| 摘要 |
An accumulator for a hydraulic control system of frictional engagement mechanisms comprises a housing with a stepped bore, a first stepped piston reciprocable within the bore to form a back pressure chamber communicated with a source of line pressure, a second piston reciprocable within the first piston in a predetermind stroke to form an accumulation chamber communicated with the line pressure source, and a spring for biasing the second piston toward the accumulation chamber. In the initial stage, only the second piston is retracted against biasing force of the spring to modulate the line pressure acting on the frictional engagement mechanisms and is engaged at its retracted stroke end with the first piston. Subsequently, the first piston is retracted together with the second piston against the biasing force and the pressure in the back pressure chamber to further modulate the line pressure.
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