An apparatus for delivering air through a powered axle assembly for use in automatic tire inflation systems. The apparatus comprises a base attachable to a non-rotating structure within the axle assembly and having the drive axle extend therethrough. A rotor is mountable in the axle assembly for rotation with the drive axle and for forming an air chamber between the rotor and the base and extending about the drive axle. An annular sealing member in sealing engagement with the rotor and the base is disposed within the air chamber and is rotatable with the rotor and with respect to the base. The base includes at least one air inlet for delivering air in a radial direction into the air chamber and the rotor includes at least one air outlet for air flow out of the chamber.

A tire inflation system including an axle housing and a sealing ring disposed on the axle housing. The sealing ring has a conduit formed therethrough. A hub is rotatably disposed on the axle housing. The hub is disposed adjacent the sealing ring and has a conduit formed therethrough which is in fluid communication with a conduit formed through a fastener engaged with the hub. The tire inflation system also includes an inner rotary seal disposed between the sealing ring and the hub and an outer rotary seal disposed between the sealing ring and the hub. The conduit formed through the hub is in fluid communication with the conduit formed through the sealing ring through an area between the inner rotary seal and the outer rotary seal. A bearing seal is disposed between the hub and the axle housing and outboard of the outer rotary seal.

Valves and related systems are described for equalization of pressure between vehicle tires. Valves may, for example, comprise a valve body which selectively opens when a vehicle is in motion so as to selectively allow two-way communication between vehicle tires.

A rotary transmission apparatus (1) for the transmission of control and/or working pressures to a fluid duet (51) which is received or configured at least in regions in the interior of a shaft (50), in particular, a drive shaft. The rotary transmission apparatus (1) has a stator assembly (2) which is arranged in a stationary manner with respect to a rotational movement of the shaft (50) and has at least one fluid feed/discharge line (3) and a control element (4) which can be displaced in the shaft longitudinal direction (L) relative to the shaft (50) between a first position and a second position. A flow connection between the at least one fluid feed/discharge line (3) and the fluid duct (51) is interrupted in the first position of the control element (4), and a flow connection between the at least one fluid feed/discharge line (3) and the fluid duct (51) is established in the second position of the control element (4).