Pressurized Medium Assembly for Smooth Load Variation

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Solution Overview

Problem

Digital pressurized medium systems face power loss inefficiencies and oscillating load issues when attempting to produce loads between discrete levels, leading to system instability and potential damage to loaded members.

Innovation Solution

A pressurized medium assembly with a combination of on/off control for one working chamber and proportional regulation for another, allowing for infinite load variation within a sub-range, reducing the risk of oscillating loads by utilizing a proportional pressure control valve and potentially including additional working chambers for discrete load levels with low power losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If digital pressurized medium systems use on/off valves to control pressure levels in working chambers, then power losses are reduced, but the system cannot produce intermediate load levels and may oscillate between discrete load levels

Engineering Contradiction:
Improvepower lossesVSAvoidsystem stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system divides the working chambers into two groups: first working chambers controlled by on/off valves for discrete pressure levels, and second working chambers controlled by proportional valves for continuous pressure adjustment. This segmentation allows the system to combine the energy efficiency of on/off control with the smooth load variation of proportional control, preventing oscillations while maintaining low power losses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different control strategies are applied to different working chambers based on their specific functions. The first working chambers use on/off control suitable for their discrete pressure requirements, while the second working chambers use proportional control to provide intermediate load levels and ensure system stability. This local differentiation of control quality resolves the contradiction between energy efficiency and stability.

Inventive Principle:
Principle #3Local quality

2Device complexity

If digital pressurized medium systems use on/off valves for pressure control, then the control structure is simplified, but the ability to provide continuous load variation is lost

Engineering Contradiction:
Improvecontrol structureVSAvoidload variation capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The control system is segmented into two parts: a simple on/off control section for first working chambers that maintains low complexity, and a proportional control section for second working chambers that provides continuous load variation. This segmentation allows the overall system to achieve both simplified control structure and high adaptability by combining different control approaches in different locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second working chambers with proportional control serve multiple functions: they provide intermediate load levels, enable smooth transition between discrete load levels, and ensure system stability. This multi-functionality compensates for the limited adaptability of the on/off controlled chambers while keeping the overall control structure relatively simple.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2923090B1Pressurized medium assembly
Publication Date: 2021.04.14 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP2923090B1 patent drawingFigure 1
  • EP2923090B1 patent drawingFigure 2
  • EP2923090B1 patent drawingFigure 3

AI summary

The present invention relates to a pressurized medium assembly (10) comprising a first working chamber (14) and a second working chamber (16). The first and second working chambers (14, 16) are adapted to together produce a load. The pressurized medium assembly (10) comprises a first control means being adapted to provide a fluid communication between the first working chamber (14) and a pressure line in an on/off manner. The pressurized medium assembly (10) further comprises a second control means adapted to provide a fluid communication between the second working chamber (16) and a pressure line. The second control means is adapted to proportionally regulate the pressure in the second working chamber (16).