The slewing motor of the Kato excavator is driven by the spool 2 of the control valve (valve block A). The pressure of the oil circuit is adjusted by the overflow valve in the swing motor. When the swing motor is in neutral, the swing motor stops: when the swing joystick moves left and right, the swing motor moves forward or backward, causing the upper turntable to rotate left and right respectively.
The overflow valve plays a role of damping, the supplementary valve prevents cavitation, and the balance (one-way) valve prevents the upper turntable from rotating when it stops. All the above valves are installed in the machine housing on the motor.
(1) Rotation priority oil circuit
When the swing and the forearm excavation operation are working at the same time, the oil circuit gives priority to the oil supply to the swing motor.
The pressure oil of pump A2 flows into the arm II through the central bypass pipe of the control valve (valve block B). The pressure oil of the pump A1 flows through the rotary spool and the small arm spool of the control valve (valve block A), but the pilot pressure acting on the small arm I spool limits its stroke and shortens the stroke of the entire small arm I spool. . By shortening the oil path, sufficient pressure can be maintained to drive the rotary motor.
(2) Swing parking brake
When the joystick is in neutral, the turning stop brake works, and the walking joystick is operated so that the pilot pressure passes through the solenoid valve block to release the brake.
