Temperature-Compensated Gas Spring With Nested Compensation Cylinder

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Solution Overview

Problem

Existing gas pressure springs exhibit temperature dependence of the spring force, requiring complex designs or larger installation spaces, and often fail to compensate for temperature variations across a wide range effectively.

Innovation Solution

A gas spring design with a working piston in a working cylinder and a compensating cylinder, utilizing a compensating medium like expansion wax and oil, where the compensating piston moves to adjust the working space based on temperature changes, with a sealing device ensuring gas containment and ease of manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compensating medium is used to compensate for temperature dependence, then temperature compensation is achieved, but device complexity increases

Engineering Contradiction:
Improvetemperature compensationVSAvoiddesign complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The compensating cylinder is rigidly attached to the working cylinder, merging two functional components into a single integrated structure. This reduces the number of separate parts and simplifies the overall design while maintaining temperature compensation functionality through the compensating medium.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compensating piston serves multiple functions: it separates the working chamber from the compensating chamber, responds to temperature changes of the compensating medium, and adjusts the working cylinder volume accordingly. This multi-functionality reduces the need for additional components.

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

2Reliability

If a compensating cylinder is added for temperature compensation, then temperature independence is improved, but installation space increases

Engineering Contradiction:
Improvetemperature independenceVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The compensating cylinder is arranged to surround the working cylinder radially, creating a nested configuration. The compensating piston moves within the compensating cylinder while the working piston operates within the working cylinder. This nested arrangement achieves temperature compensation without significantly increasing the overall footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of extending the compensating mechanism along the stroke axis, the compensating cylinder is positioned radially around the working cylinder. This dimensional change allows temperature compensation functionality to be added without increasing the length of the gas spring, thereby minimizing installation space requirements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a compensating piston and compensating medium are used, then temperature compensation is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvetemperature compensationVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The compensating cylinder is rigidly attached to the working cylinder, merging two functional components into a single integrated structure. This reduces the number of separate parts and simplifies the overall design while maintaining temperature compensation functionality through the compensating medium.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compensating medium (expansion wax and oil mixture) automatically responds to temperature changes by expanding or contracting, which automatically moves the compensating piston to adjust the working volume. This self-acting mechanism eliminates the need for external control systems or complex actuation mechanisms.

Inventive Principle:
Principle #25Self-service

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 design provides a cost-effective, simple, and reliable gas spring with temperature-independent spring force over a wide range, minimizing space requirements and reducing manufacturing complexity while maintaining effective temperature compensation.

Implementation Method 1

The annular space formed between the working cylinder and a compensating cylinder is filled with a compensating medium that expands when the temperature rises

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The sealing device preferably seals off the piston rod end to prevent gas from entering or escaping from the working cylinder

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP4370809B1Gas pressure spring with temperature compensation, and method for producing the gas pressure spring
Publication Date: 2025.06.25 STABILUS GMBH
  • EP4370809B1 patent drawingFigure 1
  • EP4370809B1 patent drawingFigure 2~3

AI summary

The invention relates to a gas pressure spring (50), comprising a working piston (2) which is guided displaceably in a working cylinder (1) along a stroke axis (H), a compensating cylinder (12) which encloses the working cylinder (1), and a compensating piston (10) which is of hollow-cylindrical shape and is guided displaceably in the compensating cylinder (12) along the stroke axis (H). The working cylinder (1) has an open end (1b), at which the compensating cylinder (12) forms a projection (15) beyond the working cylinder (1) with a closed end (15b). The compensating piston (10) disconnects a working chamber (1a) which is arranged in the working cylinder (1), a compensating chamber (12a) which is arranged between the working cylinder (1) and the compensating cylinder (12), and a restoring chamber (15a) which is arranged in the projection (15) from one another. A spacing radially with respect to the stroke axis (H) of the compensating cylinder (12) from the working cylinder (1) is greater in the stroke region (HB) than in an end region (EB) of the working cylinder (1), which end region (EB) lies between the stroke region (HB) and the open end (1b) of the working cylinder (1).