Hydrostatic Piston Adjustment Device Spring Feedback Mechanism
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Solution Overview
Problem
Existing hydrostatic axial piston machines have complex and lengthy adjustment devices due to the need for a spring rod that extends through the regulating piston, complicating the apparatus and increasing structural length.
Innovation Solution
An adjustment device with an adjustment piston, regulation valve, and feedback springs that exert forces dependent on the piston's position, allowing for torque regulation with a reduced apparatus outlay and shorter structural length by eliminating the spring rod, and enabling a hyperbolic characteristic curve between operating pressure and swept volume with a bend between two straight sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring rod extends through the regulating piston to provide feedback force, then the torque regulation function is achieved, but the device complexity and structural length increase
Solution Approach 1:
The patent extracts and eliminates the spring rod component from the adjustment device. Instead of using a spring rod that extends through the regulating piston, the invention uses feedback springs that act directly on the valve slide, removing the unnecessary intermediate component while maintaining the torque regulation function.
Solution Approach 2:
The patent introduces a bushing as an intermediary component that is driven by the adjustment piston and acts on the valve slide. This bushing serves as the feedback mechanism, replacing the spring rod and providing the necessary mechanical coupling between the adjustment piston and valve slide without adding structural complexity.
2Reliability
If a spring rod extends through the regulating piston to provide feedback force, then the torque regulation function is achieved, but the structural length increases
Solution Approach 1:
The patent removes the spring rod component that would extend through the regulating piston, thereby reducing the overall structural length of the adjustment device while maintaining the essential torque regulation function through alternative feedback spring arrangements.
Solution Approach 2:
The patent changes the arrangement from a linear extension through the piston to a compact feedback spring configuration that acts laterally on the valve slide, reducing the axial length requirement while maintaining the feedback function.
3Measurement precision
If multiple feedback springs are used to create a hyperbolic characteristic curve, then the torque regulation precision is improved, but the device complexity increases
Solution Approach 1:
The patent uses two feedback springs with different characteristics that engage at different positions of the adjustment piston. The first feedback spring acts over the entire travel, while the second feedback spring engages only after a particular partial stroke, creating a dynamic system that approximates a hyperbolic characteristic curve through staged spring engagement.
Solution Approach 2:
The patent employs a second feedback spring that provides partial action only over a specific portion of the adjustment piston's travel. This second spring engages after a particular partial stroke to provide the additional force needed to approximate the hyperbolic curve, rather than requiring a complex continuous spring system.
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 allows for compact and efficient power/torque regulation in hydrostatic piston machines, reducing the structural complexity and length of the adjustment device while maintaining effective control over the swept volume and pressure, with the ability to adjust the torque characteristic curve.
Implementation Method 1
a first feedback spring and a second feedback spring which exert on the valve slide a feedback force which is dependent on the position of the adjustment piston
Implementation Method 2
pressure medium flows into the adjustment chamber or out of the adjustment chamber
Data Source
AI summary
An adjustment device for regulating the torque of a hydrostatic piston machine with adjustable swept volume, comprises an adjustment piston delimiting an adjustment chamber, a regulation valve defining a valve bore and including a valve slide positioned in the valve bore that controls inflow and outflow of pressure medium, and first and second feedback springs configured to exert feedback force on the valve slide in first and second displacement directions dependent on a position of the adjustment piston. The device further includes a regulation spring configured to exert a force on the valve slide in a second displacement direction. During an adjustment of the adjustment piston in a direction of maximum swept volume of the piston machine, beyond a particular position of the adjustment piston, the first and second feedback springs exert an increased force on the valve slide determined only by a spring constant of the first feedback spring.