Hydraulic actuation unit, particularly for controlling the starting and stopping of hydraulic motors

A hydraulic actuation unit, for controlling the starting and stopping of hydraulic motors, comprising:

• a first main circuit and a second main circuit, which are adapted to connect selectively a supply of pressurized working liquid and a tank to a hydraulic motor;
• a first recirculation circuit and a second recirculation circuit for returning respectively a fraction of said working liquid from said second main circuit to said first main circuit and vice versa;
• a counterbalancing valve, which comprises a shuttle that can switch to a first end position and a second end position, which correspond to the actuation of said motor with mutually opposite directions of rotation, and comprises a first passage channel and a second passage channel, which are arranged respectively along said first main circuit and along said second main circuit;
• said shuttle comprising a first check valve and a second check valve respectively arranged in said first passage channel and in said second passage channel, said first check valve comprising at least one first flow control element that can move from an open position, for the passage of said working liquid along said first passage channel and therefore along said first main circuit, to a closure position, for closing said first passage channel and therefore said first main circuit and vice versa, said second check valve comprising at least one second flow control element that can move from an open position, for the passage of said working liquid along said second passage channel and therefore along said second main circuit, to a closure position for the closure of said second passage channel and therefore of said second main circuit and vice versa;
• a first discharge channel and a second discharge channel, for the connection respectively of said first main circuit to said second recirculation circuit, and of said second main circuit to said first recirculation circuit;
• wherein said first check valve and said second check valve respectively are provided with first damping means and second damping means in order to slow down the passage movement respectively of said first flow control element and of said second flow control element from the respective closure position to the respective open position.