providing a tire rim comprising a hub for the fastening to the motor vehicle drive, a duct apt to house a tire to be inflated and a plurality of connecting members between said hub and said duct, characterized in that one or more connecting members of said plurality of connecting members is hollow and such as to define an inner region apt to contain an aeriform, said one or more connecting members further comprising means for the inletting and/or the outletting of said aeriform from said inner region, apt to open the latter on the inside of the tire mounted onto the rim. A first advantage entailed in the use of the rims according to the present invention lies in that those enable to keep the inside pressure of the tires nearly constant over lengthy periods of time, regardless of the variations in temperature during use. A second advantage lies in that rims according to the present invention can also be used to counter the force of gravity acting onto the vehicle, thereby lightening the latter, with the entailed chance of attaining higher performances and lesser consumption. Further advantages, features and modes of employ of the present invention will be made apparent in the following detailed description of preferred embodiments thereof, given as a non-limiting example, making reference to the figures of the attached drawings, wherein: figure 1 is a partially exploded perspective view of a first embodiment of a rim according to the present invention; figure 2 is a partially exploded side view of the rim of figure 1; figure 3 is a sectional view of one of the connecting members of the rim of figure 1, taken along line A-A; figure 4 is a partially exploded perspective view of a second embodiment of a rim according to the present invention; figure 5 is a partially exploded side view of the rim of figure 4; and figure 6 is a sectional view of one of the connecting members of the rim of figure 4, taken along line B-B. A first embodiment of a rim according to the present invention is depicted in figures 1 to 3, hereinafter reference being made thereto.

A rim 1 comprises a hub 2 apt to the mounting of the rim onto the drive gears of a vehicle and a duct 3 apt to house a tire 4, in particular a tubeless-type tire.

As it is known, likewise tires have a shape apt to implement an optimum seal onto the outside edges of the duct 3, thereby enabling, via a valve 10, the inletting of air or other aeriform inside of the region defined by the tire 4 and the duct 3.

The rim 1 further comprises three connecting members 5 having a structural function of connecting the hub 2 and the duct 3 therebetween.

The rim 1, meant as the assembly of hub, duct and connecting members, is preferably piece-formed, by steps of molding or of melting of metallic material, e.g. a light-weight alloy. Each of the connecting members 5 is hollow and such as to define an inner region 15 apt to contain air or a different aeriform or aeriform mixture.

Hereinafter, for simplicity's sake reference will still be made to an aeriform, any other aeriform mixture to be construed as comprised therein.

Each connecting member 5 comprises a valve 20 for the inletting of the aeriform, e.g., of the same type commonly used for tire inflation. The valve 20 is preferably located on a side wall of the member 5, so as to be accessible also when the tire 4 is mounted onto the rim.

Moreover, means for the inletting and/or the outletting of the aeriform from the region 15, in particular two further valves 21 and 22, open the inside region 15 on the outside, at the central section of the duct 3.

Therefore, the location of the valves 21 and 22 is such as to enable the passing of aeriform between the region 15 and the region defined by the rim and the tire itself .

Preferably, the valves 21 and 22 are of unidirectional type, and may be calibrated so as to have the opening and/or the closing thereof take place at preset values of pressure or of pressure gradient between the region 15 and the tire.

The control of the valves 21 and 22 may be of mechanical or of electronic type.

In fact, it is known that it is possible to preset sensors which gauge the pressure values inside of the tires. On the basis of such gauged values, a controlling and actuating device oversees the opening and/or the closing of the corresponding valves.

This device will not be detailed hereinafter as it may easily be understood by those skilled in the art.

The operation principle underlying the rim according to the present invention will be described hereinafter. During use, the tire will have been inflated to a pressure PI, whose value should be kept as constant as it is possible.

Advantageously, the connecting members 5 are aeriform-filled by the valve 20, in particular, at least one thereof is aeriform-filled to a pressure P2>P1.

When the pressure inside of the tire falls below the desirable value PI (optionally with a margin to be set) , the corresponding valve 21 opens (or is opened by the controlling and actuating device) .

Since inside of the region 15 the aeriform is subjected to a pressure P2>P1, the latter tends to be outletted towards the tire, inflating it until the appropriate pressure value PI is restored. Then, the valve 21 is closed again.

Moreover, one or more of the connecting members 5 can advantageously be aeriform-filled at a pressure P3<P1.

Thus, when the tire pressure increases, e.g. due to a temperature increase, the corresponding valve 22 opens (or is opened by the controlling and actuating device) .

Since inside of the corresponding connecting member the aeriform pressure is less than PI, the aeriform could be outletted from the tire towards the member 5, deflating the tire down to the desirable value PI. Then, the valve 22 is closed again.

Hence, it is apparent that the invention enables on the one hand to always have a reserve of aeriform so as to optionally inflate a deflated tire, and on the other hand to have a tank wherein the excess aeriform can be discharged when instead a tire is overinflated.

Moreover, a safety valve 11 is mounted onto the duct 3 of the rim 1. The safety valve 11 is calibrated so as to open when the tire pressure reaches a predetermined threshold, in order to avoid a possible bursting of the same tire in case the pressure thereof continues to rise, e.g. due to a temperature increase. Figures 4 to 6 depict a second embodiment of a rim according to the present invention.

According to such second embodiment, a rim 31 comprises a hub 32, a duct 33 and a plurality of connecting members 35, 36 between the hub 32 and the duct 33.

Unlike the abovedescribed embodiment, in this case the rim comprises two different types of connecting members . A first type of connecting members 35, having a structural function as well, is substantially identical to the one abovedescribed with regard to the first embodiment, hence a detailed description thereof will be omitted. Instead, a second type of connecting members 36 is of removable type .

In fact, it could be advantageous to avail oneself of a certain number of connecting members 36 which, not having a structural function, could be made so as to be more light-weighted and connected to the rim structure, e.g. by screw, joint or other mechanically equivalent alternative systems.

The operation principle underlying such connecting members is substantially the abovedescribed one. In fact, each one of the connecting members 36 defines an inner region 40 apt to contain an aeriform.

By means of valves 41, 42, of the abovedescribed type, a passing of aeriform between the region 40 and the tire is made possible. This passing, which is bi- directional, is controlled on the basis of the gauged pressure values and gradients between the inner region 40 and the tire itself, thereby enabling to keep the tire pressure as constant over time as it is possible.

Onto the duct 33 of the rim it is provided a safety valve 11, apt to automatically open when the tire pressure reaches a predetermined threshold, so as to avoid accidental burstings due to an excessive increase of the pressure thereof.

An advantage of this second embodiment is that of availing oneself, needwise, of a greater number of connecting members and therefore of a greater quantity of reserve aeriform. Moreover, the removable members 36, could also be of the disposable or rechargeable type.

Advantageously, each of such members 36 can easily be removed with no need to remove the tire, merely by acting on a threaded locking ring 50 which fastens each thereof to the hub 32 and then unscrewing them from the duct 33 onto which they are screwed at threaded seats 51 provided therefor.

According to this embodiment, the rim 31 comprises, at each of the removable members 36, an airtight valve 52.

The airtight valve 52 is operated, in particular it is opened, when the member 36 is completely screwed into the seat 51 thereof. To this end, each member 36 provides a projecting member 53 which, when the member 36 is completely screwed into the respective seat 51, acts onto the valve opening it. On the contrary, when the member 36 is unscrewed, the projecting member 53 departs from the valve causing the closing thereof.

Thus, the removable members 36 can be removed and replaced even at inflated tire, with no aeriform discharge.

As abovementioned, the rim according to the present invention can be used with any one aeriform mixture, even with air. However, preferably a lighter-than-air aeriform, in particular Helium, is used.

Thus, actually a further advantageous effect is that of lightening the motor vehicle. In fact, the Helium- filled rims generate an upward thrust opposing to the weight force due to the gravity.

This aspect is particularly advantageous when, as in car races, the attainment of high performances is also related to the weight of a vehicle.

The present invention was hereto described according to preferred embodiments thereof, given by way of example and without limitative purposes.

It is understood that there could be provided other embodiments of the invention, all to be construed as falling within the protection scope thereof, as defined by the appended claims.

Claims

1. A tire rim (1;31) for a motor vehicle comprising a hub (2; 32) for the fastening to the motor vehicle drive, a duct (3,-33) apt to house a tire (4,-34) to be inflated and a plurality of connecting members (5,-35, 36) between said hub and said duct, characterized in that one or more members of said plurality of connecting members (5 ,-35,36) is hollow and such as to define an inner region (15; 40) apt to contain an aeriform, said one or more connecting members (5; 35, 36) further comprising means (21, 22; 41, 42) for the inletting and/or the outletting of said aeriform from said inner region (15;40), apt to open the latter on the inside of the tire mounted onto the rim.

2. The rim according to claim 1, wherein said means (21, 22,-41, 42) for the inletting and/or the outletting of the aeriform comprises one or more valves of unidirectional type.

3. The rim according to claim 2, wherein a first valve (21; 41) of said one or more valves is apt to enable the passing of aeriform from said region (15,-40) towards the inside of the tire.

4. The rim according to claim 2 or 3 , wherein a second valve (22; 42) of said one or more valves is apt to enable the passing of aeriform from the inside of the tire towards said region (15; 40) .

5. The rim according to any one of the claims 2 to 4 , wherein each of said valves (21, 22 ; 41 , 42) is sensitive to pressure gradients and apt to open when said gradients reach a preset value.

6. The rim according to any one of the preceding claims, wherein at least one of said connecting members (5; 35, 36) further comprises a third valve (20) for the inletting of aeriform from the outside into said inner region (15) .

7. The rim according to any one of the preceding claims, wherein at least one of said connecting members (5; 35, 36) is of removable type.

8. The rim according to claim 7, wherein said at least one removable connecting member (36) is fastened to the duct (33) and to the hub (32) by screw devices (50,51) .

9. The rim according to any one of the preceding claims, comprising sensors apt to gauge pressure values inside of the tire.

10. The rim according to claim 9, wherein said means for the inletting and/or the outletting of the aeriform are operated on the basis of said gauged pressure values.

11. The rim according to any one of the claims 7 to 10, comprising a plurality of airtight valves (52), each airtight valve being located at a respective removable connecting member (36) , and being apt to be operated thereby when it is removed and/or mounted.

12. The rim according to claim 11, wherein said at least one removable connecting member (36) comprises a projecting member (53), apt to cooperate with said airtight valve (52) .

13. The rim according to any one of the preceding claims, further comprising a safety valve 11, mounted onto the duct (3,-33), apt to open when the tire pressure reaches a preset threshold.

14. A removable connecting member for rims, characterized in that it defines an inner region (15;40) apt to contain an aeriform, said member further comprising means (21, 22 ,-41, 42) for the inletting and/or the outletting of said aeriform from said inner region (15;40) .

15. A connecting member according to claim 14, comprising means (50,51) for the fastening to the rim.

16. The connecting member according to claim 15, wherein said rim fastening means comprises threaded seats (51) and a threaded locking ring (50) .