Hydrostatic Axial Piston Machine Passage Openings
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Solution Overview
Problem
Existing hydrostatic axial piston machines face challenges in maximizing throughflow openings and optimizing the charging and evacuation of cylinder bores, leading to reduced efficiency and potential cavitation damage, especially at high altitudes with low ambient pressure.
Innovation Solution
The hydrostatic axial piston machine features a rotatable cylinder drum with passage openings having cross sections with two or four widenings and rounded corners, maximizing the cross-sectional area and minimizing mechanical load, while maintaining a continuous flow profile, which allows for increased rotational speed and reduced cavitation risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the passage openings have a circular cylindrical form with smaller diameter than the cylinder bores, then the manufacturing is simpler, but the throughflow area is reduced and charging/evacuation resistance increases
Solution Approach 1:
The passage openings are designed with rounded corners instead of sharp edges, creating a cross-section that transitions from a simple circular cylindrical form to one with curved boundaries. This curvature optimization enlarges the throughflow area while maintaining manufacturability, as rounded corners are easier to machine than sharp angles and improve fluid flow characteristics by reducing turbulence and resistance during charging and evacuation of the cylinder bores.
2Reliability
If the passage openings are oriented obliquely with respect to the cylinder bores, then the sealing is improved, but the throughflow area is reduced
Solution Approach 1:
The passage openings are oriented obliquely relative to the cylinder bores, introducing an angular dimension to the flow path. This oblique orientation improves sealing performance by ensuring better alignment with the distributor disk openings while the cross-sectional area is compensated through the rounded corner design, which enlarges the effective flow area in the radial direction.
3Productivity
If the nominal rotational speed is increased to improve productivity, then the output increases, but cavitation damage occurs at high altitudes with low ambient pressure
Solution Approach 1:
The cross-sectional geometry of the passage openings is modified with rounded corners to optimize the flow parameters. This geometric parameter change reduces flow resistance and improves the charging and evacuation characteristics of the cylinder bores, allowing the system to operate at higher rotational speeds without causing cavitation damage, even in high altitude environments with low ambient pressure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances throughflow efficiency, enabling the axial piston machine to operate effectively at high altitudes with low ambient pressure, reducing cavitation damage and mechanical stress, and allowing for increased nominal rotational speed.
Implementation Method 1
the respective mouths, arranged at the face surface, of the passage openings have a cross section which has two or four widenings with rounded corners. This means that, at two or four points of the cross section, regions are provided which are widened in relation to a circular cross section and whose boundary sections have minimal radii of curvature, wherein, in between, there may extend boundary sections with a greater radius of curvature (curved in the same direction or in opposite directions) or straight boundary sections. The throughflow openings are thus maximized, and an optimized throughflow during the charging and evacuation of the cylinder bores is permitted.
Data Source
AI summary
A hydrostatic axial piston machine of swashplate type of construction includes a rotatable cylinder drum that has a plurality of cylinder bores, which are arranged approximately axially, formed in the cylinder drum. A piston is inserted into each cylinder bore at one side. At the other side, each cylinder bore is freely connected via a respective passage opening to a face surface of the cylinder drum. The face surface bears against a static distributor disk. The respective mouths arranged at the face surface, or the passage openings as a whole, have a cross section that has two or four widenings with rounded corners so as to enlarge the cross-sectional area in relation to the circular shape.