Hydraulic Axial Piston Unit With Adjustable Bypass Control
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Solution Overview
Problem
Existing hydraulic axial piston units have complex control systems that are costly, bulky, and require specific adaptations for each application, leading to high maintenance needs and inefficiencies due to pressure peaks and cavitation issues.
Innovation Solution
A hydraulic axial piston unit with a simplified control system using bypass lines and adjustable orifices to control the displacement volume, reducing the number of components and enabling adaptable operation across different units without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual, hydraulic or electronic control units with servo pistons and control spools are used to set the tilt angle of the displacement element, then the displacement volume can be controlled, but the control system becomes complex, bulky, and costly with high maintenance needs
Solution Approach 1:
The patent extracts and eliminates the complex control spool, servo pistons, and valve plates from the control system. Instead, it uses a simplified arrangement where a piston directly acts on the displacement element (swashplate or bent axis mechanism) to control the tilt angle and thus the displacement volume, removing unnecessary intermediary components
Solution Approach 2:
The patent designs the control system to be application-independent and reusable across different hydraulic axial piston units of various sizes. The control mechanism can be adapted to different displacements and applications without requiring specific customization of control parts, making it a universal solution
2Manufacturing precision
If control and servo units with multiple parts are used to control displacement volume, then precise control is achieved, but the overall size of the hydraulic unit increases
Solution Approach 1:
The patent merges the control function directly into the existing piston-cylinder arrangement. The piston that controls the tilt angle of the displacement element is integrated with the hydraulic circuitry, eliminating the need for separate control units and reducing overall space requirements while maintaining precise displacement control
3Manufacturing precision
If specific valve plates and servo spools with narrow tolerances are used for specific applications, then control precision is improved, but manufacturing cost and installation work increase
Solution Approach 1:
The patent designs control components with broader tolerance ranges that can be used across multiple applications and different sized hydraulic units. The control mechanism does not require application-specific customization, reducing manufacturing complexity and cost while maintaining adequate control precision for various displacements
4Manufacturing precision
If traditional control components are used, then displacement control is achieved, but the components are prone to wear and require continuous maintenance or replacement
Solution Approach 1:
The patent removes the wear-prone control spools and valve plates from the system. By using a direct piston-action mechanism on the displacement element without sliding spools or complex valve arrangements, the design eliminates components that are typically subject to wear and require frequent maintenance
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
The solution provides a more efficient, compact, and cost-effective control system that minimizes pressure peaks and cavitation, enhancing the hydraulic unit's performance and extending its lifespan.
Implementation Method 1
A piston is provided in a cylinder bore with a piston surface area arranged facing away from the valve segment. The circumferential distance from the IDC control port to the first and second pressure ports and the circumferential distance from the ODC control port to the first and second pressure ports is smaller than the circumferential extension of the cylinder bores.
Implementation Method 2
adjusting an opening size of at least one variable orifice arranged in one or in both bypass lines in order to control a pressure level present at the control ports
Implementation Method 3
In order to transform mechanical power into hydraulic power and vice versa hydraulic axial piston units comprise a rotational group. When the displacement element is inclined with respect to the drive shaft axis of the hydraulic unit, the working pistons are forced to reciprocate between their inner dead centre (IDC) and their outer dead centre (ODC)
Data Source
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AI summary
Hydraulic axial piston unit comprising a rotatable cylinder block and a valve segment with two pressure ports. An IDC control port and an ODC control port are located on the valve segment in circumferential direction between the circumferential ends of the pressure ports such that a cylinder bore can be fluidly connected to the IDC control port or the ODC control port when the associated working piston is at or close to its inner dead center or outer dead center. The circumferential distance from the control ports to the pressure ports is smaller than the circumferential extension of the cylinder bores. A first and a second bypass line each connecting one of the control ports are provided with an adjustable orifice in the first bypass line, capable of continuously variably opening and closing the first bypass line in order to enable an adjustable fluid flow connection between the connected pressure port and the connected pressure port.