The parking brake of the Hitachi excavator is controlled by the power of the disc spring and released by the oil pressure. It is installed in the unit of the walking motor and is controlled by disc springs, pistons, friction plates, plates, etc.
The parking brake can often act automatically except when walking.
The pressure oil from the high-pressure side port (AV or BV) flows into the pressure reducing valve through the shuttle valve for brake release. In order to release the parking brake, reduce the pressure to an appropriate pressure to prevent damage to the seal. The decompression oil passes through the passage in the motor housing to push the piston upward. A gap is created between the friction plate and the plate to become a released state, and the parking brake is also released.
When stopping walking, the piston is pushed back to the right by the force of the disc spring. The pressure oil in the passage diffuses in the motor housing through the orifice of the pressure reducing valve, and the parking brake works slowly.
