Closing and Opening
Closed
1. A closed hydraulic circuit (closed circuit) is formed by an actuator (motor) and a pump.
2,The speed and direction of the actuator are determined by making the angle of the pump's swash plate (please refer to the basic structure)
3, Smooth starting and stopping of the actuator can be obtained in the closed circuit is characterized
4. The pump and motor can be compactly configured as a single unit in a box.
Opening
1. The pump sucks oil from the tank and returns oil from the actuator to the tank, and the circuit is open.
2, in the case of a fixed pump, the speed and direction of the actuator is controlled by the switching of the control valve closed pool opening. In addition, the pump is variable, the pump can also be adjusted flow, but the pump ramp angle changes only to the +a direction.
3. open circuit, can be connected with a - a pump and control multiple actuators.
[VARIABLE VOLUME] When the pump pushes the volume (swash plate angle) variable control, it is controlled by external operation. (In a closed circuit, positive and negative discharge)
●Guide controls the swash plate angle by lever link. <Regulator> The regulator that controls the swash plate angle of the open circuit pump has the following functions. Horsepower control In order not to exceed the engine horsepower, the swash plate angle (pump pressure volume) is changed according to the control discharge pressure so that the maximum value of the pumping torque is constant and the pump consumption horsepower is constant. It is a control that can be effectively utilized to avoid stalling when the consumption horsepower of the pump exceeds the horsepower of the engine.
Load sensing control: This is a control that allows only the necessary flow rate to be discharged according to the operating volume. This control allows the pump to discharge only the pressure and flow rate required by the actuator. In the above illustration of the open circuit (open), in order to keep the pressure difference between the front and rear of the control valve constant, the angle of the pump's swash plate (pushed open volume) is changed to control only the flow rate that corresponds to the opening of the control valve. As a result, there is no residual flow, and an energy-saving system can be realized by suppressing heat generation.
Tandem pumps (2- or 3-connected)1 are designed to rotate 2 or 3 pumps with a single input shaft. Since the flow rate can be supplied independently from the 1st and 2nd pumps, for example, by supplying the driving motor, it is possible to constitute a driving system for a vehicle. The third pump can also be used as a charging pump in the case of a closed circuit. [Single flow and split flow] Like the basic structure of a piston pump, the single flow type with one suction port and one discharge port is a normal pump. In contrast, the split-flow type makes it possible to discharge two systems independently of each other by alternating ports on a cylinder block.