Adjustable Gas Spring with Nested Chambers and Valve

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Solution Overview

Problem

Conventional gas pressure springs lack adjustability in piston rod stroke, limiting their application in scenarios requiring variable movement according to specific criteria.

Innovation Solution

A gas pressure spring design featuring a first and second hollow chamber with a movable piston and a valve device for locking and releasing the second piston, allowing adjustable stroke by fluidly connecting or disconnecting the chamber volumes, enabling variable piston rod movement through a pneumatically actuated valve system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional gas pressure spring with a fixed chamber design is used, then the structure is simple and reliable, but the piston rod stroke cannot be adjusted

Engineering Contradiction:
Improvestroke adjustabilityVSAvoidchamber structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The single chamber is divided into two separate hollow chambers (first hollow chamber and second hollow chamber), each capable of independently containing the piston rod at different positions. This segmentation allows the piston rod stroke to be adjusted by selecting which chamber is active, providing adaptability while keeping each individual chamber structurally simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second hollow chamber is arranged inside the first hollow chamber, creating a nested configuration. This nesting allows both chambers to coexist within the same overall structure without significantly increasing the external dimensions, enabling stroke adjustment while maintaining a compact and relatively simple overall device structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If a locking mechanism for the piston is added to enable stroke adjustment, then the adaptability improves, but the device complexity increases

Engineering Contradiction:
Improvestroke adjustabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A valve device is introduced to control the fluid communication between the first and second hollow chambers. By using pneumatic or hydraulic pressure differential, the valve automatically locks the piston rod at specific positions when chambers are isolated, or allows free movement when chambers are connected. This eliminates the need for complex mechanical locking mechanisms while achieving the same stroke adjustment functionality.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Adaptability or versatility

If multiple hollow chambers are introduced for stroke adjustment, then the adaptability increases, but the manufacturing complexity increases

Engineering Contradiction:
Improvestroke adjustabilityVSAvoidchamber manufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The second hollow chamber is nested within the first hollow chamber, which simplifies the manufacturing process compared to creating two separate external chambers. The nested configuration allows both chambers to be formed as integrated components during a single manufacturing cycle, reducing assembly steps and overall manufacturing complexity while still providing the required stroke adjustment capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables adjustable stroke of the gas pressure spring according to predetermined parameters, enhancing its applicability by allowing precise adjustment of the piston rod's movement range without structural changes to the external area.

Implementation Method 1

the valve device is designed to fluidly connect and separate the first chamber volume V1 and the second chamber volume V2

Methodology Applied
Scientific EffectFluid connection:

Implementation Method 2

The first chamber volume V1 and the second chamber volume V2 are filled with a pressure medium, preferably with nitrogen

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Data Source

PatentEP3336376B1Gas spring
Publication Date: 2020.02.12 ROBERT BOSCH GMBH
  • EP3336376B1 patent drawingFigure 1~2
  • EP3336376B1 patent drawingFigure 3~4
  • EP3336376B1 patent drawingFigure 5

AI summary

The invention relates to a gas spring (1) with a second piston (16) movably arranged between a first axial end section (10a) and a first piston (14) in a first hollow chamber (10) or a second hollow chamber (15), and with means (18) for locking and releasing the second piston (16) for adjusting the stroke of the first piston rod (12). The invention further relates to a method for operating the gas spring (1).