Hyundai HX145LCR Manual page 144

②
Accelerating operation Accelerating operation
When VA and VB ports are connected respectively to pump and tank by operating the control
valve, hydraulic oil from pump is forwarded through VA port to push open the check valve
provided inside spool (31), and oil flows to motor via MA port to rotate the motor.
Therefore, the pressure increases and negative brake is released by the pressure supplied from
pump. At the same time, the pressure of pilot chamber increases to push and move the spool
(31) leftwards, overcoming the spring (33) force. Thus, the return line from MB to VB opens to
rotate the motor.
In case inertia load is too big to start rotation, accelerating pressure reaches the set pressure of
relief valve and high pressure oil is being relieved while the motor gains the rotational speed.
As the rotational speed goes up, the relieved volume decreases, and finally the motor rotates at
a fixed speed.
MB MB
VB
DR
MA MA
VA
2-92
DR
MB MA
VB VA
125LCR2TM30