Cage Pressure Selector for Hydraulic Overpressure Protection

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Solution Overview

Problem

Existing pressure limiting devices in hydraulic assistance circuits for vehicles are not always satisfactory in controlling pressure and can lead to damage due to overpressure, especially in cases of wheel slippage, and they require multiple components increasing manufacturing costs and space usage.

Innovation Solution

A pressure limiting device with a cage-shaped selector and independently adjustable pressure relief valves, which automatically opens one valve when the other is closed, allowing for compact and cost-effective pressure control by connecting the line with the lowest pressure to the booster device, thereby preventing overpressure damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple pressure limiters are used to protect both lines, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvepressure protectionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple pressure limiters into a single integrated device with a common body housing multiple relief valves. This merging approach maintains the protective function for both high-pressure and low-pressure lines while reducing the overall number of separate components, thereby improving reliability without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure limiting device is designed as a multi-functional component that simultaneously protects both the high-pressure line and low-pressure line. The single device incorporates multiple relief valves that can independently respond to overpressure conditions in different lines, providing universal protection across the entire hydraulic system.

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

2Reliability

If pressure limiters are arranged in parallel with the booster pump, then reliability is improved, but volume increases

Engineering Contradiction:
Improveoverpressure protectionVSAvoiddevice space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The pressure limiting device is designed with a compact nested structure where multiple relief valves are housed within a common body that integrates with the booster pump assembly. This nesting arrangement allows the pressure protection functionality to be embedded within the existing pump volume, providing overpressure protection without significantly increasing the overall device space.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If independent adjustment of each relief valve is enabled, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvepressure calibrationVSAvoidadjustment mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The device incorporates local adjustment mechanisms for each relief valve, allowing independent pressure calibration for the high-pressure line and low-pressure line. Each valve has its own adjustment feature located at the valve level, enabling localized pressure setting without affecting other parts of the system, thus providing adaptability with minimal added complexity.

Inventive Principle:
Principle #3Local quality

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 manages pressure by automatically opening both overpressure valves in case of simultaneous overpressure on both lines, reducing the risk of damage to hydraulic machines and optimizing space and manufacturing costs.

Implementation Method 1

connecting the line with the lowest pressure to the booster device

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

automatically opens one valve when the other is closed, allowing for compact and cost-effective pressure control

Methodology Applied
Scientific EffectOverpressure valve opening: Pressure Gradient

Data Source

PatentEP3329154B1Pressure limiting device, in particular for an assist system for vehicles
Publication Date: 2020.02.12 POCLAIN HYDRAULICS IND
  • EP3329154B1 patent drawingFigure 1~2
  • EP3329154B1 patent drawingFigure 3
  • EP3329154B1 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 (11) and a second line (12) that can comprise pressurised oil, as well as comprising a discharge and/or booster line (10). The device also comprises a pressure selector (130, 150) in the form of a cage defining two seats (132, 134) and two pressure relief valves (160, 180). The limiting device is characterised in that it further comprises at least one means (170, 172; 190, 192) for regulating a pressure relief valve, disposed on the outside of an axial end of the pressure selector (150), in the form of a cage that allows the loading of the associated pressure relief valve to be regulated.