Hydraulic Pump Charging Valve for Pulsation Damping

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Solution Overview

Problem

Existing hydraulic arrangements with pumps experience volume flow and pressure pulsations, which can lead to mechanical and acoustic vibrations, and disrupt the hydraulic behavior, especially in mobile applications like agricultural and construction machines.

Innovation Solution

A hydraulic arrangement with an adjustable pump, a storage unit, and a charging valve unit that acts as a separable hydraulic connection between the pump and the storage unit, allowing for active damping of pulsations and independent response behavior across different operating ranges, reducing vibrations and pressure pulsations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a storage unit is connected to the pump to reduce pressure pulsations, then pressure pulsations and vibrations are reduced, but the hydraulic behavior is influenced and system rigidity is reduced

Engineering Contradiction:
Improvepressure pulsationsVSAvoidhydraulic behavior
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The charging valve unit dynamically switches between open and closed states based on pump delivery rate, allowing the storage unit to be selectively connected or disconnected from the hydraulic system. This dynamic configuration enables the system to adapt its hydraulic characteristics to different operating conditions, reducing pressure pulsations when needed while maintaining system rigidity when required

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the storage unit is continuously connected to the pump, then pressure pulsations are reduced, but acoustic and mechanical vibrations are increased

Engineering Contradiction:
Improvepressure pulsationsVSAvoidvibrations
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The charging valve unit operates periodically by switching between open and closed states based on pump delivery rate thresholds. This periodic action allows the storage unit to alternately absorb pressure pulsations and remain disconnected, preventing continuous vibration excitation while still providing pulsation reduction during appropriate operating phases

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If the pump operates from full delivery to zero delivery, then flow rate adjustment is achieved, but pressure pulsations and response behavior changes occur

Engineering Contradiction:
Improveflow rate adjustmentVSAvoidresponse behavior
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The charging valve unit dynamically adjusts its state based on pump delivery rate, switching between connected and disconnected configurations to optimize system response behavior across different operating ranges. This dynamic adaptation ensures reliable and consistent hydraulic response regardless of whether the pump operates at full delivery or reduced flow rates

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

The solution effectively reduces or eliminates pressure pulsations, mechanical, and acoustic vibrations, providing a stable hydraulic behavior similar to a system without an accumulator unit, enhancing the efficiency and reliability of hydraulic systems in mobile applications.

Implementation Method 1

a storage unit (e.g. diaphragm storage) which is hydraulically connected to the pump on the output side. This storage unit reduces any pressure pulsations and associated stresses on components

Methodology Applied
Scientific EffectHydraulic connection:

Implementation Method 2

The check valve is closed in the direction of the storage unit

Methodology Applied
Scientific EffectNon-return valve mechanism: Valve

Data Source

PatentEP3462028B1Hydraulic arrangement
Publication Date: 2021.09.15 DEERE & CO
  • EP3462028B1 patent drawingFigure 1

AI summary

The invention relates to a hydraulic arrangement (10) with a pump (12) for conveying a hydraulic medium towards a hydraulic working load (14). The pump (12) has an adjustable inlet (20) for adjusting the pump's flow rate. A storage unit (30) is hydraulically connected to the pump's output side. A charging valve unit (36) is hydraulically connected to the pump's output side between the pump (12) and the storage unit (30) and acts as a separable hydraulic connection between the pump (12) and the storage unit (30).