Wheel end assembly high-temperature warning system

BACKGROUND OF THE PRESENT INVENTION

0001The present invention is directed to a wheel end assembly having a high temperature warning system for giving a warning in the event that the temperature in the assembly reaches a predetermined value such as by a hub-bearing failure or brake related failure. The system may be a stand-along system for installation on any vehicle such as a tractor trailer or in another embodiment may be a system combined with an automatic tire inflation system.

0002In the event of a wheel end assembly bearing failure or brake related failure on a vehicle such as a tractor trailer, the temperature in the assembly and axle spindle area can reach a temperature to where the tires or lubricant may ignite causing the vehicle to bum or the wheel to lock up. It is also the possibility, due to the intense heat caused by any failure that the wheel can detach from the axle. <patcit id="pcit0001" dnum="WO9840230A1"><text>WO 98/40230 A1</text></patcit> discloses an apparatus to provide a monitoring device for detecting problems associated with the wheels of trucks and trailers. The apparatus comprises one or more individual axle spindle sensors, a programmable microprocessor for receiving and processing the sensor signals to detect an alarm condition and alarm means to alert the driver of a problem with one or more of the wheels. <patcit id="pcit0002" dnum="US3645479A"><text>US 3 645 479 A</text></patcit> discloses an aircraft tire explosion prevention system comprising an aircraft tire, a temperature sensing valve connected with the aircraft tire, an aircraft wheel well containing the aircraft tire and retractable landing gear connected with the aircraft tire and wheel well. The temperature sensing valve on the aircraft tire releases the air pressure in the tire and activates a warning device when a predetermined temperature level is sensed.

BRIEF SUMMARY OF THE INVENTION

0003According to a first aspect of the present invention there is provided the high temperature warning system of claim 1. Additional aspects of the system are set out in dependent claims 2-6. According to a second aspect of the present invention there is provided the high temperature warning system of claim 7. According to a third aspect of the present invention there is provided the high temperature warning system of claim 8. Additional features and advantages of the invention will be described hereinafter. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. The novel features which are believed to be characteristic of the invention both as to its organization and method of operation, together with advantages, will be better understood from the following descriptions when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purposes of illustration and description only and is not intended as a definition of the limits of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

0004For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

0005<figref idref="f0001">FIG. 1</figref> is a schematic perspective elevational view, partly in cross section, illustrating one form of an axle of a vehicle having a high temperature warning system connected to the wheel assemblies;

0006<figref idref="f0002">FIG. 2</figref> is an enlarged elevational view, in cross section, taken along the line 2-2 of <figref idref="f0001">FIG. 1</figref> illustrating a wheel assembly and a high temperature warning system;

0007<figref idref="f0003">FIG. 3</figref> is a view similar to <figref idref="f0002">FIG. 2</figref> illustrating another form of the present invention;

0008<figref idref="f0004">FIG. 4</figref> is a view similar to <figref idref="f0002">FIG. 2</figref> illustrating still another embodiment of the present invention;

0009<figref idref="f0005">FIG. 5</figref> is a view similar to <figref idref="f0002">FIG. 2</figref> illustrating still another form of the present invention;

0010<figref idref="f0006">FIG. 6</figref> is an elevational cross-sectional view of a portion of an automatic tire inflation system connected to an axle and providing a high temperature warning system;

0011<figref idref="f0006">FIG. 7</figref> is an elevational view, in cross section; illustrating a partial of an automatic tire inflation system with other forms of high temperature warning systems;

0012<figref idref="f0007">FIG. 8</figref> is an elevational view in cross section of a part of an automatic tire inflation system showing another form of a temperature warning system; .

0013<figref idref="f0008">FIG. 9</figref> is an elevational view, in cross section, showing a part of another automatic tire inflation system having another form of a high temperature warning system.

DETAILED DESCRIPTION OF THE INVENTION

0014Referring now to <figref idref="f0001">FIGS. 1</figref> and <figref idref="f0002">2</figref>, the reference numeral 10 generally indicates the high temperature warning system of the present invention as installed in a vehicle having an axle 12 and a spindle 13 portion thereof. A wheel assembly 11 includes a hub 14 which rotates on inner and outer bearings 16 and 18, respectively, which rotate on inner and outer bearing races, respectively, 20 and 22, and extends through a brake drum 24 and supports a tire and wheel 26. As has been indicated in the event of a bearing 16 or 18 or a brake 24 failure, the temperature in the bearings 16 and 18, the brake drum 24 and spindle 13 area may reach a temperature to where the tires (not shown) on the tire and wheel 26 or lubricant (not shown) may ignite causing a fire. There is also the possibility because of the intense heat caused by such failures that the hub 14 and wheel and tire 26 may detach from the axle 12.

0015The temperature warning system 10 of the present invention includes an air pressure supply 28 which is a normal component on a truck or vehicle for various purposes such as brakes, a pressure protection valve 30, a flow switch 32 and an indicator or warning system light 34. The air pressure supply preferably includes the axle 12 which is hollow and is connected to supply 28 through line 36 and includes an internal plug 37 at each end of the axle 12 whereby the interior of the axle 12 forms part of the air pressure supply.

0016One or more normally closed valves, such as heat sensitive pressure barriers comprising a fusible plug 38 and 40, are connected between the inside 42 and the outside 44 of the pressure supply. The heat sensitive pressure barriers are fusible plugs 38 and 40 which also form a heat sensitive control for actuating the opening and closing of the valves or barriers 38 and 40 upon a predetermined temperature. The fusible plugs 38 and 40 include an eutectic alloy, which melts sharply at a predetermined temperature. Thus, when the area in which the plugs 38 and 40 are installed reach a certain temperatures the alloy will melt, creating an air leak from the air supply tank 28. This will be detected by the flow switch 32 which actuates the warning system light 34 which is positioned adjacent the driver of the vehicle to indicate a problem. The plugs 38 and 40 are mounted adjacent to the wheel assemblies 11 for measuring the temperature of the wheel assembly 11. In the embodiment shown in <figref idref="f0002">FIG. 2</figref> the plugs 38 and 40 extend radially outwardly from the axle 12 and spindle 13 and are positioned adjacent the bearings 20, 22 and brake drum 24. While any type of fusible plug is satisfactory, one sold under the trademark LEEKPRUF sold by the Mueller Refrigeration Company, Inc. is satisfactory. Of course, other types of thermally operated valves may be used for opening the air supply such as a thermally electric switch which operates an electric operated valve. And while it is convenient to use the hollow axle 12 as part of the air supply, other types of air supply tubing could be provided.

0017Referring now to <figref idref="f0003">FIG. 3</figref>, another form of the present invention is shown which is similar to <figref idref="f0002">FIG. 2</figref> with the exception that a heat sensitive pressure barrier or fusible plug 38a is positioned in the end plug 37. This provides a simplified manufacturing and construction form, but yet the heat sensitive pressure barrier and control is mounted sufficiently close to the heat assembly 13 for measuring the temperature of the wheel hub assemblies 11.

0018Referring now to <figref idref="f0004">FIG. 4</figref>, still another form of the present invention is shown in which, instead of the interior 42 of the axle 12 forming a part of the air pressure system air supply conduits or tubings 46 and 48 connected between the air line 36 (<figref idref="f0001">FIG. 1</figref>) and the fusible plugs 38 and 40, respectively.

0019Referring now to <figref idref="f0005">FIG. 5</figref>, another form is shown in which again the axle 12 does not form an air supply but an air conduit or tubing 50 is connected between the air line 36 (<figref idref="f0001">FIG. 1</figref>) and a fusible plug 38b in the end plug 37. The end plugs 37 in the embodiments of <figref idref="f0004">FIGS. 4</figref> and <figref idref="f0005">5</figref> serve the purpose of preventing debris in the inside of the axle 12.

0020While the warning system of <figref idref="f0001 f0002 f0003 f0004 f0005">FIGS. 1-5</figref> provide a stand alone system for vehicles such as trailer tractors, the warning system is particularly and easily adapted for use with an automatic tire inflation system which already includes an air pressure supply and a warning system measuring the loss of air pressure from the system or tires. Therefore, the combination of the temperature warning system of the present invention with an automatic tire inflation system provides a means of informing the vehicle operator of temperature problems. While the present invention can be used with various types of automatic tire inflation systems, it is useful with the system shown in <figref idref="f0006">FIG. 6</figref> and more fully described and illustrated in <patcit id="pcit0003" dnum="US20040000364A1"><text>US 2004/0000364 A1</text></patcit>. The reference numeral 100 generally indicates the rotary air connection for supplying air from an air supply on a vehicle in an automatic tire inflation system for a vehicle to the rotating tires. The numeral 112 generally indicates one axle or spindle, a hub cap 114 is provided at each end of the axle 112 for retaining lubricant in the wheel bearings and an air supply 116, either directly in the axle 112, or through an interior conduit (not shown) in the inside of the axle 112 supplies air to the rotary air connection through the inside of the axle. A pneumatic rotary union generally indicated by the reference 120 is supported and positioned in the center end of the axle 120, such as by force fit plug 220, but sealingly engages the interior of the axle 112 by a seal 124 if air is injected directly into the inside of the axle 112. The rotary union 120 has a first stationary part 128 having a passageway 136 therethrough. The passageway 136 is in communication with the air supply 116. A first resilient rotary seal 138 is supported in the passageway 136 and encircles the passageway 136. The union 120 includes a second rotatable part including a tubular member 142 having a first end 144 and a second end 146. The second end 146 is coaxially extendable through and is longitudinally and rotationally movable in the passageway 136 and sealably engages the rotary seal 138 and is in communication with the air supply 116. The first end 144 of the tubular member 142 is sealably connected to the air connection or T-body 152 on the hub cap 144 through a seal 150. An air connection 152 or T-body is provided on the hub cap 144 for connection to the tire or tires at the end of the axle 112. The end 144 of the tubular member 142 includes a shoulder which includes a bearing 101. In operation, air 116 is supplied through the stationary part 128 of the rotary union 120. The hub cap 114 rotates with the wheels relative to the tubular member 142. The above-named description is generally disclosed in the abovementioned <patcit id="pcit0004" dnum="US20040000364A1"><text>US 2004/0000364 A1</text></patcit>.

0021Thus, the automatic tire inflation system 100 of <figref idref="f0006">FIG. 6</figref> already includes an air pressure supply 116 and any suitable warning system consisting of a flow switch 32a and a warning indicator light 34a. The use of a heat sensitive pressure barrier 38c at a location near the wheel bearings or brake area on the spindle 113 provides a temperature warning system of the present invention. Again, if the spindle reaches a predetermined temperature the fusible plug melts releasing air from the air supply 116 and actuates the warning system light 34a for notification of the operator. The operator can quickly determine whether the warning system 34a is indicating a pressure leak in the tires or a high temperature problem in the wheel hub area.

0022Referring now to <figref idref="f0006">FIG. 7</figref>, another form of the present invention is shown having an automatic tire inflation system of which only stationary part 128 of the rotary connection is shown. In this form of the invention the air supply 116 is supplied through an internal conduit or tubing 150 which supplies air to the passageway 136 in the member 128 and also supplies air to a heat sensitive pressure barrier or fusible plug 38d.

0023Referring now to <figref idref="f0007">FIG. 8</figref>, a further form of the present invention is shown including an automatic tire inflation system in which only the stationary part 128 of the rotary connection is shown. Again, in this embodiment, the air supply 116 is supplied to an air tubing or conduit 150a inside of the axle 112 and is connected to the passageway 136 in the part 128. Heat sensitive pressure barriers or fusible plugs 38e and 40e are provided radially extending out of the axle 112 and are connected to the air supply tubing 150a by air tubes 152 and 154.

0024Referring now to <figref idref="f0008">FIG. 9</figref>, again, another form of the present invention is shown which includes an automatic tire inflation system in which only the stationary part 128 of the rotary connection is shown. In this embodiment, the interior of the hollow axle 112 forms part of the air supply for supplying air by 116 to the passageway 136. Again, heat sensitive pressure barriers or plugs 38f and 40f are provided radially extending through the wall of the axle 112 or spindle.

0025Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition, or matter, means, methods and steps described in the specification. As one will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods or steps.