Transmission and energy accumulator assembly thereof

The invention discloses a transmission and an energy accumulator assembly thereof. The energy accumulator assembly comprises a cavity, a piston, a spool, a first elastic piece, a second elastic piece and a limiting structure, wherein one side of the cavity is open to form an opening and an oil drain hole is formed in the cavity; the piston is movably arranged in the cavity and an oil drain passage is arranged on the piston; the piston is sheathed outside the spool, the spool can axially move relative to the piston, and an oil drain chamber which is defined among the bottom wall of the cavity, the spool and the piston and is respectively communicated with one ends of the oil drain hole and the oil drain passage; the first elastic piece is arranged in the cavity, and the two ends of the first elastic piece are respectively retained between the bottom wall and the piston; the second elastic piece is arranged in the cavity and the two ends of the second elastic piece are respectively retained between the bottom w