As shown in Figure 2-110, the Hitachi excavator parking brake is controlled by the force of the disc spring and released by the oil pressure. It is installed in the walking motor unit and is controlled by disc springs, pistons, friction plates, plates, etc.
The parking brake is often automatically activated except when walking.
The pressurized oil from the high-pressure side port (AV or BV) flows into the pressure reducing valve through the shuttle valve for brake release. To release the parking brake, reduce the pressure to an appropriate pressure to prevent damage to the seal. The pressure-reduced oil passes through the channel in the motor housing and pushes the piston upward. There is a gap between the friction plates and the plates are released, 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 pressurized oil in the passage is scattered in the motor housing through the throttle of the pressure reducing valve, and the parking brake slowly works.
