Patent ID: 6098682
Filing Date: 2000-08-08
Classification: B60C,Y10T

Abstract:
A vehicle tire pressure control system having a pneumatic control unit, a pressure sensor, a rotary seal associated with the tire, a wheel valve having a plurality of functional positions and being connected to and rotating with the tire, an inlet connected with a compressed air source, the control unit being connected through a connecting line and the rotary seal to the wheel valve, and the functional position of the wheel valve being controlled as a function of a pressure level in the connecting line, the wheel valve functional positions including a closed position, a open position connecting the control unit with the tire, and a venting position which opens the tire to atmosphere, the wheel valve occupying its open position as long as an inflation pressure exists in the connecting line, the wheel valve occupying its venting position as long as a venting pressure exists in the connecting line which exceeds the inflation pressure by a pre-determined amount, the wheel valve occupying its closed position as long as a closing pressure exists in the connecting line which is less than the inflation pressure by at least a pre-determined pressure difference, characterized by:a pressure level line;first and second parallel pressure lines between the compressed air source and the pressure level line;a high pressure valve in the first pressure line;a medium pressure valve in the second pressure line, the high pressure valve and the medium pressure valve each being switchable between a closed position and an open position; anda pressure reducing valve in the second pressure line for regulating an inflation pressure.