Gas Pressure Spring Rod-Integrated Compensation for Stable Force

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Solution Overview

Problem

Gas pressure springs experience significant temperature-dependent variations in spring force due to thermal expansion and contraction of the gas, leading to inefficiencies and increased wear, particularly in applications like vehicle tailgates, where they need to be stronger at low temperatures and more manageable at high temperatures.

Innovation Solution

The gas pressure spring incorporates a compensation medium arranged partially within the working rod, allowing for temperature compensation without increasing the overall length, with a compensating piston and plunger mechanism that adjusts the volume of the working space to maintain consistent force across temperature changes, simplifying assembly and reducing manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a compensating medium is arranged in an annular space between the working cylinder and a surrounding compensating cylinder, then temperature compensation is achieved, but the overall length of the device increases significantly

Engineering Contradiction:
Improvetemperature compensationVSAvoidoverall length
Core Design Contradiction:
TemperatureVSLength of moving object

Solution Approach 1:

The compensating chamber is integrated within the working rod itself, nesting the temperature compensation function inside the existing structural component. The working rod contains a cavity that houses the compensating medium, eliminating the need for a separate external compensating cylinder and thereby avoiding increased overall length while maintaining temperature compensation capability

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges the compensating chamber with the working rod structure, combining two previously separate functions (working rod and compensating cylinder) into a single integrated component. This reduces the number of parts and eliminates the additional length required by a separate compensating cylinder

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If the compensating chamber is formed by an annular space between the working cylinder and compensating cylinder, then temperature compensation is provided, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvetemperature compensationVSAvoidconstruction complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The compensating chamber is nested within the working rod as an internal cavity rather than being formed by a separate external component. This integration reduces the number of parts that need to be manufactured and assembled, thereby simplifying the overall device construction and reducing manufacturing complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent combines the working rod and compensating cylinder into a single integrated working rod structure with an internal compensating cavity. This merging eliminates the need for separate compensating cylinder manufacturing and assembly operations, reducing device complexity and manufacturing cost

Inventive Principle:
Principle #5Merging (Combining)

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 provides improved temperature compensation with reduced length and weight, lower manufacturing costs, and enhanced operational ease, resulting in a more efficient and durable gas pressure spring system.

Implementation Method 1

a compensating medium arranged in a compensating chamber which expands when the temperature increases

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

at a constant volume V, the gas pressure p increases or decreases (for an ideal gas, p*V = n*R*T)

Methodology Applied
Scientific EffectIdeal gas law:

Data Source

PatentEP4153884B1Gas pressure spring and method for producing the gas pressure spring
Publication Date: 2024.05.22 STABILUS GMBH
  • EP4153884B1 patent drawingFigure 1
  • EP4153884B1 patent drawingFigure 2

AI summary

The invention relates to a gas pressure spring (50), comprising a working cylinder (1), which, together with a slidably mounted compensating piston (10), encloses a working chamber (1a) filled with a working medium (1M). A slidably mounted working piston (2) is fastened to a working rod (6). In the event of a temperature increase, a compensating medium (16M) in a compensating chamber (16) expands. The compensating piston (10) is acted upon by the pressure of the working medium (1M) and by the pressure of the compensating medium (16M) such that the volume of the working chamber (1a) is increased. The temperature dependency of the gas spring force should be reduced by means of a design which is as simple as possible. For this purpose, the compensating chamber (16) is at least partially surrounded by the working rod (6). Thus, the compensating medium (16M) can be compactly accommodated, and the assembly of the gas spring (50) is simplified.