SYSTEM / Control System Boom Flow Rate Control Valve Control Purpose: Restricts pressure oil to the boom cylinder from the pump during combined operation of boom lower and arm or boom lower and bucket. When the boom is lowered due to own weight with the regenerative circuit and pressure oil from the pump is used for other actuator, operating speed of actuator in- creases. (Refer to the Control Valve group / COM- PONENT OPERATION.) Operation: 1. When the pressure sensor sends the signal to MC during combined operation of boom lower and arm or boom lower and bucket, MC activates so- lenoid valve unit (SF). 2.
Pressure oil from the pilot pump acts on the switch valve in boom flow rate control valve. 3. Therefore, the switch valve in boom flow rate control valve is shifted and pressure oil which flows to the boom cylinder from the pump is re- stricted. 4. Consequently, pressure oil from the pump flows to the actuator and operating speed of actuator in- creases. T2-2-52