Steer axle tire inflation system

1. A method of providing a tire inflation system for a steer-axle wheel end assembly having a tire and a steer-axle spindle pivotably mounted to a steer axle, the steer-axle spindle having an inner face facing the steer axle and having an outer end, the method comprising:

forming an axial channel along the central axis of the steer-axle spindle, the axial channel extending from the outer end toward the inner face;

directly disposing a first seal circumferentially in the axial channel, the first seal being an annular seal;

mounting a rotary union to said wheel end assembly at the at the outer end of the steer-axle spindle, the rotary union being in sealed for fluid communication with a pressurized fluid supply and with the tire, the rotary union comprising:

a rotary body being configured to mount to the exterior or interior of a hubcap, or comprising part of a hubcap;

a second seal disposed in the rotary body; and

a tubular member sealingly disposed between the first seal and the second seal;

providing sealed fluid communication from the rotary union to a pressurized fluid supply through the axial channel; and

providing sealed fluid communication from the rotary union to the tire.

2. The method of claim 1 , wherein the axial channel is formed by drilling.

3. The method of claim 1 , further comprising forming a radial channel extending radially from the axial channel through the spindle.

4. The method of claim 1 further comprising:

disposing a non-rotatable portion of the rotary union in sealed communication with the pressurized fluid supply; and

disposing a rotatable portion of the rotary union in sealed communication with the tire.

5. The method of claim 1 , wherein the tubular member is rotatably disposed in the annular seal.

6. The method of claim 1 , wherein the tubular member is translatably disposed in the annular seal.

7. The method of claim 1 , wherein the tubular member is rotatably disposed in either the first annular seal or in the second annular seal.

8. The method of claim 1 , wherein the tubular member is rotatably disposed in both the first annular seal and in the second annular seal.

9. The method of claim 1 , wherein the rotary union comprises a rotatable graphite portion and the tubular member comprises a steel portion, the rotatable graphite portion and the steel portion abutting to form a face seal; and the tubular member is non-rotatingly disposed in the first annular seal.

10. A method of preparing a steer-axle spindle for a tire inflation system, the steer-axle spindle having an inner face facing the steer axle and having an outer end, the method comprising:

forming an axial channel along the central axis of the steer-axle spindle, the axial channel extending from the outer end toward the inner face; and

forming a groove circumferentially in the axial channel, the groove being configured to receive an annular seal.

11. The method of claim 10 , wherein the axial channel is formed by drilling.

12. The method of claim 10 , further comprising forming a radial channel extending radially from the axial channel through the spindle.

13. The method of claim 10 , further comprising forming the axial channel from the outer end through the inner face.

14. The method of claim 13 , further comprising forming a radial channel extending radially from the axial channel through the spindle, and plugging the axial channel at the inner face.

15. A method of preparing a steer-axle spindle for a tire inflation system, the steer-axle spindle having an inner face facing the steer axle and having an outer end, the steer axle spindle having an axial channel along the central axis of the steer-axle spindle, the axial channel extending from the outer end toward the inner face, the method comprising forming a groove circumferentially in the axial channel, the groove being configured to receive an annular seal.

16. The method of claim 10 , the spindle further having a radial channel extending radially from the axial channel through the spindle.