Steering axle assembly with self-lubricated bearings

1. A steering axle assembly for a heavy duty truck, the steering axle assembly comprising:

a wheel end having a knuckle section comprising a first arm and a second arm each extending from the knuckle section, the first arm having a first interior surface defining a first bore extending between a first exterior axial end surface and a first interior axial end surface, and the second arm having a second interior surface defining a second bore extending between a second exterior axial end surface and a second interior axial end surface;

an axle beam having a connecting end, the connecting end having a third interior surface defining a third bore extending between a third axial end surface and a fourth axial end surface;

a pin having a cylindrical exterior surface, the pin being disposed in and coaxial with the first bore, the second bore and the third bore;

a self-lubricated bearing system including a first tubular bushing, a second tubular busing and an annular thrust bearing;

the first tubular bushing being positioned in the first bore and engaging the first interior surface and a portion of the cylindrical exterior surface of the pin;

the second tubular bushing being positioned in the second bore and engaging the second interior surface and a portion of the cylindrical exterior surface of the pin;

the annular thrust bearing assembly being disposed between the first interior axial end surface and the third axial end surface, the annular thrust bearing assembly having a first plate in rotational communication with a second plate; and

the self-lubricated bearing system having an adequate amount of lubricant therein at a beginning of life state and the amount of the lubricant being sufficient for an end of life state defined by at least one million miles of operation of the heavy duty truck, without replenishment of the lubricant.

2. The steering assembly of claim 1 , wherein the annular thrust bearing assembly includes a thrust bearing disposed between and slidingly engaging the first plate and the second plate; and

at least one of the first tubular bushing, the second tubular bushing and the thrust bearing are manufactured from a self-lubricated material.

3. The steering assembly of claim 2 , wherein the lubricant in the self-lubricated material is polytetrafluoroethylene.

4. The steering assembly of claim 2 , wherein the self-lubricated material is one of a homogenous entity and a homogeneous molded liner.

5. The steering assembly of claim 2 , wherein the self-lubricated material is a woven fabric.

6. The steering assembly of claim 2 , wherein the self-lubricated material has a dynamic capacity of at least 38,000 pounds per square inch.

7. The steering assembly of claim 2 , wherein at least one of the self-lubricated thrust bearing, the first tubular bushing and the second tubular bushing wear less than ⅔ from the beginning of life state to the end of life state.

8. The steering assembly of claim 2 , wherein at least one of the self-lubricated thrust bearing, the first bushing and the second bushing wear less than 0.010 inches from the beginning of life state to the end of life state.

9. The steering assembly of claim 1 , wherein the annular thrust bearing assembly consists of a sealed thrust bearing assembly having a plurality of rolling elements disposed between and rollingly engaging the first plate and the second plate.

10. The steering axle assembly of claim 9 , wherein the rolling elements are tapered needle bearings.

11. The steering axle assembly of claim 9 , wherein the rolling elements are manufactured from a metallic material.