Tire pressure management system

A tire pressure management system includes at least an axle enclosing a pressurized fluid, a hubcap supported by the axle and having an interior and an exterior, a rotary union axially aligned with the axle and mounted to the hubcap, the rotary union includes at least, a fluid conduit having upstream and downstream ends, a first bearing and a second bearing, the first bearing in pressing engagement with the fluid conduit and adjacent the downstream end of said fluid conduit, the second bearing in pressing engagement with the fluid conduit and adjacent the upstream end of said fluid conduit, and a first and second seal, the first seal is disposed between the first bearing and the downstream end of the fluid conduit, and the second seal is disposed between the second bearing and the upstream end of the fluid conduit.

FIELD OF THE INVENTION

The present invention relates to the field of tire pressure maintenance. More particularly, the present invention relates to the management of tire pressure of tires supporting tractor trailers, even while the trailers are traveling along a roadway.

BACKGROUND OF THE INVENTION

The present invention relates to an improved rotary union for use in a central tire pressure management system for automatically maintaining the inflation pressure of the pneumatic tires on moving vehicles such as tractor trailers. Typically, tractor trailers utilize the air compressor on the tractor as a source of pressurized air to activate braking systems. The compressor directs air to the reserve air brake tank on the trailer, which generally corresponds to the range of typical inflation pressures in the tires used on trailers. Air from the reserve air brake tank is first directed to the braking system to maintain the air pressure in the braking system. In conventional tire inflation systems, excess air is directed from the tank through a pressure protection valve to a control box for the tire inflation system. The pressure protection valve only opens to direct the air to the control box when excess air pressure is present, thereby preventing air from being directed to the tire inflation system which is needed for the trailer braking system.

The control box contains a pressure regulator which is set to the cold tire pressure of the particular tires on the trailer so as to supply air to the tires at the desired pressure level in the event of a leak. Air is directed from the control box to the leaking tire through one of the trailer axles, which either carries an air line from the control box, or is sealed and functions as an air conduit. The pressurized air carried by the axles communicates with each pair of trailer tires mounted thereon through a rotary union assembly by which air flow is directed from a stationary air line to the valve stems on the rotating tires. Pressure responsive valves are employed between each rotary union assembly and its associated tires so that upon the occurrence of a leak in one of the tires, the resulting pressure loss will cause one of the valves to open and allow air flow from the rotary union assembly to pass therethrough to the leaking tire.

As tire inflation systems become adopted for broader uses, reliability and ease of maintenance, as well as an ability to manage under inflated as well as over inflated tires have emerged as important demands from the industry, accordingly improvements in apparatus and methods of installing tire inflation systems are needed and it is to these needs the present invention is directed.

SUMMARY OF THE INVENTION

In accordance with preferred embodiments, a tire pressure management system includes at least an axle housing enclosing a pressurized fluid, a hubcap supported by the axle and having an interior and an exterior, and a rotary union axially aligned with the axle and mounted to the hubcap from the exterior of the hubcap. Preferably, the rotary union including at least a fluid conduit, the fluid conduit having a downstream end and an upstream end, a pair of bearings, each of the pair of bearings providing an inner race and an outer race, each inner race of the pair of bearings is preferably in pressing communication with the fluid conduit, a first bearing of the pair of bearings is preferably adjacent the downstream end of said fluid conduit, and a second bearing of the pair of bearings is preferably adjacent the upstream end of the fluid conduit.

Preferably, the tire pressure management system further includes at least a pair of fluid seals, a first seal of the pair of fluid seals engage an external surface of the fluid conduit and is preferably disposed between the first bearing and the downstream end of the fluid conduit, and a second seal of the pair of fluid seals engaging the external surface of the fluid conduit and is preferably disposed between the second bearing and the upstream end of the fluid conduit.

These and various other features and advantages that characterize the claimed invention will be apparent upon reading the following detailed description and upon review of the associated drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS

It will be readily understood that elements of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Referring now in detail to the drawings of the preferred embodiments, the rotary union assembly10(also referred to herein as assembly10, and rotary union10) of the first preferred embodiment, while useable on a wide variety of movable vehicles employing stationary axles for automatically maintaining the inflation pressure of the pneumatic tires thereon, is particularly adapted for use on tractor trailers. Throughout the remainder of this disclosure, sign numbers will be used to show the same part of an invention appearing in more than one view of the drawing shall be designated by the same reference character, and the same reference character shall not be used to designate different parts. It is noted that there are no dimensions associated within any of the drawing. As such, a particular part of the invention may have an appearance of being slightly different in form from drawing to drawing, however the function that part plays in the limitations of the invention remain the same. Accordingly, sign numbers such as ten (10), ten prime (10′), and ten double prime (10″) are, from the point of view of the invention, identical and interchangeable with one another, because the function served by that part, such as10,10′, or10″ remain the same within the invention.

Accordingly, the assembly10of the first preferred embodiment will be described in conjunction with a pair of adjacent vehicle tires12and14mounted on a stationary tractor trailer axle housing16(also referred to herein as trailer axle housing16, and axle housing16). While identical rotary union assemblies10are provided at the end of each axle on the trailer to maintain the inflation pressure of the tires carried thereby, in each: the preferred embodiment; the alternate preferred embodiment; and the alternative preferred embodiment, reference will be made to only one such assembly and the pair of tires it services.

Preferably, the trailer axle housing16which carries tires12and14is sealed and functions as a source for pressurized fluid, else houses an air supply line18to supply air to the rotary union assembly10, also referred to as10′ within this specification and in various drawings of this specification and as identified, or shown in the various drawings, rotary union assembly10differs from rotary union assembly10′ in esthetic presentation only; they are functional equivalents. A fluid supply line20preferably provides air under pressure to the interior of the axle housing16, else to an air supply line18, from the conventional air compressor on the tractor via a standard pressure protection valve and control box (not shown) to pressurize the axle housing16, else to pressurize the air supply line18, at the cold tire pressure of the trailer tires.FIG. 1further shows that the axle housing16supports an axle plug22, which in turn supports a push to connect fluid fitting24. Preferably, the push to connect fluid fitting24is attached to and in fluid communication with a fill tube26, which in a preferred embodiment is a flexible fill tube26. As identified, or shown, in the various drawings, fill tube26differs from fill tube26′ by esthetic presentation only; they are functional equivalents. Preferably, the flexible fill tube26is connected to a fluid conduit28, which supplies pressurized air to the rotary union assembly10. Preferably, the flexible fill tube26is secured to the fluid conduit28, by a compression fitting30. As those skilled in the art would know, a compression fitting, or alternate mechanical means, could serve the function of the push to connect fluid fitting24. As identified, or shown, in the various drawings, fluid conduit28differs from fluid conduit28′ by esthetic presentation only; they are functional equivalents.

In a preferred embodiment, the rotary union assembly10is mounted to a hubcap32, from an exterior34of the hubcap32, and provides pressurized air, by way of an air delivery channel36, to tire pressure hose fittings38that are secured to tire pressure hoses40. Each tire pressure hose40supplies the pressurized air to tire valve stems42of tires12and14. Preferably, the rotary union assembly10provides a seal access aperture39that cooperates with a removable seal access cover44, which mitigates escapement of pressurized fluid from the air delivery channel36, the tire pressure hoses40, and the tires12and14.

As seen inFIGS. 2 and 3, the fluid conduit28provides a downstream end48and an upstream end46, and the rotary union assembly10further preferably includes a pair of bearings50, in which each of the pair of bearings50provides an inner race and an outer race. In a preferred embodiment, a first bearing52, of the pair of bearings50, is adjacent the downstream end48, of the fluid conduit28, while the second bearing54, of the pair of bearings50, is adjacent the upstream end46, of the fluid conduit28. As identified, or shown, in the various drawings, first bearing52differs from first bearing52′ by esthetic presentation only; they are functional equivalents, and as identified, or shown, in the various drawings, second bearing54differs from second bearing54′ by esthetic presentation only; they are functional equivalents. Further, as seen inFIG. 2, the fluid conduit is a single, unitary component between the upstream end46, and the downstream end48.

FIG. 2further shows that in a preferred embodiment, the rotary union assembly10, further includes a pair of fluid seals56, with a first fluid seal58, is preferably disposed between the first bearing52, and the downstream end48of the fluid conduit28, while the second fluid seal62, of the pair of fluid seals56, is preferably disposed between the second bearing54, and the upstream end46, of the fluid conduit28. In a preferred embodiment, the second fluid seal62mitigates transfer of an environment contained within an interior64, of the hubcap32, from entry into the pair of bearings50, and wherein each first seal58and the second seal62of said pair of fluid seals56form a rotary seal63between an external surface60, of the fluid conduit and a bore surface86(ofFIG. 4), of a central bore84(ofFIG. 4), of a rotary union housing76′. As identified, or shown, in the various drawings, external surface60differs from external surface60′ by esthetic presentation only; they are functional equivalents. Preferably, the pair of fluid seals are lip seals56.

FIG. 2still further shows that in a preferred embodiment, each of the pair of fluid seals56(58and62), provide a base portion (66and68respectfully), and the rotary union assembly10, further includes: a first fluid seal restraint70, which is disposed between the first bearing52, and the base portion66of the first fluid seal58, and in pressing engagement with the external surface60, of the fluid conduit28, which, as can be seen byFIG. 2, means the first seal restraint70, is disposed between the downstream end48of the fluid conduit28and the base portion66of the first fluid seal58; and a second fluid seal restraint72, which is disposed between the base portion68of the second fluid seal62and the upstream end46, of the fluid conduit28, the second fluid seal restraint72further in pressing engagement with the external surface60of the fluid conduit28. Further, as identified, or shown, in the various drawings, the first fluid seal restraint70differs from the first fluid seal restraint70′ by esthetic presentation only; they are functional equivalents, and as further still identified, or shown, in the various drawings, the second fluid seal restraint72differs from the second fluid seal restraint72′ by esthetic presentation only; they are functional equivalents.FIG. 2still further shows that the rotary union10, preferably includes a bearing spacer74, disposed between the first bearing52and the second bearing54of the pair of bearings50. The bearing spacer74provides stability of the first and second bearings (52,54) during the process of pressing the pair of bearings50into a rotary union housing76, of the rotary union assembly10. As identified, or shown, in the various drawings, bearing spacer74differs from bearing spacer74′, or bearing spacer74″ by esthetic presentation only; they are all functional equivalents of one another. Also, as identified, or shown, in the various drawings, rotary union housing76differs from rotary union housing76′ by esthetic presentation only, and as further shown by the various drawings presenting the rotary union housing (76,76′), the rotary union housing (76,76′) is a single component, and the rotary union housing (76,76′) are functional equivalents.

As discussed hereinabove, in a preferred embodiment, the second fluid seal62, mitigates transfer of an environment contained within an interior64, of the hubcap32, from entry into the pair of bearings50. However, if the environment within the hubcap32elevates in pressure, a spring loaded pressure relief valve78(such as a poppet valve), else a pressure relief seal80(ofFIG. 9), confined by an excess pressure collection chamber82(which is provided by the rotary union housing76, and is in contact adjacency with the exterior34, of the hubcap32, and shown byFIGS. 2 and 3), activates to relieve the pressure present in the pressure collection chamber82, to atmosphere. That is, when the pressure contained by the pressure collection chamber82reaches a predetermined pressure level, which in a preferred embodiment is in the range of 5 to 8 PSI.

FIG. 4shows a preferred embodiment that preferably includes at least the rotary union housing76′ supporting and confining the fluid conduit28, within a central bore84(also referred to herein as channel84), of the rotary union housing76′. The fluid conduit28preferably provides the downstream end48and the upstream end46. Further shown byFIG. 4is the pair of bearings50; each of the pair of bearings50provides an inner race and an outer race. Each inner race of the pair of bearings50, is in pressing communication with the external surface60, of the fluid conduit28, and each outer race of the pair of bearings50, is in pressing communication with a bore surface86(also referred to herein as wall86), of the central bore84, of the rotary union housing76′. The first bearing52, of the pair of bearings50, is adjacent the downstream end48, of the fluid conduit28, and the second bearing54, of the pair of bearings50, is adjacent the upstream end46, of the fluid conduit28.

FIG. 4further shows that in a preferred embodiment, the rotary union10′ preferably includes a pair of fluid seals56, the first fluid seal58, of the pair of fluid seals56, engages the external surface60, of the fluid conduit28, and is disposed between the first bearing52, and the downstream end48, of said fluid conduit28. The second fluid seal62, of the pair of fluid seals56, engages the external surface60of the fluid conduit28, and is disposed between said second bearing54, and the upstream end46, of the fluid conduit28. In a preferred embodiment, the first fluid seal58provides the base portion66, and the first fluid seal restraint70, which is in pressing contact with the external surface60of the fluid conduit28, abuts against the base portion66, of the first fluid seal58, to maintain the relative position of the first fluid seal58, adjacent the bore surface86, of the central bore84; and the second fluid seal62, provides the base portion68, and the second fluid seal restraint72, which is in pressing contact with the external surface60of the fluid conduit28, abuts against the base portion68, of the second fluid seal62, to maintain the relative position of the second fluid seal62, adjacent the bore surface86, of the central bore84. In a preferred embodiment, the rotary union housing76′ further provides a fluid distribution chamber88(also referred to herein as a fluid chamber88), which is in fluid communication with the downstream end48, of the fluid conduit28. The fluid chamber88, receives pressurized air from the fluid conduit28, and transfers the received pressurized air to the tires12and14(ofFIG. 1).

FIG. 5shows that in a preferred embodiment, the hubcap32provides an attachment aperture90. The attachment aperture90is preferably disposed between the interior64and the exterior34, of the hubcap32. The attachment aperture90provides an axis of rotation, which is preferably substantially aligned with an axis of the axle16(ofFIG. 1). Additionally, the rotary union housing76′ provides at least an attachment member92, which preferably is in mating communication with the attachment aperture90.FIG. 5further shows that the fluid conduit28provides a fluid communication portion94, which extends beyond the attachment member92, and into the interior of said hubcap32.

FIGS. 6 and 7show the push to connect fluid fitting24, of a preferred embodiment. The push to connect fitting, model No. 1868X4 by Eaton Weatherhead, of Maumee, Ohio is an example of a push to connect fitting of the type found useful in a preferred embodiment.FIG. 7shows that in a preferred embodiment, two push to connect fluid fittings24, are secured to the axle plug22. In a preferred embodiment, one of the pair of push to connect fluid fittings24is in fluid communication with the air supply line18, while the other is in fluid communication with the fill tube26.FIG. 7shows that in a preferred alternate embodiment, the axle plug22, provides a pressure transfer conduit96, which is used to disburse pressurized air, which may accumulate in the interior64, of the hubcap32(both ofFIG. 4), back into the axle housing16, when the air supply line18, is utilized to convey pressurized air to the rotary union10(ofFIG. 2).

FIG. 8depicts an alternate preferred embodiment of the present invention, in which the fluid conduit28, provides the bearing spacer74, and the rotary union housing76′″ provides the first fluid seal restraint70. Additionally, in a preferred embodiment, the fill tube26is a flexible fill tube formed from a polymer, such as a polyurethane based material, else a metallic material, such as a shape memory alloy.FIG. 8further shows that when the flexible fill tube26is connected to the push to connect fluid fitting24, an anti-rotational means98is incorporated into the rotary union10′″. Preferably, the anti-rotational means98has a first end100, and a second end102. The first end100of the anti-rotational means98, is secured to the flexible fill tube26, adjacent the fluid communication portion94. The second end102, of the anti-rotational means98, connects to the push to connect fluid fitting24. Preferably, the anti-rotational means98mitigates rotation of the fill tube26, when the rotary union housing76′″, in conjunction with the hubcap32, rotates about the fluid conduit28. By example, but not by limitation, a coiled spring has been found useful as the anti-rotational means98, in an alternate example, but not by way of limitation, a torsion bar104(ofFIG. 9) has been found useful to serve as an anti-rotational means98. However, as those skilled in the art will appreciate, any of a host of mechanical structures, which serve to mitigate rotation of the fill tube26, when the rotary union housing76′″, in conjunction with the hubcap32, rotates about the fluid conduit28may be employed to serve this purpose.

In an alternate preferred embodiment, in addition to the fluid chamber88, the rotary union housing76′″, further provides the air delivery channel36, which is in fluid communication with, and extending radially from, said fluid chamber88, as shown byFIG. 8, the fluid conduit28, further provides a retention barb106, protruding from the fluid conduit28, and communicating with an interior surface108, of said flexible fill tube26. The retention barb106, mitigates an inadvertent removal of said flexible fill tube26, from the fluid conduit28. The retention barb106, is preferably positioned adjacent to, and downstream from the compression fitting30, as shown byFIG. 9.

FIG. 10shows a tire pressure management system110, which preferably includes at least a fluid pressure controller112, which in a preferred embodiment controls the flow of pressurized air into and out of the tires12and14. The source of the pressurized air is a trailer air tank114. The trailer air tank114, is in fluidic communication with a tire pressure tank116. The pressurized air from the trailer air tank114passes through an air regulator118, and then through an air inlet control valve120, operating under the control of the fluid pressure controller112. In a preferred embodiment, the tire pressure management system110, further includes at least: an air outlet valve122, in fluid communication with the tire pressure tank116, and under the control of the fluid pressure controller112; a tire pressure tank pressure gauge124, in fluid communication with the tire pressure tank116, and in electronic communication with the fluid pressure controller112; and an air pressure supply valve126, in fluid communication with the tire pressure tank116, and under the control of the fluid pressure controller112. Preferably, the air pressure supply valve126, supplies pressurized air to, or conversely, receives pressurized air from the air supply line18, depending on whether the pressure in the tire (12,14), is above or below a desired pressure level.

In a preferred embodiment, pressurized air that flows into or out of the rotary union10, is modulated by a dual flow control valve128. Preferably, the dual flow control valve128, responds to air pressure supplied by the air supply line18, by opening a spring loaded valve member, which allows pressurized air to flow out of the tire (12,14), when the pressure in the tire (12,14), is greater than the air pressure in the air supply line18. Conversely, the dual flow control valve128, promotes the flow of pressurized air into the tire (12,14), when the pressure level within the tire12,14is less than the air pressure in the air supply line18.

FIG. 10further shows that the tire pressure management system110, further preferably includes a tire pressure monitoring sensor130, disposed between the dual flow control valve128, and the tire (12,14), and in electronic communication with the fluid pressure controller112. In a preferred embodiment, the tire pressure monitoring sensor130, measures the level of pressure within the tire (12,14), and relays the measured pressure level to the fluid pressure controller112. The fluid pressure controller112, compares the measured pressure level within the tire (12,14) to a target pressure, maintains the pressure available in the tire pressure tank116at the target level, and directs the air pressure supply valve126, to release pressurized air to the dual flow control valve128, which activates to promote either inflation, or deflation of the tire (12,14), to bring the pressure level within the tire (12,14) into balance with the target pressure level. Once the desired pressure level within the tire (12,14) is achieved, as measured by the tire pressure monitoring sensor, the fluid pressure controller112, directs the air pressure supply valve126, to disengage.

In a preferred embodiment, the fluid pressure controller112, operates both the air outlet valve122, and the air inlet control valve120, to maintain the pressure within the tire pressure tank116, at a predetermined pressure level. For example, but not by way of limitation, if the tire pressure of the tires (12,14) is above the target pressure level, the fluid pressure controller112, will crack open the air outlet valve122, to allow relief of pressure from the system; and if the tire pressure of the tires (12,14) is below the target pressure level, the fluid pressure controller112, will crack open the air inlet control valve120, to allow pressure to build in the system.

As will be apparent to those skilled in the art, a number of modifications could be made to the preferred embodiments which would not depart from the spirit or the scope of the present invention. While the presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those skilled in the art. Insofar as these changes and modifications are within the purview of the appended claims, they are to be considered as part of the present invention.