Pressure Limiting Device with Elastic Selector Valves

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Solution Overview

Problem

Existing pressure limiting devices in hydraulic circuits for vehicles are not always satisfactory in controlling pressure and can lead to damage due to overpressure, particularly in cases of wheel slippage, and they often require multiple protective devices, which increase complexity and manufacturing costs.

Innovation Solution

A pressure limiting device with an elastic member between the shutters of selector valves allows simultaneous closure of the valves when pressure on both supply lines exceeds a setpoint threshold, using a single device to improve compactness and reduce costs, integrating the functions of a pressure selector and two limiters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two separate pressure limiters are used to protect both lines, then the hydraulic circuit is protected from overpressure, but the device complexity and manufacturing costs increase

Engineering Contradiction:
Improveoverpressure protectionVSAvoidnumber of protective devices
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines two separate pressure limiters into a single integrated device that protects both high-pressure and low-pressure lines. The device includes a body with two inlet ports (one for each line) and a common outlet port, with two shutters that can be simultaneously actuated by a single elastic member when both lines exceed pressure thresholds, thereby reducing component count while maintaining dual-line protection capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single pressure limiting device performs multiple functions: it protects both the high-pressure line and low-pressure line from overpressure conditions, selects which line to evacuate based on pressure conditions, and provides coordinated response to simultaneous overpressure events through the elastic member mechanism, replacing what would traditionally require two separate dedicated limiters

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

2Reliability

If two pressure limiters are arranged to discharge into each other's lines, then overpressure is managed, but the risk of damage remains in case of simultaneous overpressure on both lines

Engineering Contradiction:
Improveoverpressure managementVSAvoiddamage risk during wheel slippage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The elastic member acts as an intermediary mechanism between the two shutters. When both lines experience overpressure simultaneously (such as during wheel slippage), the elastic member transmits and coordinates the actuation force to both shutters, ensuring they open in response to the overpressure condition and allowing safe evacuation of pressure, thereby eliminating the harmful effect of uncontrolled simultaneous overpressure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The device converts the potentially harmful simultaneous overpressure condition into a controlled evacuation event. The elastic member mechanism ensures that when both lines exceed pressure thresholds, both shutters open to allow pressure relief, transforming the dangerous simultaneous overpressure scenario into a safe, coordinated pressure management response

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 protects hydraulic circuits from overpressure by simultaneously opening the two overpressure valves when both lines are under high pressure, preventing damage and optimizing space and manufacturing costs.

Implementation Method 1

an elastic member (140) inserted between the shutters (162, 182) of the two overpressure valves allows the simultaneous closing of the two valves (132/154 and 134/158) of the selector when the pressure on the two supply lines (11, 12) is simultaneously greater than a setpoint threshold

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3329155B1Pressure limiting device comprising two separate selector valves
Publication Date: 2020.04.15 POCLAIN HYDRAULICS IND
  • EP3329155B1 patent drawingFigure 1~2
  • EP3329155B1 patent drawingFigure 3
  • EP3329155B1 patent drawingFigure 4~5

AI summary

The invention relates to a pressure-limiting device designed to be installed in a system comprising a first line and a second line that can comprise pressurised oil, as well as comprising a discharge and/or booster line. The device also comprises a pressure selector (150) and two pressure relief valves (160, 180). The limiting device is characterised in that the selector (150) comprises two separate valves (152, 156) and a resilient member (140) disposed between the closure members (154, 158) of the two separate selector valves, such that when the working pressure on the first and second lines is below a predetermined threshold, one of the selector valves (152, 156) is open and the other is closed, and when the working pressure on the first and second lines is above the predetermined threshold the two selector valves (152, 156) are closed.