Patent ID: 8042585

Claim:
An apparatus for controlling tire inflation pressure constructed in such a manner that pressurized air supplied from a pressure generating device is introduced into a tire air chamber of a vehicle wheel assembly through a supplying passageway provided in an axle hub and an introducing passageway provided in a wheel of the vehicle wheel assembly which is removably mounted onto a flange portion of the axle hub; wherein an outlet side end portion of the supplying passageway is opened on an outer end surface of the flange portion of the axle hub, and an inlet side end portion of the introducing passageway is opened on an inner side end surface of the wheel of the vehicle wheel assembly, and by mounting the wheel of the vehicle wheel assembly onto the flange portion of the axle hub, the outlet side end portion of the supplying passageway and the inlet side end portion of the introducing passageway are in fluid communication and air tightly joined to each other; wherein a surface formed by the outer end surface of the flange portion is substantially planar and extends along the opening of the outlet side end portion of the supplying passageway, and a surface formed by the inner side end surface of the wheel of the vehicle wheel assembly is substantially planar and extends along the opening of the inlet side end portion, wherein the first and second planes are adjacent each other, wherein the apparatus for controlling tire inflation pressure comprises a plurality of the outlet side end portions of the supplying passageways and a plurality of the inlet side end portions of the introducing passageways so that the outlet side end portions and the inlet side end portions are arranged at equiangular intervals so as to match with a mounting phase of the vehicle wheel assembly relative to the axle hub.