In servo control systems, the variable-displacement or servo pump performs the same basic function as the control valve. However, the servo pump generates the controlled fluid power as demanded in response to an input control signal. In most applications, the pump is driven at nearly constant speed by an electric motor or some other mechanical […]
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An expensive hydraulic variable displacement pump offers many options for hydraulic circuit design. The pump displacement can be changed using a servo valve to manipulate the actuator speed movement. The open loop hydraulic design as shown in figure above can be re-design in to a closed loop system by adding sensor on the gearbox output […]
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Variable displacement pump circuits are called demand flow circuits. A simple example is shown in Fig. 4.6. (The astute reader will quickly observe that this circuit is the first circuit we have studied with no relief valve. Although no relief valve is shown, it is recommended that a relief valve always be used to ensure […]
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