Variable Displacement Pump Pressure Control via Segmented Slide Valves
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Solution Overview
Problem
Existing variable displacement pumps face challenges in maintaining stability and dynamics of pressure control, particularly at high pressures, where they often consume excessive power and risk overheating, while also struggling to independently control quantity and pressure variations.
Innovation Solution
The design incorporates a pressure valve as a slide valve with a pressure control piston and a quantity regulator as a slide valve with multiple control edges, both operating independently to manage differential pressures before and after a hydraulic resistance, allowing for separate optimization of quantity and pressure control, and includes features like adjustable lifting rings and throttles to regulate pressure and volume flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a pressure relief valve design is used, then pressure control is achieved, but stability and dynamics of pressure control deteriorate at high pressures
Solution Approach 1:
The control system is segmented into two independent slide valves: a quantity regulator with a quantity control piston and a pressure valve with a pressure control piston. This segmentation allows separate optimization of quantity control and pressure control, enabling stable pressure control at high pressures while maintaining good dynamics, as each piston can be independently tuned without compromising the other.
2Stress or pressure
If conventional pressure control is used, then pressure regulation is achieved, but power consumption increases and overheating risk occurs
Solution Approach 1:
The pressure control piston is subjected to differential pressure from both before and after the hydraulic resistance, creating a feedback mechanism. This feedback allows the pump to maintain pressure regulation while reducing power consumption by only pumping the necessary amount, avoiding excessive power consumption and overheating risks associated with conventional pressure control methods.
3Device complexity
If quantity and pressure control are combined, then system compactness is achieved, but independent optimization of control quality deteriorates
Solution Approach 1:
The control system is divided into two independent slide valves: a quantity regulator with a quantity control piston having multiple control edges, and a pressure valve with a pressure control piston having a pressure control edge. This segmentation allows independent optimization of quantity control quality and pressure control quality, while both valves can be integrated in a compact arrangement to maintain space efficiency.
4Stress or pressure
If a hydraulic resistance is introduced, then pressure differential control is achieved, but device complexity increases
Solution Approach 1:
A hydraulic resistance (throttle) is introduced as an intermediary element in the delivery line to create a pressure differential. This simple passive element enables the pressure control piston to receive control pressures from both before and after the resistance, achieving sophisticated pressure differential control without significantly increasing device complexity, as the throttle is a straightforward component to integrate.
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 configuration maintains a constant delivery quantity regardless of pump speed and load pressure, reduces power consumption, prevents overheating, and allows for simple variation of volume flow and pressure, while being compact and cost-effective.
Implementation Method 1
a pressure valve with a pressure control piston which has a pressure control edge and is acted upon on a pressure control surface with the pressure which is before or if necessary behind the hydraulic resistance in the high pressure area
Implementation Method 2
a hydraulic resistance in a high pressure area
Implementation Method 3
a quantity regulator which is designed as a slide valve with a quantity control piston having a plurality of control edges and which is subjected to a differential pressure, which prevails before and after a hydraulic resistance
Implementation Method 4
a lifting ring which is adjustable depending on the pressure in a first adjustment pressure chamber and a second adjustment pressure chamber
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a variable displacement pump having a cam ring which can be adjusted as a function of the pressure in a first adjusting pressure chamber and in a second adjusting pressure chamber, and having a flow rate regulator which is designed as a slide valve with a flow rate regulating piston which has a plurality of control edges and which is acted on with a differential pressure prevailing upstream and downstream of a hydraulic resistance, and having a pressure valve. The invention is characterized in that the pressure valve is designed as a slide valve with a pressure regulating piston which has a pressure control edge and which is acted on, on a pressure control surface, with the pressure prevailing upstream or if appropriate downstream of the hydraulic resistance in the high-pressure region.