Patent Description:
A rotary union for a tire inflation system is disclosed in <CIT>. <CIT> discloses a tire inflation system that includes a torque transfer sleeve provided with a hexagonal sleeve hole serving as an anti-rotation feature engaging with a stator of the rotary union and with a spindle plug. <CIT> discloses an assembly for a tire inflation system that includes a bearing coupled to a rotary joint spindle adjacent to a pair of rotary air seals in which the bearing has an outer race to which a bearing housing is coupled. An alternative is needed to the prior art designs.

The invention addresses this need by providing an axle assembly configured as defined in claim <NUM>. The axle assembly includes: a spindle that defines a spindle hole that is disposed along an axis; a hub that is rotatable about the axis with respect to the spindle; a spindle plug that is disposed in the spindle hole and is fixedly positioned with respect to the spindle, the spindle plug defining an opening; a hose that extends through the opening; a rotary union having a stator and a rotatable fitting that is fluidly connected to the hose and rotatable about the axis with respect to the stator, wherein the rotatable fitting is adapted to be fluidly connected to a tire; and a sleeve that receives or encircles the hose and that extends from the spindle plug to the stator, wherein the sleeve cooperates with the spindle plug to limit rotation of the stator and the hose about the axis. The sleeve has a first end, a second end that is disposed opposite the first end, a sleeve hole that extends from the first end to the second end, and at least one anti-rotation feature that extends between the first end and the second end and that is disposed outside of the sleeve hole. The anti-rotation feature engages the spindle plug to resist rotation of the sleeve about the axis.

At least a portion of the hose may extend along the axis.

The sleeve may extend through the opening.

The hub may include a hub cap that defines a hub cap cavity. The spindle plug may define a vent opening that that allows air to pass between the spindle hole and the hub cap cavity.

The spindle plug may define a sensor opening that receives a sensor.

The hose may be received inside the stator. The sleeve may limit rotation of the stator and the hose about the axis.

The sleeve may have an enlarged portion that extends from the first end and an elongated portion that extends from the second end to the enlarged portion. The enlarged portion may extend further from the axis than the elongated portion. The anti-rotation feature may provided with the elongated portion.

The anti-rotation feature may extend from the enlarged portion toward the second end.

The anti-rotation feature may be configured as a rib that extends axially from the enlarged portion toward the second end.

A gap may be provided between the sleeve and the hose that permits the sleeve to disengage the stator when the enlarged portion is squeezed toward the axis.

The sleeve may include a stop feature that extends away from the axis and that is disposed proximate the second end. The stop feature may be engageable with the spindle plug to inhibit the sleeve from being removed from the opening.

The spindle plug may be axially positioned between the enlarged portion and the stop feature.

The enlarged portion may extend further from the axis than the elongated portion. The stop feature may encircle the elongated portion and is disposed at an end of the anti-rotation feature.

The sleeve may have an enlarged portion that extends from the first end and an elongated portion that extends from the second end to the enlarged portion. A stator engaging anti-rotation feature may be provided inside the enlarged portion that extends from the first end toward the elongated portion. The stator engaging anti-rotation feature may mate with the stator to limit rotation of the sleeve with respect to the stator.

The enlarged portion may have a retention feature that is spaced apart from the first end and that extends at least partially around that axis. The retention feature may mate with the stator to inhibit axial movement of the sleeve with respect to the stator.

The retention feature may encircle the axis and intersect the stator engaging anti-rotation feature.

The rotary union may include a torque tube that fluidly connects the stator to the rotatable fitting. The rotatable fitting may be rotatable about the axis with respect to the torque tube. The torque tube may be received inside the stator and the hose.

A hose retainer may encircle the hose and secure the hose to the stator. The hose retainer may be at least partially received inside the stator, received inside the sleeve, and spaced apart from the sleeve.

Referring to <FIG>, portion of an axle assembly <NUM> is shown. The axle assembly <NUM> may be provided with a vehicle like a truck, bus, farm equipment, mining equipment, military transport or weaponry vehicle, cargo loading equipment for land, air, or marine vessels, or a trailer for transporting cargo.

As an overview, the axle assembly <NUM> may be associated with a tire inflation system <NUM> that may help obtain and/or maintain a desired pressure within one or more tires <NUM>. The tire inflation system <NUM> may be disposed on the vehicle and may be configured to provide a pressurized gas or pressurized gas mixture to one or more tires <NUM>, exhaust the pressurized gas or pressurized gas mixture from one or more tires <NUM>, or both. For clarity, the term "pressurized gas" may refer to a pressurized gas mixture (e.g., air) or a purified pressurized gas or gas mixture (e.g., nitrogen). 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 or gas mixture (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 <NUM> may be fluidly connected to a pressurized gas source <NUM>. 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 <NUM>. The pressurized gas source <NUM> may be disposed on the vehicle and may be fluidly connected to at least one tire <NUM> via passages in various components.

The axle assembly <NUM> may be configured to support one or more wheels <NUM>. The axle assembly also be configured to support a brake assembly <NUM>, such as a friction brake like a disc brake or drum brake. The axle assembly <NUM> may be provided in a steerable configuration or a non-steerable configuration. In a steerable configuration, the axle assembly <NUM> may be a steerable structural component, such as a steering knuckle. In at least one configuration, the axle assembly <NUM> includes a spindle <NUM>, a hub <NUM>, , a spindle plug <NUM>, a hose <NUM>, a rotary union <NUM>, and a sleeve <NUM>. The axle assembly <NUM> may also include one or more wheel bearings <NUM>, a hub seal <NUM>, and one or more hose assemblies <NUM>.

The spindle <NUM> may be disposed along or may extend around an axis <NUM>. The spindle <NUM> may be fixedly positioned with respect to a structural component <NUM>, such as a steering knuckle or an axle housing. It is 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> defines a spindle hole <NUM>.

The spindle hole <NUM> is disposed along the axis <NUM>. The spindle hole <NUM> may be a through hole that may extend through the spindle <NUM>. The spindle hole <NUM> may receive various components, such as the spindle plug <NUM>, the hose <NUM>, and the sleeve <NUM>. In a drive axle configuration, the spindle hole <NUM> may also receive an axle shaft that may operatively connect a power source or torque source such as an engine or electric motor to the hub <NUM> to help propel the vehicle.

The hub <NUM> is rotatable about the axis <NUM> with respect to the spindle <NUM>. In addition, the hub <NUM> may facilitate mounting of at least one wheel <NUM>. In at least one configuration, the hub <NUM> may include a hub cavity <NUM>, a hub mounting flange <NUM>, and a hub cap <NUM>.

The hub cavity <NUM> may be disposed inside the hub <NUM> and may be encircled by the hub <NUM>. As such, 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 axle assembly <NUM>, such as the spindle <NUM>, one or more wheel bearings <NUM>, and the hub seal <NUM>.

The hub mounting flange <NUM> may facilitate mounting of at least one wheel <NUM>. For example, the hub mounting flange <NUM> may extend around the axis <NUM> and 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>, 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.

The hub cap <NUM> may be disposed proximate an outboard end of the hub <NUM>. The hub cap <NUM> may help enclose the hub cavity <NUM>. In at least one configuration, the hub cap <NUM> define a hub cap cavity <NUM> that may receive at least a portion of the rotary union <NUM>.

One or more wheel bearings <NUM> may be disposed on the spindle <NUM> and may rotatably support the hub <NUM>. In the configuration shown, two wheel bearings <NUM> are illustrated. A wheel bearing <NUM> may have any suitable configuration. For instance, a 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 encircle and may engage the spindle <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>. The hub seal <NUM> may be disposed near an inboard end of the hub <NUM> that may be disposed opposite the hub cap <NUM>. The hub <NUM>, hub seal <NUM>, and the hub cap <NUM> may cooperate to inhibit contaminants from entering the hub cavity <NUM>.

Referring primarily to <FIG>, the spindle plug <NUM> is disposed in the spindle hole <NUM>. The spindle plug <NUM> is fixedly positioned with respect to the spindle <NUM>. As such, the spindle plug <NUM> may not rotate about the axis <NUM> with respect to the spindle <NUM>. The spindle plug <NUM> defines an opening <NUM> and may be fixed to the spindle <NUM> in any suitable manner, such as with an interference fit, weld, threaded connection, one or more fasteners, or the like.

Referring primarily to <FIG> and <FIG>, the spindle plug <NUM> may be made of one or more components. In at least one configuration, the spindle plug <NUM> may include a body <NUM> and an insert <NUM>. The body <NUM> and the insert <NUM> are illustrated as being separate parts; however it is contemplated that the body <NUM> and the insert <NUM> may be provided as a unitary one-piece component.

The body <NUM> may extend from the spindle <NUM> toward the axis <NUM>. In at least one configuration, the body <NUM> may include an annular wall <NUM> and a plug wall <NUM>. The annular wall <NUM> may extend around or encircle the axis <NUM> and may engage the spindle <NUM>. The plug wall <NUM> may extend from the annular wall <NUM> toward the axis <NUM>. The plug wall <NUM> may define an opening <NUM> that may receive the insert <NUM>.

The insert <NUM> may be at least partially received in the opening <NUM>. In at least one configuration, the insert <NUM> may define a groove that may receive the plug wall <NUM> to inhibit movement of the insert <NUM> with respect to the body <NUM>. The insert <NUM> may define one or more holes or openings. For instance, the insert <NUM> may include an opening <NUM>, which may also be referred to as a hose opening. The insert <NUM> may also include a vent opening <NUM>, a sensor opening <NUM>, or both.

The opening <NUM> may be configured as a through hole through which the hose <NUM> and the sleeve <NUM> may extend. In at least one configuration, the opening <NUM> may be disposed at or near the center of the insert <NUM>. For instance, the opening <NUM> may extend along the axis <NUM>. The opening <NUM> may be provided with a cross-sectional shape that may inhibit rotation of the sleeve <NUM>. For instance, the opening <NUM> may have a noncircular shape or noncircular profile that may receive the sleeve <NUM> such that one or more surfaces of the insert <NUM> that define the opening <NUM> may engage the sleeve <NUM> and resist or limit rotation twisting of the sleeve <NUM> about the axis <NUM>. In the configuration shown and as is best shown in <FIG>, the opening <NUM> may have one or more recesses <NUM> that extend away from the axis <NUM>. An arcuate wall <NUM> may extend from one recess <NUM> to an adjacent recess <NUM> when multiple recesses are provided. The arcuate wall <NUM> may be radially disposed with respect to the axis <NUM>. The recesses <NUM> and arcuate walls <NUM> may engage or mate with a portion of the sleeve <NUM> having a similar profile to resist twisting or rotation of the sleeve <NUM> as will be discussed in more detail below. It is contemplated that the opening <NUM> may be provided in different configurations that may or may not include recesses <NUM> and arcuate walls <NUM>. For instance, the opening <NUM> may be configured as a noncircular shape such as an oval, triangle, quadrilateral, or shape having additional sides.

Referring primarily to <FIG>, <FIG>, and <FIG>, the vent opening <NUM> may be configured as a through hole that may allow air to pass between the spindle hole <NUM> and the hub cap cavity <NUM>. The vent opening <NUM> may be spaced apart from the opening <NUM>. In at least one configuration, the spindle hole <NUM> may be fluidly connected to the surrounding environment via a port. As such, the vent opening <NUM> may allow pressure to equalize between the hub cap cavity <NUM> and the surrounding environment. A filter <NUM> may be received in the vent opening <NUM>. The filter <NUM> may inhibit contaminants from entering the hub cap cavity <NUM>.

The sensor opening <NUM> may be configured as a through hole that may receive a sensor <NUM>. The sensor may be of any suitable type. For instance, the sensor <NUM> may be an accelerometer, temperature sensor, vibration sensor, or the like that may provide a signal indicative of the environment inside the hub cavity <NUM> or an attribute of a component disposed proximate the wheel end or disposed inside the hub cavity <NUM>. For instance, the sensor <NUM> may provide a signal indicative of the operating state of one or more wheel bearings <NUM>. As an example, a signal that is indicative of elevated temperature or vibrational characteristics may be indicative of wear or substandard performance of a wheel bearing <NUM>.

Referring primarily to <FIG> and <FIG>, the hose <NUM> may fluidly connect the pressurized gas source <NUM> to the rotary union <NUM>. In at least one configuration, the hose <NUM> or a portion thereof may extend along the axis <NUM>. The hose <NUM> may be made of any suitable material, such as a polymeric material. The hose <NUM> may be fluidly coupled to a hose fitting that may be provided with a through hole in the axle assembly to facilitate a fluid connection to the pressurized gas source <NUM>. As such, one end of the hose <NUM> may be mounted to a portion of the axle assembly such as the spindle or axle housing while the other end may be mounted to or fluidly connected to the rotary union <NUM>.

The rotary union <NUM> may be configured to fluidly connect the hose <NUM> to one or more hose assemblies <NUM>. In at least one configuration and as is best shown with reference to <FIG> and <FIG>, the rotary union <NUM> includes a stator <NUM> and a rotatable fitting <NUM> and may include a torque tube <NUM>, and a hose retainer <NUM>.

The torque tube <NUM> may be a hollow tube that may be disposed along the axis <NUM>. The torque tube <NUM> may have a first end and a second end. The first end may be fluidly connected to the hose <NUM>. For instance, the first end may be received inside of the hose <NUM> and may engage or contact the hose <NUM>. The second end may be disposed opposite the first end. For example, the second end may face toward and may be received inside the rotatable fitting <NUM>. As such, the torque tube <NUM> may provide a fluid connection between the hose <NUM> and the rotatable fitting <NUM>. In at least one configuration, the torque tube <NUM> may include a protrusion <NUM> and a stator retaining feature <NUM>.

The protrusion <NUM> may inhibit axial movement of the torque tube <NUM>. The protrusion <NUM> may extend away from the axis <NUM> and may partially or completely extend around the axis <NUM>.

The stator retaining feature <NUM> may couple the stator <NUM> to the torque tube <NUM>. In at least one configuration, the stator retaining feature <NUM> may be configured as a barb, recess, or barb and recess that may engage or be received inside of the stator <NUM> and that may inhibit axial movement of the stator <NUM> with respect to the torque tube <NUM>. It is also contemplated that that stator retaining feature <NUM> may be provided as an interference fit and may not include a barb, a recess, or both.

Referring to <FIG>, the stator <NUM> may extend from the torque tube <NUM> in a direction that extends toward the spindle plug <NUM>. The stator <NUM> may be received inside of the hub cap cavity <NUM> and may be spaced apart from the rotatable fitting <NUM>. In at least one configuration, the stator <NUM> may include an end wall <NUM>, a first socket wall <NUM>, and a second socket wall <NUM>.

The end wall <NUM> may be disposed at an end of the stator <NUM>. The end wall <NUM> may be received inside of the rotatable fitting <NUM>. The end wall <NUM> may define a hole through which the torque tube <NUM> may extend.

The first socket wall <NUM> may extend from the end wall <NUM> in a direction that extends toward the spindle plug <NUM>. The first socket wall <NUM> may encircle the axis <NUM>, the torque tube <NUM>, and optionally a portion of the hose <NUM>. The first socket wall <NUM> may have a larger inside diameter than the hole in the end wall <NUM>. In addition, the first socket wall <NUM> may engage the hose <NUM>, the torque tube <NUM>, or both. The first socket wall <NUM> may be received inside the rotatable fitting <NUM>. A seal <NUM> such as an O-ring may extend from the torque tube <NUM> to the first socket wall <NUM>.

The second socket wall <NUM> may extend from the first socket wall <NUM> in a direction that extends toward the spindle plug <NUM>. The second socket wall <NUM> may encircle the axis <NUM>, the torque tube <NUM>, a portion of the hose <NUM>, and the hose retainer <NUM>. The second socket wall <NUM> or a portion thereof may have a larger outside diameter than the first socket wall <NUM>, a larger inside diameter than the first socket wall <NUM>, or both. A seal <NUM> such as an O-ring may extend from the hose <NUM> away from the axis <NUM> to an interior side of the second socket wall <NUM>. In at least one configuration, the second socket wall <NUM> may include one or more anti-rotation elements <NUM> and a retaining element <NUM>.

Referring primarily to <FIG>, one or more anti-rotation elements <NUM> may be provided that may engage the sleeve <NUM> to help inhibit rotation of the sleeve <NUM> with respect to the stator <NUM>. An anti-rotation element <NUM> may have any suitable configuration. For instance, an anti-rotation element <NUM> may have a male configuration, a female configuration, or both. In the configuration shown, the anti-rotation elements <NUM> are configured as ribs that extend from an exterior side of the second socket wall <NUM> in a direction that extends away from the axis <NUM>. A plurality of anti-rotation elements <NUM> may be provided that may be spaced apart from each other and may be arranged around the axis <NUM>. In at least one configuration, the anti-rotation elements <NUM> or a portion thereof may extend parallel or substantially parallel to the axis <NUM>.

Referring to <FIG> and <FIG>, the retaining element <NUM> may be configured to couple the sleeve <NUM> to the stator <NUM> to resist axial movement of the sleeve <NUM>. The retaining element <NUM> may have any suitable configuration. For example, the retaining element <NUM> may have a male configuration, a female configuration, or both. In the configuration shown, the retaining element <NUM> has a male configuration and is configured as a protrusion that extends from the exterior side of the second socket wall <NUM> in a direction that extends away from the axis <NUM>. The retaining element <NUM> may extend partially or continuously around the axis <NUM>.

Referring primarily to <FIG>, the hose retainer <NUM> may help secure the hose <NUM> to the stator <NUM>. The hose retainer <NUM> may be received inside the second socket wall <NUM> and may extend from the outside diameter of the hose <NUM> to the second socket wall <NUM>. As such, the hose retainer <NUM> may encircle the hose <NUM> and may be at least partially received inside of the stator <NUM>. The hose retainer <NUM> may also help inhibit axial movement of the seal <NUM>. The hose retainer <NUM> may be received inside the sleeve <NUM> and may be spaced apart from or separated from at least a portion of the sleeve <NUM> as will be discussed in more detail below.

Referring primarily to <FIG> and <FIG>, the rotatable fitting <NUM>, which may also be called a tee fitting, is rotatable about the axis <NUM> with the hub <NUM>. In addition, the rotatable fitting <NUM> may be spaced apart from and rotatable with respect to the hose <NUM>, the sleeve <NUM>, the torque tube <NUM>, and the stator <NUM>. For instance, a bearing <NUM> may extend from the torque tube <NUM> to the rotatable fitting <NUM> to facilitate rotation of the rotatable fitting <NUM> with respect to torque tube <NUM> and the stator <NUM>. One or more seals <NUM> may also extend from the torque tube <NUM> to the rotatable fitting <NUM> to help inhibit the leakage of pressurized gas. In the configuration shown, seals <NUM> encircle the torque tube <NUM> and are axially positioned on opposite sides of the bearing <NUM>. As such, the rotatable fitting <NUM> may be rotatable about the axis <NUM> with respect to the torque tube <NUM> and the stator <NUM>. The rotatable fitting <NUM> may fluidly connect the torque tube <NUM> to one or more hose assemblies <NUM>. As such, the rotatable fitting <NUM> is adapted to be fluidly connected to a tire <NUM>.

Referring primarily to <FIG>, the sleeve <NUM> receives or encircle the hose <NUM>. In addition, the sleeve <NUM> may be spaced apart from or may engage the hose <NUM>. In at least one configuration, the sleeve <NUM> may be made of a flexible or resilient material, such as a polymeric material, rubber, or the like. The sleeve <NUM> cooperates with the spindle plug <NUM> to limit rotation of the stator <NUM> and the hose <NUM> about the axis <NUM> as will be discussed in more detail below.

The sleeve <NUM> extends from the spindle plug <NUM> to the rotary union <NUM>. For instance, the sleeve <NUM> extends through the opening <NUM> of the spindle plug <NUM> to the stator <NUM> of the rotary union <NUM>. According to the invention and as is best shown in <FIG>, the sleeve <NUM> has a first end <NUM>, a second end <NUM>, a sleeve hole <NUM>, and at least one anti-rotation feature <NUM>. The sleeve <NUM> may also include an enlarged portion <NUM>, an elongated portion <NUM>, a stop feature <NUM>, or combinations thereof.

Referring primarily to <FIG> and <FIG>, the first end <NUM> may face toward the rotary union <NUM>. As such, the first end <NUM> may be engageable with the rotary union <NUM>.

The second end <NUM> is disposed opposite the first end <NUM>. As such, the second end <NUM> may face away from the rotary union <NUM>. The second end <NUM> may be received inside of the spindle hole <NUM>.

The sleeve hole <NUM> extends from the first end <NUM> to the second end <NUM>. The hose <NUM> and a portion of the rotary union <NUM> may be received in the sleeve hole <NUM>. For instance, a portion of the stator <NUM> and optionally the torque tube <NUM> may be received in the sleeve hole <NUM>.

Referring primarily to <FIG> and <FIG>, the enlarged portion <NUM> may extend from the first end <NUM>. The enlarged portion <NUM> may extend further away from the axis <NUM> than the elongated portion <NUM> and may have a larger outside diameter than the elongated portion <NUM>. In at least one configuration, the enlarged portion <NUM> may include one or more stator engaging anti-rotation features <NUM> and a retention feature <NUM>.

Referring primarily to <FIG>, one or more stator engaging anti-rotation features <NUM> may be provided inside the enlarged portion <NUM>. A stator engaging anti-rotation feature <NUM> may extend from the first end <NUM> toward the elongated portion <NUM>. A stator engaging anti-rotation feature <NUM> may mate with a corresponding anti-rotation element <NUM> of the stator <NUM> to help limit rotation of the sleeve <NUM> about the axis <NUM> with respect to the stator <NUM>. The stator engaging anti-rotation feature <NUM> may have any suitable configuration that is compatible with the configuration of the anti-rotation element <NUM> of the stator <NUM>, such as a male configuration, female configuration, or combinations thereof. In the configuration shown, the stator engaging anti-rotation feature <NUM> is configured as a groove that receives the anti-rotation element <NUM> of the stator <NUM>.

The retention feature <NUM> may also be provided inside the enlarged portion <NUM>. The retention feature <NUM> may mate with the retaining element <NUM> of the stator <NUM> to inhibit axial movement of the sleeve <NUM> with respect to the stator <NUM>. The retention feature <NUM> may be disposed near the first end <NUM>. For instance, the retention feature <NUM> may be spaced apart from the first end <NUM> and may extend partially or continuously around the axis <NUM>. The retention feature <NUM> may have any suitable configuration that is compatible with the configuration of the retaining element <NUM> of the stator <NUM>, such as a male configuration, female configuration, or combinations thereof. In the configuration shown, the retention feature <NUM> is configured as a groove that receives the retaining element <NUM> of the stator <NUM>. The retention feature <NUM> may intersect or extend from one or more of the stator engaging anti-rotation features <NUM>.

Referring to <FIG>, at least a portion of the enlarged portion <NUM> may be spaced apart from the hose <NUM> and the stator <NUM> of the rotary union <NUM> such that a gap <NUM> may be formed between the enlarged portion <NUM> of the sleeve <NUM> and the hose <NUM>. The gap <NUM> may be positioned closer to the axis <NUM> than a tapered portion <NUM> of the sleeve <NUM> that extends from the elongated portion <NUM>. The tapered portion <NUM> may be knurled or provided with a texture that helps provide friction for gripping the sleeve <NUM>.

Referring to <FIG>, the sleeve <NUM> may be configured to disengage the stator <NUM> when the enlarged portion <NUM> is squeezed toward the axis <NUM> and the hose <NUM>. For example, compressing the tapered portion <NUM> toward the axis <NUM> may cause the sleeve <NUM> to flex and expand at the first end <NUM> so that the retention feature <NUM> may move away from the axis <NUM> and may at least partially disengage the retaining element <NUM> of the stator <NUM>.

Referring to <FIG>, the elongated portion <NUM> may extend from the second end <NUM> to the enlarged portion <NUM>. One or more anti-rotation features <NUM> may be provided with the elongated portion <NUM>. An anti-rotation feature <NUM> may have any suitable configuration that is compatible with the anti-rotation elements <NUM> of the stator <NUM>. For instance, an anti-rotation feature <NUM> may have a male configuration, a female configuration, or both. In the configuration shown, the anti-rotation features <NUM> are configured as ribs that extend from an exterior side of the elongated portion <NUM> in a direction that extends away from the axis <NUM>. As such, the anti-rotation features <NUM> is disposed outside of the sleeve hole <NUM>. A plurality of anti-rotation features <NUM> may be provided that may be spaced apart from each other and may be arranged around the axis <NUM>. The anti-rotation features <NUM> or a portion thereof may extend parallel or substantially parallel to the axis <NUM>. In at least one configuration, and an anti-rotation feature <NUM> may extend from the enlarged portion <NUM> toward or to the second end <NUM>.

The sleeve <NUM> cooperates with the spindle plug <NUM> to resist or limit rotation of the stator <NUM> and the hose <NUM> about the axis <NUM>. The recesses <NUM> of the spindle plug <NUM> may engage or mate with the anti-rotation features <NUM> of the sleeve <NUM> to resist or limit rotation of the sleeve <NUM> about the axis <NUM> with respect to the spindle plug <NUM>. The stator engaging anti-rotation features <NUM> of the sleeve <NUM> may engage or mate with the anti-rotation elements <NUM> of the stator <NUM> to resist or limit rotation of the stator <NUM> about the axis <NUM>, thereby resisting or limiting rotation of the hose <NUM> in the torque tube <NUM> about the axis <NUM>. The sleeve <NUM> may be configured to permit limited twisting between the spindle plug <NUM> and the stator <NUM>. Twisting of the sleeve <NUM> may store energy in the sleeve <NUM> such that the sleeve <NUM> will further resist twisting and be biased to return to an untwisted state.

Referring primarily to <FIG>, <FIG>, and <FIG>, the stop feature <NUM> may be engageable with the spindle plug <NUM> to inhibit removal of the sleeve <NUM> from the spindle plug <NUM>. The stop feature <NUM> may be disposed proximate the second end <NUM> of the sleeve <NUM>. In at least one configuration, the stop feature <NUM> may encircle the elongated portion <NUM> and may be disposed at an end of one or more anti-rotation features <NUM> of the sleeve <NUM>. The stop feature <NUM> may extend away from the axis <NUM> further than at least a portion of the opening <NUM> of the spindle plug <NUM> that receives the sleeve <NUM>. The spindle plug <NUM> may be axially positioned between the enlarged portion <NUM> of the sleeve <NUM> and the stop feature <NUM>. As such, moving the sleeve <NUM> to the left from the perspective shown in <FIG> may move the stop feature into engagement with the inboard side of the plug wall <NUM> of the spindle plug <NUM>, and thereby inhibit the sleeve <NUM> from being pulled through the opening <NUM> and removed from the spindle plug <NUM>.

Referring to <FIG>, a hose assembly <NUM> may fluidly connect the rotatable fitting <NUM> to a tire <NUM>. In the configuration shown, two hose assemblies <NUM> are depicted. Each hose assembly <NUM> may be fluidly connected to a different tire <NUM>. A hose assembly <NUM> may have a first end and a second end. The first end may be connected to the rotatable fitting <NUM>. The second end may be disposed opposite the first end and may be fluidly connected to a tire <NUM>. For instance, the second end may be mounted to a tire valve <NUM> that may extend through a hole in the wheel <NUM> and that may permit gas to enter or exit the tire <NUM> when the tire valve <NUM> is open. The hose assembly <NUM> may be configured to hold the tire valve <NUM> in an open position when secured to the tire valve <NUM>. Moreover, the tire valve <NUM> may close when the hose assembly <NUM> is disengaged from the tire valve <NUM> to prevent deflation of the tire <NUM>.

Providing an axle assembly with a rotary fitting and sleeve as described above may allow the sleeve to help limit or prevent twisting of the torque tube and the hose, which may occur if the rotatable fitting becomes stuck or is otherwise inhibited from rotating with respect to the stator when the hub rotates. The resistance torque provided by the sleeve via its connection with the spindle plug helps resist and limit rotation of the stator, torque tube, and the hose. Limiting or preventing twisting of the hose inside the spindle may prevent the hose from kinking or being disengaged, thereby maintaining proper functionality of the tire inflation system and avoiding repairs and associated costs. The sleeve and spindle plug may cooperate to help maintain alignment of the hose. The stop feature of the sleeve and spindle plug may cooperate to resist inadvertent removal of the sleeve from the spindle plug during assembly or maintenance. The sleeve may also be easily installable and removable with a "pinch and pull" configuration.

Claim 1:
An axle assembly (<NUM>) comprising:
a spindle (<NUM>) that defines a spindle hole (<NUM>) that is disposed along an axis (<NUM>);
a hub (<NUM>) that is rotatable about the axis (<NUM>) with respect to the spindle (<NUM>);
a spindle plug (<NUM>) that is disposed in the spindle hole (<NUM>) and is fixedly positioned with respect to the spindle (<NUM>), the spindle plug (<NUM>) defining an opening (<NUM>);
a hose (<NUM>) that extends through the opening (<NUM>);
a rotary union (<NUM>) having a stator (<NUM>) and a rotatable fitting (<NUM>) that is fluidly connected to the hose (<NUM>) and rotatable about the axis (<NUM>) with respect to the stator (<NUM>), wherein the rotatable fitting (<NUM>) is adapted to be fluidly connected to a tire (<NUM>); and
a sleeve (<NUM>) that receives the hose (<NUM>) and that extends from the spindle plug (<NUM>) to the stator (<NUM>), wherein the sleeve (<NUM>) cooperates with the spindle plug (<NUM>) to limit rotation of the stator (<NUM>) and the hose (<NUM>) about the axis (<NUM>), wherein the sleeve (<NUM>) has a first end (<NUM>), a second end (<NUM>) that is disposed opposite the first end (<NUM>), a sleeve hole (<NUM>) that extends from the first end (<NUM>) to the second end (<NUM>), and at least one anti-rotation feature (<NUM>) that extends between the first end (<NUM>) and the second end (<NUM>) wherein the anti-rotation feature (<NUM>) engages the spindle plug (<NUM>) to resist rotation of the sleeve (<NUM>) about the axis (<NUM>);
characterised in that the anti-rotational feature (<NUM>) is disposed outside of the sleeve hole (<NUM>).