Patent Description:
A tire inflation system having a passage for routing pressurized gas through a hub is disclosed in <CIT>. <CIT> discloses a wheel end assembly that has axially inner shaft sealing rings that extends from an axle body to a hub to define an annular chamber. <CIT> discloses a wheel end seal assembly <NUM> that extends from a spindle to a hub having a single hub passage. <CIT> discloses an air delivery apparatus that has two conduits that extends from an end of an axle shaft to different tires.

The invention solves the problem of enabling an improved flow of compressed air by providing the features as set out in claim <NUM>.

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms within the scope of the appended claims.

Referring to <FIG>, an example of a wheel end assembly <NUM> is shown. The wheel end assembly <NUM> may be provided with a vehicle like a truck, bus, farm equipment, mining equipment, military transport or weaponry vehicle, or cargo loading equipment for land, air, or marine vessels. The vehicle may include a trailer for transporting cargo in one or more embodiments.

As an overview, the wheel end assembly <NUM> may be associated with a tire inflation system that may help obtain and/or maintain a desired air pressure within one or more tires. The tire inflation system may be disposed on the vehicle and may be configured to provide a pressurized gas or pressurized gas mixture to one or more tires and exhaust the pressurized gas or pressurized gas mixture from one or more tires. For clarity, the term "pressurized gas" may refer to either a purified pressurized gas (e.g., nitrogen) or a pressurized gas mixture (e.g., air). For convenience in reference, the term "air" is used below as a generic designator that is not intended to be limiting to a particular pressurized gas (e.g., an "air passage" may facilitate the flow of a pressurized gas other than air). Tire inflation or deflation may be desired when the tire pressure is not sufficiently close to the tire pressure specified by the vehicle manufacturer and/or is inappropriate for the type of ground over which a vehicle is travelling. For instance, higher tire pressures may be desired when a vehicle is travelling on a paved road as compared to when a vehicle is travelling off-road.

The tire inflation system may be fluidly connected to a pressurized gas source <NUM>, which is best shown in <FIG>. The pressurized gas source <NUM> may be configured to supply or store a volume of a pressurized gas. For example, the pressurized gas source <NUM> may be a tank, a pump like a compressor, or combinations thereof. The pressurized gas source <NUM> may be configured to provide pressurized gas at a pressure that is greater than or equal to a desired inflation pressure of a tire. The pressurized gas source <NUM> may be disposed on the vehicle and may be fluidly connected to at least one tire via passages in various components.

Referring again to <FIG>, the wheel end assembly <NUM> may be configured to support a vehicle wheel and a brake assembly. The wheel end assembly <NUM> may be disposed on or may be mounted to a structural component <NUM> and may be provided in a steerable configuration or a non-steerable configuration. In a steerable configuration, the wheel end assembly <NUM> may be mounted to a steerable structural component, such as a steering knuckle. In a non-steerable configuration, the wheel end assembly <NUM> may be mounted to a non-steerable structural component, such as a non-rotatable knuckle or an axle housing of an axle assembly. In at least one configuration and as is best shown with reference to <FIG> and <FIG>, the wheel end assembly <NUM> may include a spindle <NUM>, a hub <NUM>, an inboard wheel bearing <NUM>, an outboard wheel bearing <NUM>, a hub seal <NUM>, and a rotary seal assembly <NUM>. Optionally, the wheel end assembly <NUM> may be associated with an axle shaft <NUM> and may include hub housing <NUM>, a brake drum <NUM>, and a gear reduction unit <NUM>, which is best shown in <FIG>.

Referring to <FIG> and <FIG>, the spindle <NUM> may extend along or around an axis <NUM> and may be configured to support components of the wheel end assembly <NUM>. The spindle <NUM> may be fixedly mounted to a structural component <NUM>, such as a steering knuckle or an axle housing as previously described. It is also contemplated that the spindle <NUM> may be integrally formed with the structural component <NUM> rather than being a separate part from the structural component <NUM>. In at least one configuration, the spindle <NUM> may include a mounting flange <NUM> and a tubular portion <NUM>. In addition, the spindle <NUM> may define a spindle air passage <NUM> and optionally a spindle hole <NUM>.

The mounting flange <NUM> may facilitate mounting of the spindle <NUM> to a structural component <NUM>. For instance, the structural component <NUM> may include a mounting ring <NUM> that may be integrally formed with the structural component <NUM> or may be provided as a separate part that is fixedly attached to structural component <NUM>. The mounting ring <NUM> may extend around the axis <NUM>, may be received inside a hole in the structural component <NUM>, and/or may have holes that facilitate mounting of the spindle <NUM>. As is best shown with in <FIG> and <FIG>, the mounting flange <NUM> may have an air passage hole <NUM>.

Referring to <FIG>, the air passage hole <NUM> may be a through hole that may extend through the mounting ring <NUM>. The air passage hole <NUM> may have a recess <NUM>. The recess <NUM> may have any suitable shape. For instance, the recess <NUM> may be generally D-shaped and may include a straight side <NUM> and a curved side <NUM> that extends along an arc or radius from one end of the straight side <NUM> to an opposite end of the straight side <NUM>.

A hollow tubular bushing <NUM> may extend through the air passage hole <NUM> and may facilitate mounting of a fitting <NUM> that may be fluidly connectable to the pressurized gas source <NUM>. The bushing <NUM> may have a shape that is compatible with the air passage hole <NUM>. For instance, the bushing <NUM> may have a bushing flange <NUM> that may be received in the recess <NUM> to help inhibit rotation of the bushing <NUM> with respect to the mounting ring <NUM>. In the configuration shown, the bushing flange <NUM> may have a D-shaped perimeter that may have a straight bushing flange side <NUM> and a curved bushing flange side <NUM> that extends along an arc or radius from one end of the straight bushing flange side <NUM> to an opposite end of the straight bushing flange side <NUM>. The straight bushing flange side <NUM> and a curved bushing flange side <NUM> may be aligned with the straight side <NUM> and a curved side <NUM>, respectively. It is also contemplated that the bushing <NUM> may be omitted and that the fitting <NUM> may be directed coupled to the mounting ring <NUM>.

Referring to <FIG> and <FIG>, the mounting flange <NUM> may be disposed at an inboard end of the spindle <NUM> that may be disposed adjacent to the structural component <NUM>. In at least one configuration, the mounting flange <NUM> may extend further away from the axis <NUM> than the tubular portion <NUM> and may extend radially outward from the tubular portion <NUM>. The mounting flange <NUM> may include a plurality of holes <NUM> that may receive fasteners <NUM>, such as bolts, that may couple the spindle <NUM> to the structural component <NUM>, such as to the mounting ring <NUM>. Alternatively, the holes <NUM> and fasteners <NUM> may be omitted and the spindle <NUM> may be coupled to the structural component <NUM> with a weld, by press fitting, or the like. The mounting flange <NUM> may be disposed at an end of the tubular portion <NUM>.

Referring primarily to <FIG>, the tubular portion <NUM> may extend from the mounting flange <NUM>. For instance, the tubular portion <NUM> may extend in an axial direction that may extend away from the mounting flange <NUM> in an outboard direction away from the structural component <NUM>. In at least one configuration, the tubular portion <NUM> may have a threaded portion <NUM>. The tubular portion <NUM> may include one or more outer surfaces, such as a first outer surface <NUM>, a second outer surface <NUM>, a third outer surface <NUM>, and a fourth outer surface <NUM>.

The threaded portion <NUM> may be axially positioned or positioned along the axis <NUM> between the distal end of the spindle <NUM> and the first outer surface <NUM>. The threaded portion <NUM> may face away from the axis <NUM> and may threadingly engage a preload nut <NUM>. For instance, the preload nut <NUM> may be threaded onto the threaded portion <NUM>, may inhibit axial movement of the outboard wheel bearing <NUM>, and may exert a preload force on the outboard wheel bearing <NUM>.

The first outer surface <NUM> may extend around the axis <NUM> and may face away from the axis <NUM>. The first outer surface <NUM> may be an outside circumference of a portion of the tubular portion <NUM>. The first outer surface <NUM> may be axially positioned between the threaded portion <NUM> and the second outer surface <NUM>. In addition, the first outer surface <NUM> may be positioned further from the axis <NUM> than the threaded portion <NUM>. The outboard wheel bearing <NUM> may be disposed on the first outer surface <NUM>.

The second outer surface <NUM> may extend around the axis <NUM> and may face away from the axis <NUM>. The second outer surface <NUM> may be an outside circumference of a portion of the tubular portion <NUM>. The second outer surface <NUM> may be axially positioned between the first outer surface <NUM> and the mounting flange <NUM>. For instance, the second outer surface <NUM> may be axially positioned between the first outer surface <NUM> and the third outer surface <NUM>. In addition, the second outer surface <NUM> may be disposed further from the axis <NUM> than the first outer surface <NUM> and may have a larger diameter than the first outer surface <NUM> to help inhibit axial movement of the inner race of the outboard wheel bearing <NUM> toward the mounting flange <NUM>. The rotary seal assembly <NUM> may be disposed on the second outer surface <NUM>. It is also contemplated that the second outer surface <NUM> may be omitted and the outboard wheel bearing <NUM> and the rotary seal assembly <NUM> may be disposed on a common surface, such as the first outer surface <NUM>.

The third outer surface <NUM> may extend around the axis <NUM> and may face away from the axis <NUM>. The third outer surface <NUM> may be an outside circumference of a portion of the tubular portion <NUM>. The third outer surface <NUM> may be axially positioned between the second outer surface <NUM> and the mounting flange <NUM>. For instance, the third outer surface <NUM> may be axially positioned between the second outer surface <NUM> and the fourth outer surface <NUM>. In addition, the third outer surface <NUM> may be disposed further from the axis <NUM> than the second outer surface <NUM> and may have a larger diameter than the second outer surface <NUM>. It is also contemplated that the third outer surface <NUM> may be omitted and the rotary seal assembly <NUM> may be disposed on a common surface, such as the first outer surface <NUM> or the second outer surface <NUM>. The inboard wheel bearing <NUM> may be disposed on the third outer surface <NUM>.

The fourth outer surface <NUM> may extend around the axis <NUM> and may face away from the axis <NUM>. The fourth outer surface <NUM> may be an outside circumference of a portion of the tubular portion <NUM>. The fourth outer surface <NUM> may be axially positioned between the third outer surface <NUM> and the mounting flange <NUM>. In at least one configuration, the fourth outer surface <NUM> may extend from the mounting flange <NUM>. The fourth outer surface <NUM> may be disposed further from the axis <NUM> than the third outer surface <NUM> and may have a larger diameter than the third outer surface <NUM> to help inhibit axial movement of the inner race of the inboard wheel bearing <NUM> toward the mounting flange <NUM>. The hub seal <NUM> may be disposed on the fourth outer surface <NUM>. It is contemplated that the fourth outer surface <NUM> may be omitted and that the hub seal <NUM> and the inboard wheel bearing <NUM> may be disposed on a common surface.

Referring to <FIG>, the spindle air passage <NUM> may help fluidly connect a pressurized gas source <NUM> to a tire <NUM> that may be mounted on a wheel <NUM>. The spindle air passage <NUM> may be spaced apart from the spindle hole <NUM>. In at least one configuration, the spindle air passage <NUM> may extend through the mounting flange <NUM> and the tubular portion <NUM> of the spindle <NUM>. As is best shown in <FIG>, the spindle air passage <NUM> may have a first port <NUM> and a second port <NUM>.

The first port <NUM> may be fluidly connectable to the pressurized gas source <NUM>. In at least one configuration, the first port <NUM> may be provided in the mounting flange <NUM>.

The second port <NUM> may be disposed at an opposite end of the spindle air passage <NUM> from the first port <NUM>. The second port <NUM> may be fluidly connected to an air passage in the hub <NUM> via the rotary seal assembly <NUM>. The second port <NUM> may be provided in the tubular portion <NUM>. For instance, the second port <NUM> may extend from an outer surface of the spindle <NUM>, such as the second outer surface <NUM>.

The mounting flange <NUM> and the tubular portion <NUM> may cooperate to define the spindle hole <NUM>. The spindle hole <NUM> may be a through hole that may extend along and may be centered about the axis <NUM>.

Referring to <FIG> and <FIG>, the hub <NUM> may be rotatable about the axis <NUM> with respect to the spindle <NUM>. In addition, the hub <NUM> may be configured to facilitate mounting of at least one wheel <NUM>. In a drive axle configuration, the hub <NUM> may be operatively connected to an axle shaft <NUM>. In at least one configuration, the hub <NUM> may include a hub cavity <NUM>, a hub mounting flange <NUM>, an annular hub chamber <NUM>, and at least one hub air passage <NUM>.

The hub cavity <NUM> may extend around the axis <NUM>. The hub cavity <NUM> may receive at least a portion of various components of the wheel end assembly <NUM>, such as the spindle <NUM>, the inboard wheel bearing <NUM>, the outboard wheel bearing <NUM>, the hub seal <NUM>, the rotary seal assembly <NUM>, and the gear reduction unit <NUM>. The hub cavity <NUM> may be at least partially defined by an inner side <NUM> that may face toward the spindle <NUM> and that may extend around the axis <NUM>.

The hub mounting flange <NUM> may facilitate mounting of at least one wheel <NUM>. For example, the hub mounting flange <NUM> may extend away from the axis <NUM> and may include a set of mounting fastener holes that may each receive a mounting lug bolt <NUM>. A mounting lug bolt <NUM> may extend through a corresponding hole in a wheel <NUM>. A lug nut <NUM> may be threaded onto a mounting lug bolt <NUM> to secure a wheel <NUM> to the hub <NUM>. In the configuration shown in <FIG> and <FIG>, two wheels <NUM> are illustrated that each support a corresponding tire <NUM>; however, it is contemplated that a single wheel <NUM> and tire <NUM> may be provided.

Referring primarily to <FIG> and <FIG>, the annular hub chamber <NUM> may fluidly connect the spindle air passage <NUM> to at least one hub air passage <NUM>. According to the invention, the annular hub chamber <NUM> extends around the axis <NUM>. The annular hub chamber <NUM> has a port <NUM> and may be at least partially defined by an arcuate wall <NUM>. Optionally, the annular hub chamber <NUM> may be further defined by a first connecting wall <NUM>, a second connecting wall <NUM>, or both.

Referring to <FIG>, the port <NUM> may be fluidly connected to the second port <NUM> of the spindle air passage <NUM>. For instance, the port <NUM> may be disposed proximate the rotary seal assembly <NUM>. According to the invention, the port <NUM> extends continuously around the axis <NUM>. The port <NUM> may or may not extend from the arcuate wall <NUM>. In at least one configuration, the port <NUM> may be at least partially defined by a first side wall <NUM> and a second side wall <NUM>.

The first side wall <NUM> and the second side wall <NUM> may be spaced apart from each other. The first side wall <NUM> and the second side wall <NUM> may extend from the inner side <NUM> of the hub <NUM> in a direction that extends away from the spindle <NUM>. In at least one configuration, first side wall <NUM> and the second side wall <NUM> may be disposed substantially perpendicular to the axis <NUM>. Substantially perpendicular may be within ±<NUM>° of perpendicular.

Referring to <FIG>, the arcuate wall <NUM> may face toward the axis <NUM> and may extend along an arc. At least a portion of the arcuate wall <NUM> may be disposed further from the axis <NUM> than the inboard wheel bearing <NUM>, the outboard wheel bearing <NUM>, or both.

Optionally, a first connecting wall <NUM> and a second connecting wall <NUM> may help define the annular hub chamber <NUM>. The first connecting wall <NUM> may extend from an end of the first side wall <NUM> to a first end of the arcuate wall <NUM>. The second connecting wall <NUM> may extend from an end of the second side wall <NUM> to a second end of the arcuate wall <NUM> that may be disposed opposite the first end of the arcuate wall <NUM>. It is also contemplated that the first connecting wall <NUM>, the second connecting wall <NUM>, or both may be omitted. For instance, a first end of the arcuate wall <NUM> may extend from an end of the first side wall <NUM> when the first connecting wall <NUM> is omitted. Similarly the second end of the arcuate wall <NUM> may extend from an end of the second side wall <NUM> when the second connecting wall <NUM> is omitted.

At least one hub air passage <NUM> may be provided with the hub <NUM>. A hub air passage <NUM> may fluidly connect the annular hub chamber <NUM> to a tire <NUM>. The hub air passage <NUM> may be defined in the hub <NUM> and may extend through the hub <NUM>. In <FIG>, two hub air passages <NUM> are illustrated. For convenience in reference, the hub air passages <NUM> may be referred to as a first hub air passage and a second hub air passage. The first hub air passage and the second hub air passage may be disposed on opposite sides of the spindle <NUM>. The first and second hub air passages may be fluidly connected to a common tire <NUM> and wheel <NUM> or may be fluidly connected to different tires <NUM> and wheels <NUM> as will be discussed in more detail below. In at least one configuration, the first hub air passage may be disposed directly opposite the second hub air passage such that the first hub air passage and the second hub air passage may be coplanar. As is best shown in <FIG>, the hub air passage <NUM> may have a first port <NUM> and a second port <NUM>. The hub air passage <NUM> may also have a first segment <NUM>, a second segment <NUM>, and a third segment <NUM>.

The first port <NUM> may be fluidly connected to the annular hub chamber <NUM>. For instance, the first port <NUM> may extend from the arcuate wall <NUM>. The first port <NUM> may be axially positioned further from the distal end of the spindle <NUM> than the port <NUM> of the annular hub chamber <NUM> is positioned from the distal end of the spindle <NUM>.

The second port <NUM> may be disposed at an opposite end of the hub air passage <NUM> from the first port <NUM>. The second port <NUM> may be fluidly connectable to a wheel <NUM>, such as via a conduit as will be discussed in more detail below.

The first segment <NUM> may extend from the annular hub chamber <NUM>. For instance, the first segment <NUM> may include the first port <NUM> and may extend from the annular hub chamber <NUM> at an oblique angle with respect to the axis <NUM>.

The second segment <NUM> may fluidly connect the first segment <NUM> to the third segment <NUM>. For instance, the second segment <NUM> may extend from the first segment <NUM> in a direction that extends away from the axis <NUM>. In at least one configuration, the second segment <NUM> may be disposed substantially perpendicular to the axis <NUM>. Substantially perpendicular may be within ±<NUM>° of perpendicular.

The third segment <NUM> may extend from the second segment <NUM> to the second port <NUM>. In at least one configuration, the third segment <NUM> may extend substantially parallel to the axis <NUM>. Substantially perpendicular may be within ±<NUM>° of parallel.

Referring to <FIG> and <FIG>, the inboard wheel bearing <NUM> may be disposed on the spindle <NUM> and may rotatably support the hub <NUM>. The inboard wheel bearing <NUM> may have any suitable configuration. For instance, the inboard wheel bearing <NUM> may include a plurality of rolling elements, such as balls or rollers, that may be disposed between an inner race and an outer race. The inner race may extend around and may be disposed on a surface of the spindle <NUM>, such as the third outer surface <NUM>. As such, the inboard wheel bearing <NUM> may be axially positioned closer to the mounting flange <NUM> than the outboard wheel bearing <NUM>. The outer race may engage the hub <NUM> and may extend around the inner race.

The outboard wheel bearing <NUM> may be disposed on the spindle <NUM> and may rotatably support the hub <NUM>. The outboard wheel bearing <NUM> may have a similar configuration as the inboard wheel bearing <NUM>. For instance, the outboard wheel bearing <NUM> may include a plurality of rolling elements, such as balls or rollers, that may be disposed between an inner race and an outer race. The inner race may extend around and may be disposed on a surface of the spindle <NUM>, such as the first outer surface <NUM>. The outer race may engage the hub <NUM> and may extend around the inner race.

The hub seal <NUM> may extend from the spindle <NUM> to the hub <NUM>. For example, the hub seal <NUM> may extend from the fourth outer surface <NUM> of the spindle <NUM> in a direction that extends away from the axis <NUM> to the hub <NUM>. The hub seal <NUM> may be disposed near an inboard end of the hub <NUM> that may be disposed closest to the mounting flange <NUM> of the spindle <NUM>. The hub seal <NUM> may be axially positioned between the inboard wheel bearing <NUM> and the mounting flange <NUM>.

The rotary seal assembly <NUM> may fluidly connect the spindle air passage <NUM> to the hub air passage <NUM>. More specifically, the rotary seal assembly <NUM> may fluidly connect the second port <NUM> of the spindle air passage <NUM> to the port <NUM> of the hub air passage <NUM>. The rotary seal assembly <NUM> may extend from the spindle <NUM> to the hub <NUM>. For example, the rotary seal assembly <NUM> may extend from the second outer surface <NUM> of the spindle <NUM> in a direction that extends away from the axis <NUM> to the hub <NUM>. The rotary seal assembly <NUM> may be axially positioned between the inboard wheel bearing <NUM> and the outboard wheel bearing <NUM>. The rotary seal assembly <NUM> may seal against the spindle <NUM> and the hub <NUM> in a manner that permits the hub <NUM> to rotate with respect to the spindle <NUM>. As one example, the rotary seal assembly <NUM> may be fixedly disposed on the spindle <NUM> such that the rotary seal assembly <NUM> does not rotate with respect to the spindle <NUM> and the hub <NUM> may rotate with respect to the rotary seal assembly <NUM>. As another example, the rotary seal assembly <NUM> may be fixedly disposed on the hub <NUM> such that the hub <NUM> and the rotary seal assembly <NUM> may be rotatable with respect to the spindle <NUM>.

The rotary seal assembly <NUM> may have any suitable configuration. For instance, the rotary seal assembly <NUM> may extend continuously around the spindle <NUM> and may have an inboard sealing portion <NUM> and an outboard sealing portion <NUM>. The inboard sealing portion <NUM> may extend from the spindle <NUM> to the hub <NUM> and may be axially positioned between the inboard wheel bearing <NUM> and the second port <NUM> of the spindle air passage <NUM>. The outboard sealing portion <NUM> may extend from the spindle <NUM> to the hub <NUM> and may be axially positioned between the outboard wheel bearing <NUM> and the second port <NUM> of the spindle air passage <NUM>. As such, the spindle <NUM>, the hub <NUM>, the inboard sealing portion <NUM>, and the outboard sealing portion <NUM> may cooperate to define a chamber from which the second port <NUM> of the spindle air passage <NUM> and the port <NUM> of the annular hub chamber <NUM> may extend.

Referring to <FIG> and <FIG>, the hub housing <NUM> may be mounted to the hub <NUM>. For example, the hub housing <NUM> may be attached to an end of the hub <NUM> that faces away from the mounting flange <NUM> of the spindle <NUM>. The hub housing <NUM> may enclose an outboard end of the hub cavity <NUM>.

Referring to <FIG> and <FIG>, the axle shaft <NUM>, if provided, may provide torque to the wheel end assembly <NUM>. For instance, the axle shaft <NUM> may be operatively connected at a first end to a vehicle drivetrain component, such as a differential or vehicle power source, and may be coupled to or operatively connected to the wheel end assembly <NUM> at a second end. In at least one embodiment, the axle shaft <NUM> or a portion thereof may extend along the axis <NUM>. For example, the axle shaft <NUM> or a portion thereof may extend through the spindle hole <NUM> and may be operatively connected to the hub <NUM>, such as via the gear reduction unit <NUM> or without the gear reduction unit <NUM>. It is also contemplated that the axle shaft <NUM> may be configured for use with an independent suspension system and may have multiple shaft segments and/or joints that may facilitate relative movement between the first end and the wheel end assembly <NUM>.

The hub housing <NUM>, if provided, may be fixedly mounted to the hub <NUM>. As such, the hub housing <NUM> and the hub <NUM> may be rotatable together about the axis <NUM> with respect to the spindle <NUM>. The hub housing <NUM> may extend around and may at least partially receive the spindle <NUM>, the hub <NUM>, the outboard wheel bearing <NUM>, the rotary seal assembly <NUM>, the annular hub chamber <NUM>, or combinations thereof. The hub housing <NUM> may also receive the gear reduction unit <NUM>. In at least one configuration and as is best shown with reference to <FIG>, the hub housing <NUM> may include a hub housing flange <NUM> and at least one hub housing passage <NUM>.

The hub housing flange <NUM> may be disposed at an end of the hub housing <NUM> that may face toward the hub mounting flange <NUM>. The hub housing flange <NUM> may extend away from the axis <NUM> and may have a first flange side <NUM> and a second flange side <NUM>.

The first flange side <NUM> may face toward the hub mounting flange <NUM>. For example, the first flange side <NUM> may engage or contact the hub mounting flange <NUM>.

The second flange side <NUM> may be disposed opposite the first flange side <NUM>. The second flange side <NUM> may face toward and may engage or contact the brake drum <NUM>.

The hub housing passage <NUM> may be configured as a through hole that may extend from the first flange side <NUM> to the second flange side <NUM>. A different hub housing passage <NUM> may be associated with each hub air passage <NUM>. For instance, a hub housing passage <NUM> may be aligned with and may be fluidly connected to a corresponding hub air passage <NUM>.

Referring to <FIG> and <FIG>, the brake drum <NUM> may be fixedly mounted to the hub <NUM>. As such, the brake drum <NUM> and the hub <NUM> may be rotatable together about the axis <NUM> with respect to the spindle <NUM>. The brake drum <NUM> may extend around and may at least partially receive the spindle <NUM>, the hub <NUM>, the inboard wheel bearing <NUM>, the rotary seal assembly <NUM>, the annular hub chamber <NUM>, or combinations thereof. The brake drum <NUM> may also receive one or more brake pad assemblies in a manner known by those skilled in the art. In at least one configuration and as is best shown with reference to <FIG>, the brake drum <NUM> may include a brake drum flange <NUM> and at least one brake drum passage <NUM>.

The brake drum flange <NUM> may be disposed at an end of the brake drum <NUM> that may face toward the hub mounting flange <NUM>. The brake drum flange <NUM> may extend toward the axis <NUM> and may have a first brake drum flange side <NUM> and a second brake drum flange side <NUM>.

The first brake drum flange side <NUM> may face toward the hub mounting flange <NUM>. For example, the first brake drum flange side <NUM> may engage or contact the hub housing flange <NUM> or may engage or contact the hub mounting flange <NUM> if a hub housing <NUM> is not axially positioned between the hub <NUM> and the brake drum <NUM>.

The second brake drum flange side <NUM> may be disposed opposite the first brake drum flange side <NUM>. The second brake drum flange side <NUM> may face toward and may engage or contact a wheel <NUM>.

The brake drum passage <NUM> to may be configured as a through hole that may extend from the first brake drum flange side <NUM> to the second brake drum flange side <NUM>. The brake drum passage <NUM> may be aligned with and may be fluidly connected to a corresponding hub air passage <NUM>. For instance, a brake drum passage <NUM> may be disposed adjacent to and may be fluidly connected to a hub housing passage <NUM> and the hub housing passage <NUM> may be disposed adjacent to and may be fluidly connected to the hub air passage <NUM>. It is also contemplated that the axial positioning of the hub housing <NUM> and the brake drum <NUM> may be reversed, in which case the brake drum flange <NUM> may be disposed between the hub housing flange <NUM> and the hub mounting flange <NUM>. It is also contemplated that the hub housing <NUM> may be omitted and that the brake drum <NUM> may be disposed adjacent to the hub mounting flange <NUM>.

One or more seals may be provided to inhibit leakage of pressurized gas. For instance, a first seal <NUM> may be disposed between and may contact or engage the hub mounting flange <NUM> and the hub housing flange <NUM> while a second seal may be disposed between and may contact or engage the hub housing flange <NUM> and the brake drum flange <NUM>. For instance, the first seal <NUM> may contact or engage the first flange side <NUM> and may extend around the hub housing passage <NUM> while the second seal <NUM> may contact or engage the second flange side <NUM> and may extend around the hub housing passage <NUM>. The seal may have any suitable configuration. For instance, a seal may be configured as an O-ring, gasket, or the like.

Referring to <FIG>, a conduit <NUM> may fluidly connect a hub air passage <NUM> to a wheel <NUM>. In the configuration shown, two conduits <NUM> are depicted. Each conduit <NUM> may be fluidly connected to the same tire <NUM> and wheel <NUM> or may be fluidly connected to different tires <NUM> and wheels <NUM>. For instance, one conduit <NUM> may fluidly connect one hub air passage <NUM> to a first wheel <NUM> while a second conduit <NUM> fluidly connects the other hub air passage <NUM> to a second wheel <NUM>. As such, multiple tires may be inflated or deflated via the conduits <NUM>. Alternatively, a single tire <NUM> and wheel <NUM> may be mounted on the hub <NUM> and both conduits <NUM> may be fluidly connected to the same wheel <NUM>, such as via two separate fittings or tire valves that may be provided with the wheel <NUM>. As such, the volume of air that may be provided to a tire <NUM> or removed from a tire <NUM> and/or the air flow rate may be increased, which may help reduce tire inflation and/or deflation times.

In at least one configuration, each conduit <NUM> may extend through a different opening in a wheel <NUM>. A conduit <NUM> may extend from the brake drum <NUM> and may be fluidly connected to the brake drum passage <NUM>; however it is also contemplated that the conduit <NUM> may extend from the hub housing <NUM> and an associated hub housing passage <NUM> or a conduit <NUM> may extend from the hub mounting flange <NUM> and an associated hub air passage <NUM>.

The gear reduction unit <NUM>, if provided, may operatively connect the axle shaft <NUM> to the hub <NUM>. The gear reduction unit <NUM> may be at least partially disposed in the hub <NUM> and may transmit torque from the axle shaft <NUM> to the hub <NUM>. The gear reduction unit <NUM> may have any suitable configuration. For instance, the gear reduction unit <NUM> may be configured as a planetary gear set. The gear reduction unit <NUM> may be disposed proximate the distal end of the spindle <NUM> and may be received in the hub housing <NUM>.

A wheel end assembly as described above may allow a tire inflation system to route pressurized gas through a spindle and a hub rather than through external tubing or hoses that may be received inside the spindle hole or that may extend along an exterior surface of a hub, which may help reduce package space and avoid damage to which external tubing is susceptible. Routing pressurized gas through passages in a brake drum and/or hub housing may help further internalize the flow path for pressurized gas. Providing internal flow passages for pressurized gas may also help reduce potential leak paths and connection points. Providing an internal annular hub chamber may permit pressurized gas to be provided to multiple hub passages, which in turn may allow multiple tires to be inflated or may facilitate multiple fluid connections to a single tire, which may allow a greater volume of air to be provided to or exhausted from a tire and/or may decrease tire inflation and deflation times, thereby improving performance.

Claim 1:
A wheel end assembly (<NUM>) comprising:
a spindle (<NUM>) that is disposed along an axis (<NUM>) and that defines a spindle air passage (<NUM>);
a hub (<NUM>) that is rotatable about the axis (<NUM>) with respect to the spindle (<NUM>), the wheel end assembly (<NUM>) being characterized by the hub (<NUM>) defining an annular hub chamber (<NUM>) that extends around the axis (<NUM>) and a hub air passage (<NUM>) that has a first port (<NUM>) that is fluidly connected to the annular hub chamber (<NUM>) and a second port (<NUM>) that is adapted to be fluidly connected to a wheel (<NUM>); and
a rotary seal assembly (<NUM>) that fluidly connects the spindle air passage (<NUM>) to a port (<NUM>) of the annular hub chamber (<NUM>), wherein the port (<NUM>) of the annular hub chamber (<NUM>) extends continuously around the axis (<NUM>).