1. Sumitomo excavator rotation speed limit control loop
This control circuit is used to control the slewing speed that increases with the increase in the flow of the hydraulic pump (only in the SP mode).
In the single swing operation, according to the input electrical signal of the swing pilot pressure sensor and the P1 pressure sensor, the signal is output from the controller to the proportional valve for the flow control of the hydraulic pump P1.
The hydraulic oil discharged from the hydraulic pump A3 is distributed to the P flow control proportional valve. The signal output from the controller to the PI flow control proportional valve reduces the hydraulic oil flow on the hydraulic pump A1 side to 200L/min.
①Fully automatic conditions of rotation speed limit control:
①Single swivel full joystick operation;
②Walking is non-operation;
③ Operation mode SP.
Releasing condition of rotation speed limit control:
① When performing upper body operations other than boom lowering → slowly release (to reduce the impact):
②When the walking operation is carried out → release immediately (to avoid snakes);
③When performing standby operation.
2. Rotary overflow cuts off the control circuit
When a single swing operation is suddenly performed, the starting pressure will rise, and the remaining oil will be discharged from the swing motor relief valve. The function of the control circuit is to control the hydraulic pump to minimize the remaining oil discharged, thereby saving energy. Effect.
