TIRE INFLATION SYSTEM

FIELD OF THE INVENTION

This invention is directed towards a new and improved system for automatic replenishment of air lost from a tire while the vehicle in motion and preventing of the tire sudden deflation also the tire keeping within some time in the inflated state.

The invention relates all types of ground wheeled vehicles, including cars, vans, SUVs, jeeps, commercial trucks, heavy-duty and quarry trucks, buses, trolley buses, wheeled agricultural tractors and earthmoving equipment, motorcycles, motor scooters, etc.

STATE OF THE ART

Tires inflation pressure is responsible for many wheeled motor vehicles mechanisms, for example: ride comfort, steering behavior, driving stability, driving safety, economy, the tires durability, traction and ground ability (mainly for cross-country vehicles). It is very important to hold the tires at constant recommended inflation pressure.

Below in the tables 1 and 2 we give several examples.

Table 1

At the same time if. for example, to judge of tubeless tires inflation pressure by eye, you would be off by 30%. It is common knowledge, that in the course of vehicle real exploitation, tires inflation pressure is not constant and reduces due to progressive air leaking through wheel valve, clearances between wheel rim flanges and the tire beds (tubeless tires), pores in the tires, etc. It is known, that even normal new tires typically leak on the order of 25-30% per year.

Therefore, the vehicle owners and drivers must constantly to watch the tires and pump up its periodically. Really, since, as a rule, the tires are checked and inflated by drivers from time to time only, they run at low pressure for certain period of time, resulting in above mentioned negative consequences. Many drivers inflate tires very rarely and drive at "flat" tires for very long distance. Other drivers intentionally pump over the tires (so as to inflate tires as rarely as possible), resulting in the excessive tires wear, non-comfortable ride, the vehicle vibration, etc.

The first step concerning solving of the tire pressure problem is the Tire Pressure Monitoring Systems (TPMS). which currently are used in more and more expend. They provide notification to drivers that their tire pressure has dropped below the level recommended by the manufacturer. For example, in USA it requires all new four-wheel vehicles weighing 10.000 pounds or less must be equipped with the systems by the 2008 model year. The regulation affects passenger cars, sport utility vehicles, pickup trucks and minivans. NHTSA estimates that 120 lives a year will be saved when all new vehicles are equipped with the systems.

However, tire pressure monitoring only tells to driver if his tires have become or are in the process of becoming under inflated. The systems only state the condition and rely upon the driver to remedy the situation. While this information is helpful, there is nothing you can do if you are miles from a service area. Therefore, constant tire inflation is preferable to monitoring as it applies an instant solution to the situation allowing a driver to continue driving with properly inflated tires. A constant tire inflation system is like an insurance policy, assuring driver of maximum fuel economy and tire efficiency by constantly and automatically maintaining tire pressure, even while your vehicle is in operation.

Oldest well known self-inflating system is Central tires inflation devices (equipped with air compressor and air supply lines to each wheel), incorporated in the vehicle chassis, which have found a wide utility in the cross-country and heavy-duty military vehicles and solve the majority of the problems. But its are very complex and expensive, also requires a compressor presence in the vehicle.

Last time more simple aftermarket systems (CTIS - Central Tire Inflation system) are developed and introduced. Among them, for example, the following:

Hendrickson tire inflation system (HTIS) maintains inflation to specified level. Air travels from supply tank through air lines inside axle to wheel-ends. Rotary union allows air to flow from non-rotating axle spindle to rotating hubcap fitting. Hoses connect from hubcap tee to tires. The tank is supplied with air from regular on-board compressor.

The Meritor tire inflation system by Pressure Systems International (PSI) firm automatically monitors and maintains inflation levels. The system disperses as much air as needed to keep a tire inflated until service can be performed.

TIREMAAX system governed by an electronic control unit (ECU) detects low tire pressure and signals the operator to situations or circumstances requiring attention. It responds by directing air from the trailer air tank to one or more tires when the pressure dips below a preset level.

VIGIA system informs the driver of the condition and the location of the problem in the case of any pressure loss in one or more tires. The air loss automatically activates the pneumatic compensation process and ensures the correct pressure is maintained in all tires, just as they were calibrated at the depot.

Dana Spicer also offers a tire pressure control system. It is designed to allow tire pressure adjustment from the cab. The system produces a better ride, lower step-up height, and reduced driveline maintenance, according to Dana Spicer.

Plurality of patents discloses many design features of central inflation system. Typical among such systems are those which allow an operator to vary the pressure within a vehicle's

tires as desired. Such systems are disclosed by U.S. Pat. No. 2,634,783, issued to Turek; U.S. Pat. No. 2,989,999 issued to Holbrook; U.S. Pat. No. 3,276,502 issued to Ruf; and U.S. Pat. No. 4,418,737 issued to Goodell et al. Among such patents also are the US patents 5587698. 4582108, 4498515, 5313995, 6425427, 2004244896, 2004221917, 2004055291, 2003216845, 6145559, 2004000364, 6585019 and European and Japanese patents WO9958353, DE19961020, EP1371506, EP0297837, EP1362716, WO0170521, DE10031596, WO0034060, JP10193936, JP2003335114.

In each of these prior art central tire inflation systems, air is provided from an air compressor (conventional compressor intended for air brake and suspension) located within the vehicle to the rotating tires via the use of rotary pneumatic joints and seals. They are complex, expensive and are employed practically in heavy trucks initially equipped with air compressor.

Other systems are based on any compressors (air pumps) built-in to the separate wheel. Among them most well-known is Cycloid system, which has been launched in 1997. The system comprises inertial pump in initially was intended for heavy-duty tractor/trailers. The AutoPump pump system for automobiles, SUV's, and light trucks is a smaller version of the heavy-duty pump, with the added feature of incorporating an electronic tire pressure monitoring system that communicates with the vehicle console using wireless technology. Cycloid Company has also developed proprietary "smart analysis" software to allow early detection of tires with air loss problems.

There is range of the patents disclosing of the system containing the air or nitrogen reservoir installed on the wheel. Among then the following: US4067376, US5411051, US5355924, US5413159, EP0621144, US5293919, US2005000587. Some companies have developed the prototypes of such system.

True, in practice it is known only PIRELLI SAFETY WHEEL SYSTEM, which re-inflates a motorcycle's tire in the case of either a puncture or a loss of air pressure. It comprises three elements: a special rim with an internal tube containing compressed air; a valve that

regulates the passage of pressure between the tube and the tire; and the Pirelli Bike X- PRESSURE™ system, which monitors the pressure and temperature inside the tire.

In spite of the fact, that tubeless tires elastic rubber lining allows the tires to deflate relatively slowly (sometimes), the problem of running vehicle safety in the case of tubeless tires sudden damage, that may result a possible accident, remains to face the vehicle designers and drivers. In more extent it concerns tube tires.

For many years the vehicles and tires manufacturers struggle to develop a run-flat tire and reach some positive results. However, the above tires mass-scale application faces a lot of problems, such as cost, weight, rolling resistance, reliability, convenience of using and so on, and they are not used widely currently.

Among these developments, it should be mentioned the following:

In the middle of 70-s the run-flat Total Mobility Tire (TMT) has been developed by Dunlop Company. This tire is mounted in a special separable wheel rim. Also several small containers, filled a liquid lubrication, are installed in the special ring, which, in turn, is placed in the wheel rim, that is inside the tire. In the case of the tire puncture and the air pressure falling, the tire is deformed in such way that upper tire lips roll on inner surface of the tire tread.

In the middle of 80-s US Continental Company has developed an interesting run-flat tire Conti Tire System (CTS). In this case, the tire grips (bead seat), as differentiated from all existing tires, are placed outside the wheel rim. When the tire is deflated, the central outward-projecting portion of the wheel rim runs on the inner surface of the tire tread.

The coming generation of run-flat tire was the DIP tire, proposed by Italian Pirelli Company. This tire is mounted in a special narrow rim and, in the case of puncture, operates like the TMT tire. However, as differentiated from the TMT, the DIP has a triangular form and more thick sidewalls.

Latest run-flat design is Extended-mobility tire (EMT) by Goodyear Company, which has been demonstrated first in 1997. The EMT is built from a rubber composite, containing more

than 100 chemicals. The tire principle future is very simple: the sidewall is so stiff that it can support the vehicle even the tire is complete deflated. The EMT fits regular wheels, but the tire price and weight is increased by 20% and 10% correspondingly.

Bridgestone Corporation of Japan has developed a system, Aircept (assistant inner ring interceptor), for its line of wide base single radials. The Aircept unit fits around the rim inside the radial. Any sudden loss of pressure causes the unit to expand and support the load. The system begins to expand if tire pressure drops below a specified level. By the time a total loss of pressure occurs, the unit has expanded to fill the interior of the tire, supporting the load. The system operates in conjunction with a tire pressure monitor that alerts the driver to the loss of air pressure.

Patents and applications, which disclose run-flat tire design, are US2004035513, US2004016490, US2004025995, US2004140032, DE19923070, WO2005023565, JP2004330985, JP2004255937, FR2822413, etc.

It should be mentioned although above mentioned automatic tire inflation systems and run- flat systems are technically feasible for their intended purposes, they possess inherent economic and practical deficiencies, which detract from their overall effectiveness in the marketplace. Beside, means, which combined both self-inflating and run-flat properties, practically are absent.

Taking into account the above said it is possible to conclude the following. At the present there is not any cheap practicable effective means for the tire self-inflating in the course of motion so as to provide the slow air lost compensation and at the same time to prevent at least the tire sudden emergence deflation in the case of puncture or other damage.

SUMMARY OF THE INVENTION

The first object of the invention is maintaining a desired inflation pressure within the tubeless or tube tire during the vehicle normal long-time operation. To do so the separate first control means regulates the amount of air pressure in a tire. When pressure within the

tire drops below the selected threshold, gas is directed from the first gas generating means into the tire or tube keeping it inflated to the desired pressure.

The second object of the invention is to provide the tire with normal travel in the case of the tire puncture or other damage, when the gas escapes from the tire very quickly. When pressures within the tire as the result of fast escape drops below a selected threshold gas stored in the both the first and the second reservoirs is released fully into the tire or tube keeping the tire inflated. Therewith, the tube plays role of an airbag.

The system generally comprises at least two separate gas generating means of lightweight materials, such as, but not limited to, aluminum, magnesium, titanium, steel, composite, etc.. fitted on each of the road wheels of said vehicle or installed into the vehicle chassis or body by pair, special or conventional tube (airbag) installed inside the tire arid hydro mechanical or electronic control means to transfer said gas from said high pressure reservoirs into the tire or tube. Therewith, the first reservoir serves for gas supply to the tire for replenishment of normal air lost during the vehicle exploitation, whereas the second is intended exclusively for the gas supply to the tire or tube in emergence cases of the tire or tube puncture or other damage. The both gas generating means are filled with liquid gas mainly carbon dioxide, which possesses properties to convert from liquid phase to gaseous phase when it is supplied to said tire or inner tube.

There are two versions of the proposed system.

In the first version both the high-pressure reservoirs and control means generally are attached to the wheel rim or is built-in into anew-constructed cast, forged or stamped wheel rim. Also the above assembly can be installed on the wheel decorative cover as separable or integral component. Since the reservoirs are rotated with the tire together the gas easy is supplied to the tire through simple gas pipeline.

The provision is made to equip the second gas generating means with a container containing a sealing agent, for example a latex dispersion. The sealing agent is supplied into the tire by air drive immediately as well as by an compressed air feed through a Venturi valve,

underpressure creation within the said container and drawing the sealant to the tire by ejection.

This version also includes a modification, in which an inner tube (it plays the role of emergency airbag) is installed in the conventional tubeless tire (initially, the tube is installed in the tire in folded condition). This tube is inflated in emergency the tire puncture or other damage from the second reservoir.

In the second version both the high-pressure reservoirs and control means generally are installed into the vehicle chassis or body and the gas is supplied to the tire through hose, which runs in the vehicle chassis and inside the axles to their proprietary hubcaps and rotary union that pass the gas from stationary axle to the rotating wheel. The above modification with inner tube (air bag) is available in this version also. . ., - _i

The device mounted on the wheel due to low weight and small radius from the rotating axle is balanced easy such as not to affect the wheel common balance. The weight of the components added to the wheel, e.g. reservoir, filter, valves, gas communications is balanced by distributing those components around the wheel and conventional weights.

Thus, all above the invention versions and modification enable to use the proposed system for three functional purposes simultaneously: to provide the tire with constant pre-assigned pressure during its normal exploitation, to provide gas lost compensation during some time in the case of minor tire or rim damage and to prevent the tire from sudden deflation in the emergency cases. Provision is made for the above versions to comprise monitoring system providing permanent automatic detection of the tire pressure also pressure inside the gas generating means and generating of signals to monitoring devices placed on-board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of the components and layout of control circuit of a first preferred embodiment of the present invention comprising two gas generating means (reservoirs) and hydro- mechanical control valve installed onto the vehicle wheel.

FIG. 2 is a schematic cross-sectional view of the components and layout of control circuit of a first preferred embodiment of the present invention comprising two gas generating means (reservoirs), hydro- mechanical control valve and additionally container with liquid sealant composition installed onto the vehicle wheel.

FIG. 3 is a schematic cross-sectional view of the components and layout of control circuit of a second preferred embodiment of the present invention comprising itwo ^* gas generating means (reservoirs), hydro-mechanical control valve and inner inflatable ^' tube installed onto the vehicle wheel.

FIG. 4 is a schematic cross-sectional view of the components and layout of control circuit of a third preferred embodiment of the present invention comprising two gas generating means (reservoirs) and electronic control/monitoring system installed onto the vehicle wheel.

FIG.5 is a schematic cross-sectional view of the components and layout of control circuit of a fourth preferred embodiment of the present invention comprising two gas generating means (reservoirs) installed the vehicle on-board and hydro-mechanical control valve installed onto the vehicle wheel.

DETAILED DESCRIPTION OF THE INVENTIOM

The above objects and features of the present invention will become, more- understood from the following description of preferred embodiments and the accompanying drawing figures.

FIG. 1 (A and B) shows a first preferred embodiment of the present invention comprising two gas generating means (reservoirs) and hydro-mechanical control valve installed onto the vehicle wheel.

The proposed system comprises two high pressure reservoirs (9) and (18) (FIG. 1), which serve as sources of compressed gas. They are installed onto wheel (13). Both reservoirs are filled with carbon dioxide (27) in liquid form and contain the gas vapo.r (21) under pressure. Therewith, the reservoir (18) serves as gas source at air slow escape compensation and at emergence case, whereas the reservoir (9) operates at emergence mode only.

The reservoirs (18 and 9) are joined through the pipelines (44 and 72) correspondingly to control spool valve (35). The valve (35) is equipped with a spool (39), having two positions. Two output channels are connected with the tire chamber by pipe (41). Right end of the valve spool (39) interacts with valve spπng (71). Left end of the spoόl (39) is under tire air/gas pressure constantly, since it is connected with the pipeline (41)tjόined to.the tire 7.

The appliance operates in the following manner. Initially (it is not shown in the view A on the FIG. l) the control valve is at position of normal operation. That time two forces impact to the valve spool (39) ends: the spring (71) force acts to right end and tire air/gas pressure impacts to the left end. Therewith, the gas impacting to the spool υom pipeline , (41) is under pressure of the tire air (32), because the valve (39) end space is connected with the pipeline (41), leaded to the tire (7).

Area of the left spool piston and the spring (71) rate are so matched that the spool is settled in position, when the left piston is near output channel connected with the pipeline (41).

If the air/gas pressure in the tire corresponds to the normal level (it is not shown on the FIG. 1 ) the spool (39) is placed in an intermediate position, when it close the channel joined to the pipeline (44) and the channel joined to the pipeline (41). This time the gas is not supplied from the reservoirs (9) and (18) to the tire (7). "' ^* ' ^τ -' ^*' " , _^

If the gas pressure in the tire is less than nominal required pressure (FTG. I- A), the spool (39) under the action of the spring (71) moves toward the left and is settled in position, when the gas from the reservoir (18) flows through pipeline (44) and corresponding the valve channel unobstructed to the pipeline (41) and hereafter to the tire (7). This time oneway valve (47) does not enable the gas to flow back to the spool valve (35) chamber.

When the air pressure in the tire reaches to nominal air pressure value, the spool (under action of the gas to left spool end) moves toward the right and closes once more the channels connected with pipelines (44) and (41).

Pre-assigned desired nominal gas pressure is available by matching of the spring rate.

At this mode the gas is directed from the reservoir (18) to the tire only in order to replenish tire pressure in response to pressure falling due to air permanent leaking.

In the case of the tire puncture or/and other damage the system operates in emergence mode (FIG. l - B). This time fast air/gas leakage takes place and the gas pressure falls on a large extend. That time the spring (71) imparts the spool (39) to move it to extremely left position. When the spool is situated in extremely left position the gas continues to be supplied from the reservoir (18) to pipe (41) and at the same time the gas is supplied from the reservoir (9) through pipeline (72) to the pipeline (41) to the tire (7). As the result the tire is inflated from both reservoirs (9) and (18) or at least from the reservoir (9) to provide the tire (7) immediate inflation.

FIG. 2 shows the second preferred embodiment of the present invention equipped additionally with container (25) filled with any liquid sealant (air/gas leakage compensation mode is shown only). In this case gas. which goes from the reservoir (9) to the tire in emergence mode is supplied initially to the container (25) filled with liquid sealant agent, for example a latex dispersion. Further the sealant agent goes to the tire by air drive immediately or by compressed air feed through a Venturi valve. In last case underpressure is created within the said container (25) and it draws the sealant agent to the tire (7) by ejection.

The third preferred embodiment is shown on the FIG.3. In distinction from the first embodiment this design is intended for tubeless tires only. The embodiment includes the following additional components.

A special tube (gas bag) (30) is installed inside the tire (7). The tube is wrapped with an elastic belt with sectional distance spacer (37). Initially the tube-belt assembly is in laid

condition (as it is shown in left view on the FIG.3- A). Other differences from embodiment shown on Fig. 1 is the reservoir (18) is intended to supply with gas the tire 7 chamber only whereas emergency reservoir (9) is intended for the tube (7) inflation only. Corresponding changes are introduced in the valve (35) design. Pipeline (45) is connected with the tube whereas pipeline (41) is connected with the tire (7) chamber through conventional stem valve.

The system according this embodiment operates in the following manner:

Initially (it is not shown in the view A on the FIG.3) the control valve (35) is at position of normal operation. That time two forces impact to the valve spool (39) ends: the spring force acts to right end and tire (7) air/gas pressure impacts to the left end. Therewith,, the gas impacting to the spool from pipeline (41) is under pressure of the tire air/gas, because the valve end space is connected with the pipeline (41), leaded to the tire (7).

Area of the left spool piston and the spring (71) rate are so matched that the spool 25 is settled in position, when the left piston is near output channel connected with the pipeline

(41).

If the air/gas pressure in the tire corresponds to the normal level (it is not shown on the FIG. 1) the spool is placed in an intermediate position, when it close the channel joined to the pipeline (44) and the channel joined to the pipeline (41). This time the gas is not supplied from the reservoirs (18) and to the tire (7). ^; "

If the gas pressure in the tire is less than nominal required pressure' (FIG. 3- A), the spool (39) under the action of the spring (71) moves toward the left and is settled in position, when the gas from the reservoir (18) flows through line (44) and corresponding the valve 35 channel unobstructed to the pipeline (41) and hereafter to the tire (7).

When the air/gas pressure in the tire (7) reaches to nominal air pressure value, the spool 39 (under action of the gas to left spool end) moves toward the right and closes once more the channels connected with pipelines (44) and (41).

Pre-assigned desired nominal gas pressure is available by matching of the spring rate.

At this mode the tube is in the folded condition and the gas is directed from the reservoir (18) to the tire (7) only in order to replenish tire pressure in response to pressure falling due to air permanent leaking.

In the case of the tire puncture or/and other damage the system operates in emergence mode (FIG.3 - B). This time fast air/gas leakage takes place and the gas pressure falls on a large extend. That time the spring (71) imparts the spool (39) to move it to extremely left position. When the spool is situated in extremely left position the gas is supplied from the reservoir (9) through pipeline (45) to the tube (30). As the result the tube (30) is immediately inflated and the vehicle can drive without any restriction. At the tube (30) inflation the spacer (37) is placed between the tire (7) and tube (30) in order to prevent the tube (30) damaging (when it is inflated) by any hard subject, which after puncture still sticks UD in the tire (7). The spacer (37) provides proper distance between the tube (30) outer periphery and interior tire (7) surface. This distance in combination with tire (7) tread thickness protects the tube (30) after puncture against, for example, nail.

FIG. 4 shows another preferred embodiment of the present invention based on control means comprising the electronic pressure and temperature sensors, electronic control unit (ECU) and electronic control valves, also monitoring system for watching of the air/gas current pressure in the tire and both reservoirs (18) and (9).

This embodiment includes two electronic sensors (85 and 89) mounted onto .pipelines (107 and 109), which constantly monitors pressure and temperature inside the both' reservoirs (18 and 9). Sensor (95) measures pressure and temperature inside the tire (7) chamber immediately. The sensors are supplied by energy from an electric battery, installed onto the wheel (not shown in the FIG. 4). Signals from the sensors are transmitted by wires to miniature electronic control unit (ECU) (101), mounted onto wheels.

The ECU (101) fulfills two functions: to provide properly the tire with gas from the reservoirs (9) and (18) to supply signal to monitoring system.

To solve the first task the ECU generates a command to at least one electronic-controlled valve (1 15), which switches the gas flow according to built-in algorithm: it provides the gas

13

- 't '

direction from the reservoir (18) to compensate air/gas slow escape from the tire (7) and the gas direction from the reservoir (9) in emergence case.

To solve the second task the ECU causes a radio frequency (RF) or sonic or ultrasonic signal to transmit monitoring information to driver through antenna (130), placed onto the wheel and antenna (132) mounted in close proximity to the wheel on the vehicle structure or undercarriage and further by wires to a device (90) placed in the vehicle cabin or salon.

In a modification of this embodiment the vehicle is equipped with single central on-board ECU. In this case the signal from the sensors installed onto the wheels the signal is transmitted from the wheel antenna to a receiver installed near each wheel onto the vehicle body or undercarriage and afterward the receiver send signal to a the central ECU by wire. The central receiver processes obtained signals and send back command to the wheel for the gas flow control and at the same time signal to monitoring device in cabin or salon.

The system operates in the following manner:

During normal operation if the gas pressure in the tire (7) is less than nominal required pressure the ECU (101) opens the valve (115) to replenish the gas losses from the reservoir (18) through pipelines (107 and 110). When the air pressure in the tire reaches to pre- assigned desired nominal gas pressure the ECU (101) and control valve (115) close the pipeline (107) and the pressure is stabilized.

When tire (7) is punctured and fast gas leakage takes place the gas pressure falls on a large extend in short period. That time the ECU (101) switch on the valve (115) and the tire immediately is connected with both reservoirs (18) and (9) and gas is supplied through the pipelines (107), (109) and (110).

Another preferred embodiment is shown in FIG.5. The embodiment comprises pair of onboard central gas generating means and central control system (instead of the number of reservoir pairs and control systems installed on the each wheel) and gas circuit for the gas supply to each wheel.

The gas storage reservoirs (9 and 18) differs from the above described individual wheel gas generating means by volume and size only. Design and function of hydro-mechanical control valve (35) is the same also. Therewith, circuit for the gas distribution among the wheels is not different from known Central Tire Inflation System (CTIS), but gas storage reservoirs is used instead of compressor driven by the vehicle engine. This system runs air/gas hoses in the vehicle chassis (150) and inside the axles to their proprietary hubcaps (171). Each hubcap has a rotary union (for example with graphite seal) that pass the gas from stationary axle to the rotating wheel and automatically adjusts for wear.

In different from all above embodiments the gas generating means supply the gas in all cases to the general circuit (155) and further the gas flows to the wheel. The control system responds to the pressure drop in the general air/gas circuit which in turn is function of pressure in each tire.

As for the rest all operation principles are similar to the above described embodiments.

Although the description above contains much specificity, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.

For example, instead of reservoir pairs it could be single reservoir with two separate high pressure chambers. Or other example, control valve can has any other arrangement as compare to given spool design, or several valves can be applied, etc. Thus, the scope of the invention should be determined by the appended claims in the formal application and their legal equivalents, rather than by the examples given.