Hydrostatic Cylinder With Ring Accumulator for Constant Pressure

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Solution Overview

Problem

Hydraulic or hydrostatic cylinders with integrated gas pressure accumulators are not suitable for small permissible pressure ranges due to clamped gas issues, which limits their effectiveness in maintaining constant pressure.

Innovation Solution

A cylinder with a ring-shaped gas pressure accumulator on its outer circumference, where a gas space is separated from a pressure medium space by an elastic or movable separating element, connected to a constant pressure source, ensuring constant pressure even when pressure medium is released, with a check valve and adjustable spring for maintaining gas tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a gas pressure accumulator with clamped gas is used in a hydraulic cylinder, then the cylinder achieves compact design and integrated pressure storage, but the system becomes unsuitable for small permissible pressure ranges due to gas compression issues

Engineering Contradiction:
Improvecompact designVSAvoidsuitability for small pressure ranges
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The gas pressure accumulator is divided into two independent chambers: a gas chamber and a pressure medium chamber, separated by a piston. This segmentation allows the gas and pressure medium to be independently controlled, enabling the system to handle small pressure ranges effectively while maintaining compact design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A piston is introduced as an intermediary element between the gas chamber and pressure medium chamber. The piston transmits pressure from the gas to the pressure medium while preventing direct mixing, thereby enabling precise pressure control in small pressure ranges and improving system reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If gas is compressed in the gas pressure accumulator to store energy, then pressure storage is achieved, but complex gas compression calculations are required

Engineering Contradiction:
Improvepressure storage capabilityVSAvoidgas compression calculations
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The constant pressure source automatically maintains the required gas pressure in the gas chamber without requiring external calculations or adjustments. The system self-regulates the pressure, eliminating the need for complex gas compression calculations while maintaining pressure storage capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The mechanical gas compression process is replaced by a constant pressure source that automatically maintains gas pressure. This substitution eliminates the need for manual gas compression calculations and simplifies the system while preserving pressure storage functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stress or pressure

If pressure medium is released from the pressure medium chamber, then the accumulator maintains pressure, but gas may be lost from the gas chamber

Engineering Contradiction:
Improveconstant pressure maintenanceVSAvoidgas loss
Core Design Contradiction:
Stress or pressureVSLoss of substance

Solution Approach 1:

The piston extracts and isolates the gas chamber from the pressure medium chamber, preventing gas loss when pressure medium is released. The piston acts as a barrier that allows pressure maintenance while preventing substance loss, thereby improving system reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 provides a compact design suitable for small pressure ranges with constant pressure, improved dynamics, no loss of active medium, and simplified gas pressure storage without the need for gas compression calculations, enhancing the cylinder's performance in hydraulic systems.

Implementation Method 1

a gas space (12) is separated from a pressure medium space (14) by means of an elastic or movable separating element (8)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the gas chamber (12) is connected to a constant-pressure source. This achieves the above-mentioned object because the gas pressure accumulator maintains a constant, or within limits, constant pressure in its pressurized fluid chamber even when pressurized fluid is released from the pressurized fluid chamber, whereby the volume of the gas chamber increases

Methodology Applied
Scientific EffectGas compression: Compression

Implementation Method 3

it is preferred if a check valve is arranged between the constant pressure source and an inlet, which closes from the inlet to the constant pressure source

Methodology Applied
Scientific EffectValve closure: Valve

Data Source

PatentEP4048903B1Arrangement comprising as hydrostatic cylinder with gas pressure accumulator
Publication Date: 2024.08.28 ROBERT BOSCH GMBH
  • EP4048903B1 patent drawingFigure 1~2

AI summary

The invention relates to a hydrostatic cylinder with a gas pressure accumulator, which is preferably designed as a piston accumulator, and which is arranged concentrically on the outer circumference of the cylinder. According to the invention, a gas pressure that is limited or is essentially constant in the gas pressure accumulator and and also a constant pressure medium pressure that is independent of the degree of filling of the gas pressure accumulator is produced via a constant pressure source.