Central tire inflation system rotary air union

• US 9,221,308 B2
• Filed: 02/05/2013
• Issued: 12/29/2015
• Est. Priority Date: 02/06/2012
• Status: Active Grant

• Current Assignee: Pressure Systems International LLC
• Original Assignee: Stemco LP (Enpro Industries Incorporated), Pursuit LLP
• Inventors: Nelson, Christopher A., LeClaire, James, Gold, Mark
• Primary Examiner(s): Bellinger, Jason
• Application Number:
  US13/759,758
• Publication Number:
  US 20130199685A1
• Time in Patent Office: 1,057 Days
• Field of Search: 152/417, 152/415, 152/416, 301/108.1, 301/108.2, 301/108.4
• US Class Current: 1/1
• CPC Class Codes: B60B 19/08 with lubricating passages, channels, or reservoirs
• CPC Class Codes: B60B 37/00 Wheel-axle combinations, e.g. wheel sets units comprising multiple wheels arranged side-by-side B60B11/00; rail vehicle axle-boxes B61F
• CPC Class Codes: B60C 23/00318 on the wheels or the hubs
• CPC Class Codes: B60C 23/00347 comprising two or more feedthrough
• CPC Class Codes: B60C 23/00354 Details of valves
• CPC Class Codes: B60C 23/00363 Details of sealings
• CPC Class Codes: B60C 23/10 Arrangement of tyre-inflating pumps mounted on vehicles
• CPC Class Codes: B60C 29/00 Arrangements of tyre-inflating valves to tyres or rims; Accessories for tyre-inflating valves, not otherwise provided for tools for mounting or demounting valves B60C25/18

Abstract

A central tire inflation system for maintaining tire inflation on a vehicle is provided. The central tire inflation system includes a rotary union assembly having a housing that is coupled to and rotates with the hubcap. The housing is rotationally coupled to a stationary shaft. A flexible torque transfer shaft is connected to the stationary shaft on one end and to an axle plug on the other end. The axle plug has a hub forming, a bore where the hub is movable on a web of material. The flexible torque transfer shaft and hub have cooperative non-circular shapes to resist rotation. An air vent is provided in the rotary union assembly that is isolated from the lubrication area, which inhibits the pressurized air from the central tire inflation system from pressurizing the lubrication area.

Claims

1. A central tire inflation system for maintaining tire inflation on a vehicle, the central tire inflation system comprising:

an axle plug shaped to cooperatively engage a hollow axle of the vehicle, the axle plug having a bore;

a flexible torque transfer shaft having an upstream end including an air fitting positionable inside the axle and shaped to cooperatively engage the bore of the axle plug to prevent rotation therebetween and a downstream end opposite the upstream end, the flexible torque transfer shaft comprising an air conduit extending from the upstream end to the downstream end and an overmolding;

a rotary air union assembly comprising a stationary shaft and a housing rotatably coupled to the stationary shaft, wherein the flexible torque transfer shaft overmolding couples the flexible torque transfer shaft and the stationary shaft; and

a fluid flow path contained in the housing of the rotary air union assembly and in fluid communication with the air conduit.

2. The central tire inflation system of claim 1 wherein the axle plug comprises a cylindrical tube outer portion and an overmolding.

3. The central tire inflation system of claim 2 wherein the axle plug further comprises a hub having an inner surface defining the bore, and a web connecting the hub to the overmolded cylindrical tube outer portion, wherein the web allows the hub to move with respect to the overmolded cylindrical tube outer portion.

4. The central tire inflation system of claim 3, wherein the inner surface comprises a non-round shape and the flexible torque transfer shaft has an outer surface shaped to cooperatively engage the non-round shape such that the non-round shape resists rotation.

5. The central tire inflation system of claim 4 wherein the non-round shape is a polygon.

6. The central tire inflation system of claim 3 wherein the inner surface comprises a rib.

7. The central tire inflation system of claim 6 wherein the rib comprises at least two surfaces that extend inwardly from the inner surface and converge at an apex.

8. The central tire inflation system of claim 1 wherein the flexible torque transfer shaft overmolding comprises a plurality of channels.

9. The central tire inflation system of claim 1 wherein the fluid flow path comprises a first fluid flow path to a first tire and a second fluid flow path to a second tire.

10. The central tire inflation system of claim 9 wherein the first fluid flow path and the second fluid flow path are isolated from each other by a plurality of check valves.

11. The central tire inflation system of claim 1 wherein the housing comprises a plurality of spokes extending inwardly from the housing that are coupled to a central hub and the stationary shaft extends from the central hub.

12. The central tire inflation system of claim 11 wherein the housing comprises an air vent and at least one of the plurality of spokes defines an air vent passage.

13. An apparatus configured for coupling to a hubcap and a hollow axle to place a fluid source in communication with a tire, the apparatus comprising:

a rotary union assembly to couple to the hubcap of a vehicle, the rotary union assembly comprising;

a housing to couple to the hubcap, a plurality of spokes formed with the housing and extending radially inwardly from the housing, a central hub coupled to the plurality of spokes, a stationary shaft coupled to and extending from the central hub in a direction toward the hollow axle, and a fluid flow passage extending through the stationary shaft into the central hub and through at least one of the plurality of spokes to an outer surface of the housing, wherein the housing of the rotary union assembly comprises at least one lubrication flow passage formed by the housing, the plurality of spokes, and the central hub wherein the lubrication flow passage is isolated from the fluid flow passage;

an axle plug sized to cooperatively engage the hollow axle; and

a flexible torque transfer shaft extending through the axle plug and engaged with the axle plug to prevent rotation therebetween, the flexible torque transfer shaft coupled to the stationary shaft and comprising;

an air conduit having an upstream side and a downstream side, the downstream side in fluid communication with the fluid flow passage, and an elastomer overmold covering the air conduit and at least a portion of the stationary shaft, wherein the elastomer overmold resists rotation of the stationary shaft.

14. The apparatus of claim 13, wherein the axle plug defining a bore shape such that the flexible torque transfer shaft slidably engages the bore.

15. A vehicle having at least one wheel and a central tire inflation system comprising:

a hubcap defining a lubrication cavity;

a sight window defining a sight glass lubrication cavity, the sight window comprising a lubrication cavity vent;

a rotary union assembly residing between and coupled to the hubcap and the sight window, the rotary union assembly having a housing defining an outer circumference and a plurality of spokes extending radially inward from the housing to a central hub, the rotary union comprising a plurality of lubrication flow passages formed by the housing, plurality of spokes, and central hub such that the lubrication cavity and the sight window lubrication cavity are in fluid communication;

a flexible torque transfer shaft having a rotary union assembly side coupled to the rotary union assembly and an axle side opposite the rotary union assembly side, the flexible torque transfer shaft comprising an air conduit;

an axle plug to cooperatively engage an axle of the vehicle and a bore sized to slidingly engage the flexible torque transfer shaft, wherein the axle plug is positioned between the rotary union assembly side and the axle side; and

an air path is contained in the air conduit and the rotary union assembly to place an air source in fluid communication with a tire.

16. The vehicle of claim 15 further comprising a tire pressure monitoring system in fluid communication with the air path.

17. The vehicle of claim 16 wherein the rotary union assembly comprises at least one service port and the tire pressure monitoring system comprises at least one pressure port in fluid communication with the at least one service port.

18. A vehicle having at least one wheel and a central tire inflation system comprising:

a hubcap defining a lubrication cavity;

a sight window defining a sight window lubrication cavity, the sight window comprising a lubrication cavity vent;

a pressure monitor coupled to the hubcap;

a rotary union assembly residing between and coupled to the hubcap and the sight window, the rotary union assembly having a housing defining an outer circumference and a plurality of spokes extending radially inward from the housing to a central hub, the rotary union comprising a plurality of lubrication flow passages formed by the housing, plurality of spokes, and central hub such that the lubrication cavity and the sight window lubrication cavity are in fluid communication;

a flexible torque transfer shaft having a rotary union assembly side coupled to the rotary union assembly and an axle side opposite the rotary union assembly side, the flexible torque transfer shaft comprising an air conduit;

an axle plug to cooperatively engage an axle of the vehicle and a bore sized to slidingly engage the flexible torque transfer shaft, wherein the axle plug is positioned between the rotary union assembly side and the axle side; and

an air path is contained in the air conduit and the rotary union assembly to place an air source in fluid communication with a tire and the pressure monitor.