Hydrostatic Machine Control Device Using Return Element
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Solution Overview
Problem
Hydrostatic machines face wear and material fatigue issues in their control systems due to extreme loading on mechanical stop regions during quick pivoting actions, leading to impaired operation and displacement volume changes.
Innovation Solution
A control device with a return element and regulating valve system that prevents hard stopping by controlling the control pressure, using an additional valve unit to counteract further adjustments when maximum or minimum displacement volumes are reached, and employing a displaceable valve piston and radially tapered section to achieve hydraulic limitation of the minimum delivery volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical stop regions are used to limit displacement volume, then displacement volume control is achieved, but wear and material fatigue occur in the control components
Solution Approach 1:
The patent replaces the mechanical stop region with a hydraulic control system. A return element (control piston) and regulating valve are used to control the control pressure that limits the displacement volume. This substitutes the mechanical limitation system with a hydraulic one, eliminating direct mechanical contact and wear at the stop regions.
Solution Approach 2:
The patent introduces a control pressure as an intermediary to limit displacement volume. Instead of direct mechanical stops, the control pressure generated by the return element and regulating valve system acts as a mediator to prevent the control piston from reaching positions that would cause mechanical stopping, thereby eliminating wear.
2Reliability
If mechanical stops are used for displacement limitation, then displacement volume is controlled, but hard stopping occurs during quick pivoting actions
Solution Approach 1:
The patent replaces mechanical stop regions with a hydraulic control system using a return element and regulating valve. This substitution eliminates hard mechanical stopping by using fluid pressure control, which can accommodate quick pivoting actions without concentrating impact loads on mechanical components.
Solution Approach 2:
The hydraulic control system provides beforehand cushioning by continuously regulating the control pressure. The return element and regulating valve work together to maintain appropriate pressure levels that prevent sudden hard stops, cushioning the control piston against abrupt mechanical impacts during quick pivoting actions.
3Adaptability or versatility
If mechanical stop regions are used, then minimum and maximum displacement volumes are fixed, but the components become worn and operational quality deteriorates
Solution Approach 1:
The patent replaces the mechanical stop region system with a hydraulic control system. The return element (control piston) and regulating valve together control the displacement volume through pressure regulation, eliminating the mechanical stops that cause wear and operational degradation while maintaining the full adjustment range.
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 solution effectively prevents wear-related issues by maintaining displacement volume stability and ensuring smooth operation without hard mechanical stopping, enhancing the longevity and performance of hydrostatic machine components.
Implementation Method 1
The return element and the regulating valve co-operate to control a control pressure of the control device. The mechanical co-operation of the return element and the regulating valve adjusts a control pressure acting in the control device.
Implementation Method 2
A radially tapered section is formed on the valve piston and forms an annular gap with the valve sleeve. The pressure medium can flow off via this annular gap towards the contact point between the arm of the control sleeve and the valve piston into a housing tank.
Data Source
AI summary
A hydrostatic machine having an actuating device for adjusting a displacement volume of the hydrostatic machine is provided. The actuating device has a return element for actuating a control valve as a function of a position of the actuating device. A valve unit is further provided for adjusting an actuating pressure of the actuating device, which is activated mechanically by means of the return element.