| 摘要 |
Proportional pneumatic pressure modulator with a variable range, particularly for a clutch, including a pressure reducer 32, a relay valve 33, two solenoid valves 10 and 10' of the 3/2 type and a control device 23, characterised in that the two solenoid valves 10 and 10' are identical and normally in exhaust mode so that the said modulator can operate in two modes of use: - a first all-or-nothing mode, which corresponds to the phases of changing the ratio of the gearbox for a clutch, in which the two solenoid valves 10 and 10' are used simultaneously and in the same way like a single solenoid valve of twice the passage cross-section; - a second mode for precisely modulating the pressure, which corresponds to the progressive control of the torque transmitted upon start-up for a clutch, in which the two solenoid valves 10 and 10' are controlled by the same periodic signal with the same cyclic ratio, one of the signals being phase-shifted by a half-period with respect to the other so that the fundamentals of the pressure waves emitted to the relay valve 33 are in phase opposition and cancel each other out. <IMAGE> |
