Understanding variable displacement pumps

from Understanding variable displacement pumps

Almost all hydraulic applications use hydraulic pumps. The pump performs the task of converting mechanical energy into hydraulic energy. Take reservoir fluid and transfer it to other system components through pipes. From simple hand pumps to complex piston and gear pumps, you can find many classifications of hydraulic pump. A manual pump requires mechanical force to start the process, while complex pumps use electric motors to actuate hydraulic pumps. Forestry equipment, mining machinery, excavators, dump trucks, cranes, fireworks, loaders, etc. They use hydraulic pump applications.

Positive displacement and non-positive displacement are the two main classifications of hydraulic pumps. Non-positive hydraulic pumps produce a continuous flow and a positive displacement pump produces a constant flow approximate to a constant speed regardless of pressure changes. Here, we will discuss a specific positive displacement pump called variable displacement pump.

A variable displacement pump converts mechanical energy (rotation or engine rotation) into hydraulic energy. However, some variable piston pumps will also perform opposite operations. That is, the conversion of hydraulic energy into mechanical energy (the function of a hydraulic motor). The flow and output pressure of the variable flow pump can be changed during operation. These pumps are commonly used to boost a wide variety of tools. But such bombs are more complex and expensive compared to others.

The construction industry, mining, agriculture, oil and gas industry, and many other industries use variable displacement pump applications. These pumps do not require manual control. The valves that control the speed of the motors will control the fluid flow. Therefore, variable flow pumps are more energetically efficient than fixed flow pumps.

In variable displacement pumps, no heat is generated by moving the oil through the circuit when no work is being done in the actuator. These pumps only produce power when required. In addition, these pumps minimize the use of flow control and pressure control valves.

Piston pumps and plate pumps are two categories of variable displacement pumps. The wide range of volumetric efficiency and pressure of variable displacement pumps make them more popular than plate pumps. More details about these pumps are provided below.

Variable displacement piston pump

High efficiency, high pressure operation and various types of control applicable are the advantages of piston pumps. Pistons, piston or cylinder block, valve plate, piston shoes, rocker plate and driver are the important components of a piston pump. Axial piston pumps, radial piston pumps and inclined shaft piston pumps are the common types of piston pump.

Pumps that convert the rotary motion of the input shaft into an alternating axial motion of the piston are called axial piston pumps. In folded-axis piston pumps, the axis of the cylinder block is bent to produce reciprocal action of the piston. In radial piston pumps, the pistons are aligned radially in the cylinder block.

Variable displacement plate pump

The plate pump has many pallets that slide into the grooves of the rotor and can become a faulty pressure pump that replaces the drive wheel. Defective pressure pumps mean that the pump's operation stops when the pump reaches a certain pressure. For each revolution, variable displacement plate pumps deliver the same fluid volume. Two types of variable displacement plate pumps are direct drive and pilot drive.

Source: Rexroth hydraulic pump

Variable displacement piston pump

Variable displacement plate pump

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Understanding variable displacement pumps