Axial Piston Motors - high speed, high pressure
Axial piston motors from LöSi - Bent axis and Swashplate design
What types of axial piston motors are there?
There are two main types of axial piston motors:
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Bent-axis design: In this design, the cylinder block and the drive shaft are inclined at a certain angle, allowing the direct transfer of piston movement to the shaft. The bent-axis design is characterized by high efficiency and compactness and is often used in applications where smooth and continuous operation is required.
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Swashplate design: In this design, the cylinder block remains parallel to the drive shaft, while the piston movement is controlled by an inclined plate, the so-called swashplate. This design offers flexible displacement control and is well-suited for applications requiring variable speeds and displacement volumes.
Axial piston motor operation
The operation or structure of an axial piston motor can be described as follows:
Basic structure
The axial piston motor consists mainly of a cylinder block, several pistons, a drive shaft, and either a bent-axis or a swashplate, depending on the design.
- Cylinder block: Contains multiple cylinders in which the pistons move. The cylinder block rotates along with the drive shaft.
- Pistons: Several pistons are arranged in the cylinders of the cylinder block. These are moved by the pressure of the hydraulic fluid.
- Bent-axis or swashplate: In the bent-axis design, the cylinder block is inclined at an angle to the drive shaft, while in the swashplate design, an inclined plate is responsible for the movement of the pistons.
Operation
The basic idea behind an axial piston motor is the conversion of hydraulic energy into mechanical rotation.
The hydraulic fluid is directed into the cylinders of the cylinder block. This fluid exerts pressure on the pistons, pushing them forward in an axial direction (parallel to the drive shaft).
Due to the inclination of the cylinder block (in bent-axis motors) or the movement of the swashplate (in swashplate motors), the piston movements are converted into a rotational movement of the drive shaft. The pressure of the hydraulic fluid thus causes not only linear motion but, due to the inclination, also the rotation of the entire cylinder block.
As the pistons move, the rotational motion is transferred to the drive shaft.
Return stroke
After the hydraulic fluid has exerted its pressure on the pistons, it exits the cylinder block through the return port and flows back into the hydraulic system. The pistons are returned to their initial position by the cycle of the hydraulic fluid, and the process starts again.
Variable displacement
Some axial piston motors can adjust their displacement. This means that the amount of hydraulic fluid moved per revolution can be changed. This is achieved by varying the angle of the bent-axis or swashplate. A greater tilt results in higher displacement, while a smaller tilt increases displacement and therefore the rotational speed.
Applications of axial piston motors
This type of hydraulic motor is used in, for example, construction machinery, agricultural machinery, and industrial applications.
Construction machinery
In excavators, wheel loaders, cranes, and other heavy construction equipment, these hydraulic motors are used to control the hydraulic drive of lifting mechanisms, drive mechanisms (such as travel drives in combination with planetary gears), and other hydraulically operated components.
Agricultural machinery
Axial motors are used in tractors, combine harvesters, and other agricultural equipment. They provide power for attachments or conveyor belts, for example.
Industrial applications
Such motors are also used in industrial production machinery, such as presses, rolling mills, or metalworking machines. They provide precise control and high performance with variable loads.