Hydraulic Distributor Pressure Compensation for Dragging Load Stability

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Solution Overview

Problem

Existing hydraulic distributors face challenges in maintaining optimal flow rate control, especially under dragging loads, which can lead to excessive pressure and instability, damaging components and causing oscillating phenomena.

Innovation Solution

A hydraulic distributor with a pressure compensator positioned to intercept both delivery and discharge branches, using a continuous-positioning spool to adjust flow rates based on working conditions, incorporating four ways to manage pressure and fluid flow, and an energy recovery section for efficient fluid management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pressure compensator is placed on the discharge branch to control flow rate under dragging loads, then flow rate control is improved, but working pressure increases excessively

Engineering Contradiction:
Improveflow rate controlVSAvoidworking pressure
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The patent introduces a controlled oil escape way as an intermediary element between the discharge branch and the compensator. This escape way provides a pressure relief path that prevents excessive pressure buildup while maintaining the compensator's flow control function. The escape way acts as a mediator that balances the conflicting requirements of flow control and pressure limitation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the pressure compensator is placed on the discharge branch, then flow rate control under dragging loads is improved, but system stability deteriorates due to oscillating phenomena

Engineering Contradiction:
Improveflow rate controlVSAvoidsystem stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The controlled oil escape way serves as a stabilizing intermediary that dampens pressure fluctuations and oscillations in the discharge branch. By providing a regulated pressure relief path, it reduces the elasticity effects and distance-related instability between pressure references, thereby improving system stability while preserving flow control capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stress or pressure

If the oil escape way is created to reduce excessive pressure, then pressure control is improved, but flow rate control precision deteriorates

Engineering Contradiction:
Improvepressure controlVSAvoidflow rate control precision
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The oil escape way is designed with controllable opening characteristics that dynamically adjust based on operating conditions. The escape way remains closed during normal operation to maintain flow control precision, and opens selectively when pressure exceeds safe thresholds. This dynamic behavior allows the system to achieve both precise flow control and effective pressure limitation without compromising either function.

Inventive Principle:
Principle #15Dynamics

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 optimizes flow rate control, reduces excessive pressure risks, and stabilizes the hydraulic system, preventing damage and oscillations, while enabling efficient energy recovery and precise adjustment according to operating conditions.

Implementation Method 1

the purpose of pressure compensation is to maintain a constant pressure drop at the ends of the adjustment ports

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

using pressure signals taken on the delivery branch for flow rate control purposes, while compensation takes place on the discharge branch

Methodology Applied
Scientific EffectPressure feedback: Feedback

Data Source

PatentEP4080063B1Hydraulic distributor with pressure compensator for directional valves
Publication Date: 2024.09.04 WALVOIL
  • EP4080063B1 patent drawingFigure 1
  • EP4080063B1 patent drawingFigure 2
  • EP4080063B1 patent drawingFigure 3

AI summary

An hydraulic distributor comprises at least one main spool configured to define a delivery branch, and a discharge branch, a feed branch and a pressure compensator configured such that a local pressure acts on a first side thereof and a maximum Load Sensing pressure acts on a second side characterising either the working pressure of the hydraulic section, in the case in which there is only one hydraulic section, or, in the case in which there is a plurality of hydraulic sections, each one defining a respective characteristic pressure, of the maximum pressure among the characteristic pressures of the hydraulic sections. The pressure compensator is arranged such as to respectively intercept said delivery branch and said discharge branch.