1 large arm lifting operation.
The large arm lifting operation is faster because the oil originally flowed into the oil port P2 is combined, and the housing of the pump P1 is flowed through the oil port P1. This joint is supplied to the top of the large arm cylinder. At low speed operation, only the spool of the large arm 1 operates, and the spool of the large arm 1 is provided by the hydraulic oil of the pump P2.
The hydraulic oil of the pump P2 flows into the spool of the arm 1 through the oil port P2 and the parallel passage. The hydraulic oil of the pump PL flows into the spool of the large arm 2 through the oil port PL and the parallel passage.
In the large arm lifting operation, the pressure of the pilot control valve into the oil port XABL, and the springs 3 of the left large arm 1 move the spring. The hydraulic oil of the pump P2 enters the parallel channel, and then flows through the load check valve LCB1, the large arm 1 spool and the check valve HV re-flowing into the oil port ABL, and then flows into the top end of the large arm cylinder.
At the same time, the pilot pressure of the oil port XAB2 pushes the large arm 2 spool 12 to the left. The hydraulic oil of the pump PL flows through the parallel-channel and central sidewalk 14, and then passes through the load check valve CSP, the large arm 2 spool and the load check valve CCB, and the flow rate is combined into pass and directly flow into the oil port ABL and the arms. The top of the cylinder.
The rod end of the arm cylinder is returned to the spool of the arm 1 through the oil port BBL. Then, the oil port R2 is flowed directly into the passage.
2HYUNDAI excavator drops.
In the process of decline in the arm, the pressure of the pilot lever is supplied to the oil ports XBB1 and BBL, and the large arm 1 spool 3 moves against the inner and outer two springs 7, 8 to the right.
The hydraulic oil of the pump P2 enters the parallel passage through the load check valve LCB1 and flows directly into the oil port BBL, and then flows into the large arm cylinder rod end.
The return flow of the top end of the large arm cylinder flows back to the large arm 1 spool through the oil port ABL, and then passes directly into the return passage R2 through the channel.
In addition, it is limited to the return of oil in the channel to reduce the large arm cylinder in a suitable speed.
