Patent ID: 11149753

Abstract:
A controller (45) is provided with an elapse time measuring section (47A) that measures an elapse time (tx) elapsed since an initial use of an accumulator (29) based upon a reset signal from a reset switch (44), a number-of-operations measuring section (47B) that measures a number of operations of the accumulator (29), that is, a number (N) of boom lowering operations after a reset, based upon a detection signal from an accumulator side pressure sensor (39), a gas permeation amount estimating section (47C) that estimates an estimation gas permeation amount (Qloss) of the accumulator (29), a sealed gas pressure estimating section (47D) that finds an estimation sealed gas pressure (Pgs) of a gas chamber (29B) of the accumulator (29), and an accumulator degradation determining section (47E) that determines a degradation condition of the accumulator (29) and outputs the determination result.