INFLATE/DEFLATE TIRE SYSTEM

BACKGROUND

Certain vehicles in the mining, logging and off road industries are equipped with very large tires. Tire diameters for these vehicles can be in excess of 5 feet and can exceed 10 feet. Such large tires are needed to support the high weight of the vehicle and to provide sufficient ground clearance, among other reasons. Their size also makes these tires very expensive, often running in the tens of thousands of dollars apiece. Their size also makes them difficult to transport and they require special equipment to install on a vehicle. In addition, these tires are not readily available in the marketplace.

As a result of the above-mentioned issues associated with these tires owner/operators of these vehicles try to take a great deal of care of the tires. The care involves ensuring that the tires are at their optimum pressure for the task at hand so that the tires do not prematurely wear. This can be difficult, however, as the operating conditions can vary widely. When a tire is not at its optimum pressure, even for a short amount of time, the tire can experience wear because of the high weight on the tire.

For example, the load on a tire of a working vehicle, such as a dump truck, can vary widely depending on whether the truck is loaded or not. A tire set at a particular pressure for a particular load, such as for a fully loaded dump truck in the mining industry, can be quickly out an optimum pressure range when the vehicle is unloaded, even when the vehicle is partially unloaded.

Vehicle tire inflate/deflate systems are known but they cannot modify tire pressure during the relatively quick vehicle load and unload cycle. Instead, a single tire pressure has to be selected for all daily operations. Of course, as noted above, a single tire pressure is not optimized all the load conditions experienced by the vehicle during its operations, which results in premature wear.

Further, even when a single pressure is selected for the day, that pressure changes as a result of ambient temperature conditions. Thus, when a single pressure is selected in an attempt to optimize at least a portion of the vehicle operating conditions, that pressure often quickly changes during normal operation, making is less than optimal for the selected condition. In addition, the change in ambient temperatures can cause the tire to exceed its

recommended pressure, which results in premature wear.

As noted above, vehicle tire inflate/deflate systems are known. These systems often comprise a single Pneumatic Control Unit (PCU) for the entire vehicle. As a result, they require additional valves, solenoids and/or other devices to mechanically interrupt air flow in the lines between the PCU and the individual wheel ends. These additional mechanical devices add to the complexity, cost and unreliability of the prior art systems. In addition, they cannot inflate/deflate individual tires, such as simultaneously, at a rapid pace desired at loading/unloading locations, making them disadvantageous.

In view of the above-mentioned problems associated with trying to maintain the tires of a working vehicle at an optimum pressure, it would be advantageous to have a system that can operate in a large pressure range to quickly inflate and deflate multiple tires on a working vehicle to their optimum pressure. SUMMARY

A vehicle tire inflate/deflate system has a air supply tank containing a volume of pressurized air. A regulator is in fluid communication with the air supply tank to regulate the pressurized air. An air line is directly connected on one end to the regulator and on a second end to a wheel end. The air line extends without interruption by a mechanical air interrupting device to the wheel end. A pneumatic control unit is located at the wheel end of the vehicle. The pneumatic control unit has a non-rotating stationary portion, a rotating portion, and a rotary joint located between the stationary portion and the rotating portion to pass pressurized air between them, and at least one solenoid. BRIEF DESCRIPTION OF THE DRAWINGS The above, as well as other advantages, will become readily apparent to those skilled in the art from the following detailed description when considered in the light of the accompanying drawings in which:

Fig. 1 is a schematic plan view of a tire inflate/deflate system for one vehicle type;

Fig. 2 is a schematic of one embodiment of the tire inflate/deflate system of Fig. 1 ; and

Fig. 3 is a schematic detail of a feature of Fig. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood that the system and method described herein may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the concepts defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting.

Turning now to Fig. 2, a schematic of one embodiment of a tire inflate/deflate system 10 is depicted. The system 10 comprises a source for compressed air, such as a compressor 2. The compressor 12 may be mounted on the vehicle, as shown in Fig. 1. While Fig. 2 depicts one

compressor, there may be more than one compressor 12 on the vehicle that is part of the system 10. Regardless of the number of compressors, it is

preferable that the source for compressed air be capable of generating several thousand psi of air. Jn the depicted embodiment, a compressor 12 may be rated at 5000 psi and 10 cfm. It can be appreciated that this psi and cfm may work for one vehicle, but another vehicle may need a different psi and cfm. In that case, the appropriate compressor(s) can be selected.

The compressor 12 is connected to, such as in fluid communication with, at least one supply tank 14, such as through one or more fluid lines 3. In the depicted embodiment, a single supply tank 14 is depicted. However, it is permissible to include more than one supply tank as needed. Regardless of the number of supply tanks, at least one supply tank is preferably connected to, such as in fluid communication with, each wheel end 16.

As used herein, the term wheel end is limited to, for a steer axle, the knuckle and its associated non-rotatable spindle, the wheel hub(s) mounted for rotation on the spindle, and the tire(s) mounted on the wheel hub(s). For driven axles, the term wheel end is limited to the end portion of the driven axle opposite the differential, the wheel flange (or other device for connecting the axle to the wheel hub), the wheel hub(s) mounted to the wheel flange and the tire(s) mounted on the wheel hub(s).

The supply tank 14 holds the pressurized air generated by the

compressor 12. Typically, the supply tank 14 holds the pressurized air at the pressurization level provided by the compressor 12, but variations are permissible.

The tank 14 it may hold between approximately 200-5000 psi and it may take approximately 12 minutes to charge. Preferably, the tank can deliver approximately 1200-1500 cubic feet of air per minute at approximately 190 psi in 5 minutes or less to the tires. These exemplary tank performance numbers are based on one embodiment to which the invention is not limited.

As shown in Fig. 1 , the supply tank 14 is preferably mounted on the vehicle 17. The supply tank 14 may be proximate the compressor 12, but they may also be remote from one another.

As shown in Figs. 1 and 2, a regulator valve 18 is preferably connected to the supply tank 14. The regulator valve 18 is designed to regulate the pressure from the tank 14 down to a more traditional tire pressure, which for the exemplary tires described herein may be such as approximately 190 psi.

Fig. 2 depicts one embodiment where the regulator valve 18 is physically attached to the supply tank 14, such as at an end of the supply tank 14. The regulator valve 18 may be attached to other parts of the supply tank 14 or it may be physically separated from the tank but in fluid communication with the tank through one or more fluid lines.

A vent 20 may be associated with the regulator valve 18. The vent 20 is designed to exhaust pressurized air out of the supply tank 14 if the supply tank 14 pressure exceeds a predetermined amount. The vent 20 functions as a relief valve so that the tank 14 is not damaged by excess air pressure.

Fig. 2 depicts the embodiment where the vent 20 is physically attached to the valve 18. The vent may be separated from the valve 18 and in fluid communication with the valve 18 such as through one or more fluid lines.

At least one air line 22 extends from the regulator valve 18. In the depicted embodiment, an air line 22 extends from the regulator valve 18 to each wheel end 16. Fig. 2 shows one embodiment where one air line 22 extends to one wheel end, which is representative of each wheel end.

The air line 22 extends from the tank 14/regulator valve 18 directly to the wheel end 16. Preferably, the line 22 is not interrupted by valves, solenoids or other mechanical devices interrupting the flow of air along its length. This provides a single, dedicated, direct connection without interruption by mechanical devices from the tank 14/regulator valve 8 to the wheel end 16.

Fig. 1 schematically depicts one type of vehicle that may employ the system 10. As shown in the Figure, individual air lines 22A-D extends from the regulator valve 18 to each wheel end 16A-D. While Fig. 1 depicts a vehicle with 4 wheel ends 16A-D and a single tire 32A-D on each wheel end, the system 10 may be used with vehicles that have a lesser or greater number of wheel ends and/or tires. For example, it is common for the vehicle 7 to have two wheels/tires on the front, steerable axle (which may also be driven) and at least two, if not four, wheels/tires (two on each side) on the rear drive axle, which may also be steerable. It is also permissible for each wheel end 16 to have a dedicated compressor 12, supply tank 14 and regulator valve 18.

Each air line 22 must be capable of transmitting the pressurized air from the regulator valve 18 to the associated wheel end 16. Typically, these air lines 22 are robust and relatively large hoses designed to hold not only the air pressure, but also operate in a relatively harsh outdoor working environment.

The air lines 22 are often constructed of relatively thick and heavy materials for the above-mentioned reasons. The air lines 22 are provided sufficient length so that movement of the wheel end 16 can be accommodated through slack in the air lines 22. The construction and length of the air lines 22 provides them with a weight that will be utilized as described below. The connection of one wheel end 16 to the air line 22, regulator valve 18, supply tank 14 and compressor 12, and the subsequent operation of the system 10, will be discussed herein but it can be equally applied to each of the wheel ends 16.

As shown in Figs. 2 and 3, the air line 22 extends to a rotary joint 24 at the wheel end 16. More particularly, the air line 22 extends and connects with a stationary portion 26 of the rotary joint 24. The rotary joint 24 is comprised of the stationary portion 26 and a rotating portion 28. At least one rotary seal 29 seals the connection between the rotating portion 28 and the stationary portion 26.

The stationary portion 26 maybe made stationary by the connection with the air line 22. More particularly, the weight of the air line 22 fixes the stationary portion 26 in place and prevents it from rotating. In other words, the weight of the air line 22 is such that any rotation of the stationary portion 26 is defused, absorbed and/or prevented by its connection with the stationary connection of the low inertia/high weight of the air line 22. The stationary portion may also be fixed by being fastened to a portion of the vehicle chassis.

The above refers to the weight of the air line 22 to prevent the stationary portion 26 from rotating. The stationary portion 26 may also be prevented from rotating by any electrical connections to the stationary portion 26. The electrical connections may be such as wires and/or electrical conduits. The weight, and/or just the connections themselves, may be sufficient to reduce and/or prevent rotation of the stationary portion 26.

The rotating portion 28 resides on a rotating hub 30. The rotating portion 28 may be attached to the hub 30 such as through a bracket. The hub 30 is rotated via its connection to an axle (not shown). The axle has an outboard portion, ta which the hub 30 is connected, and an inboard portion. The inboard portion is connected to a source for rotation, such as, but not limited to, a differential. The hub 30 may comprise a wheel hub on which one or more tires 32 are mounted.

The two members 26, 28 of the rotary joint 24 cooperate to pass the pressurized air between the upstream stationary portion 26 and the

downstream rotating portion 28 without letting the pressurized air escape. A Pneumatic Control Unit (PCU) 34 is located at a wheel end 16 as defined herein. The PCU 34 comprises the stationary portion 26, the rotating portion 28, one or more solenoids, at least one pressure sensor/transducer and rotary seals 29. The rotary seals, the same noted above, operate to seal the rotary portion 28 and the stationary portion 26 from air escaping, and from dirt and debris entering the system 10.

Fig. 3 depicts a PCU 34 with a first solenoid 35A and a second solenoid 35B. While two solenoids are depicted, a greater number or a lesser number can be accommodated. Further, while Fig. 3 depicts the two solenoids in a particular orientation, other orientations are permissible.

The solenoids function like on/off switches to the flow of air. As shown in Fig. 3, the first solenoid 35A is in fluid communication with the pressurized air as it enters the PCU 34 across the rotary joint 24. If the first solenoid 35A is open, it will allow pressurized air to flow into a tire 32 associated with the PCU 34. If the first solenoid 35A is closed, the flow of pressurized air is blocked to the tire 32.

The second solenoid 35B permits or prevents the flow of pressurized air out of the tire 32. The second solenoid 35B is opened to let pressurized air from the tire escape and closed when air is not to escape.

As noted above, at least one pressure sensor/transducer is provided in the PCU 34. The pressure sensors/transducer(s) measure the pressure and create an electronic signal that communicates the sensed pressure to an electronic control unit 36, described in more detail below.

Exemplary locations for the pressure sensors/transducers are

schematically depicted in Fig. 3. As shown in Fig. 3, a pressure

sensor/transducer 37A may be located in an air inlet to the first solenoid 35A to sense the Inlet pressure. A pressure sensor/transducer 37B may be located in an air outlet to the first solenoid 35A to sense the outlet pressure going to the tire 32. Similarly, a pressure sensor/transducer 37C may be located in an air inlet to the second solenoid 35B to sense the inlet pressure coming from the tire 32. A pressure sensor/transducer 37D may be located in an air outlet to the second solenoid 35B to sense the outlet pressure. The air outlet for the second solenoid 35B is located at the wheel end 16, which permits air from the tire 32 to be exhausted at the wheel end 16. This arrangement assists in rapid deflation of the tire 32 as the tire air is quickly exhausted after leaving the tire 32 and does not need to travel through other conduits, etc.

Based on the foregoing, and from Fig. 2, it can be appreciated that the solenoids 35A, B are located on the rotating portion of the PCU 34.

In addition, at least one pressure sensor/transducer 37E may be located in each of the tires 32 to provide a tire pressure measurement.

As shown in Fig. 2, an Electronic Control Unit (ECU) 36 is provided on the vehicle. The ECU 36 is in communication, such as through telemetry or hardwires, to at least the regulator valve 18, the PCU 34, the associated sensors 37A-E and the tire pressure sensor for each tire/wheel. The ECU 36 signals the regulator valve 8 to open when pressurized air is required and signals the regulator valve 18 to close when pressurized air is no longer required. The ECU 36 also opens and closes the solenoid valves 35A, 35B in the PCU 34 to correspond with the opening and closing of the regulator valve 18.

Of course, the ECU may also receive signals from the valve 18, the PCU 34, the sensors 37A-E and any vehicle load sensors. By way of example only, the ECU may receive signals from the solenoids 35A, 35B. The solenoids35A, 35B may provide signals to the ECU regarding their state of operation, which may include trouble codes and/or faults.

The ECU 36 may utilize J1939/CAN bus connectivity and message interpretation. The ECU 36 may be capable of determining whether the air lines 22 are damaged or are leaking. The ECU 36 may also be capable of self- diagnostics of all integrated system components and data logging. In addition, the ECU 36 may be capable of communication regarding the status of the system 10 to a selected operator control panel. Further, the ECU 36 may be capable of automatic vehicle load sensing and/or receive operator input regarding the vehicle load so as to permit selective inflate/deflate of the tires 32. Fig. 2 schematically depicts a vehicle load sensor 39 in communication with the ECU 36.

One method of operating the system 10 comprises filling the supply tank 14 with pressurized air from the compressor 12. This may be done, for example, at vehicle start up so that the supply tank 14 has pressure available right away. If the pressure is not immediately needed, the pressure can be stored in the tank 14.

When it is determined that air is needed in a tire 32, such as to support a load being added to the vehicle, the ECU 36 signals the regulator valve 18 to open. The determination may be made by the vehicle operator and/or the vehicle, such as through vehicle load sensors and/or the tire pressure sensors 37E. The regulator valve 18 regulates the air in the supply tank 14 to a predetermined psi and the regulated air flows through the air line 22 to the stationary portion 26 of the rotary joint 24. The air flows through the stationary portion 26 to the rotating portion 28 across the rotary seal(s) 29. The first solenoid 35A opens to let the regulated air flow into the tire 32. When the pressure sensor 37E in the tire indicates the tire pressure has reached a desired level, the sensor signals the ECU 36, which then signals the regulator valve 18 to close. The first solenoid 35A also closes.

-When it is determined that air is to be removed from the tire 32, the ECU 36 signals the PCU 34 to open up the second solenoid 35B. The determination may be made by the vehicle operator and/or the vehicle, such as through vehicle load sensors and/or the tire pressure sensors. Air flows from the tire 32, through the second solenoid 35B, directly to the atmosphere, where it is vented. The air is released from the tire 32 until the tire pressure sensor 37E determines the desired pressure has been reached. When the desired pressure has been reached, the tire sensor 37E signals the ECU 36 which signals the second solenoid 35B to close.

The above-described inflate/deflate method can be used repeatedly.

For example, when a working vehicle needs extra tire pressure, such as to carry a load, air can be quickly added to the tires 32 with the onboard, and available, pressurized air in the supply tank 14. The amount of air added is based on the vehicle load and an optimized tire pressure for that load. When the load has been removed from the vehicle, air can be exhausted from the tires 32. Here again, the amount of air exhausted is based on the vehicle load and an optimized tire pressure for that load. When another load is to be carried* air can be added again through the above-described system 10. The system 10 is designed to accommodate repeated relatively rapid tire inflation and rapid tire deflation to achieve an optimized tire pressure for environmental and/or load conditions. The inflation and deflation steps can comprise minutes or even just seconds, depending on the amount of air added or evacuated from a tire 32.

By way of example only, one inflate/deflate routine for a vehicle working in a predetermined pattern, may be such as follows. First, the vehicle takes 2-5 minutes to inflate the tires at a vehicle loading area, where a cargo load is added to the vehicle. The inflate step may be done while the vehicle is simultaneously being loaded, about to be loaded, and/or after loading is complete. The load time depends on the quantity and type of material being loaded.

The vehicle then maintains the tire pressure in the vehicle loaded condition for the time it takes the vehicle to travel to the unloading area. The time it takes the vehicle to travel to the unloading area can vary based on distance, vehicle speed, obstacles, required stops or slow downs, etc. In this non-limiting example, the travel time may be approximately 5 minutes.

When the vehicle reaches the unloading area, at least a portion of the cargo load is removed from the vehicle. The time it takes to unload the vehicle varies based on the quantity and type of material being removed from the vehicle. The tires may be deflated during the unloading process, before the unloading process and/or after the unloading process. Preferably, the deflate step may take 2-5 minutes.

The vehicle may be loaded at the unload station, or it may return to the original load station, to repeat the cycle and the above-mentioned inflate/deflate process.

It is preferred that the tires 32 be adjusted to their optimum pressure entirely, or at least mostly, during a loading or unloading operation so that the vehicle operator does not have to wait until after the loading or unloading is complete to move the vehicle. The pressure in each tire 32 can be adjusted to an optimum for its location on each vehicle and the load currently on the tire 32. Thus, the tire 32 pressure is optimized for all conditions which leads to increased tire 32 and vehicle performance and increased tire 32 life. In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.