External Bypass Damper for Orientation-Independent Damping

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Solution Overview

Problem

Existing hydraulic dampers require specific orientations and complex piston designs to prevent gas accumulation and foaming, limiting their versatility and applicability across various movement speeds and orientations.

Innovation Solution

A damper design featuring a pressure tube filled with damping fluid, a piston dividing the tube into chambers, and a bypass outside the tube connecting the chambers, utilizing an elastically deformable bypass wall to accommodate fluid volume changes without gas, allowing orientation-independent operation and wide speed range damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a double tube pressure tube design with compressible gas is used to allow piston rod retraction, then the damper can accommodate volume changes, but gas accumulates in the front chamber causing hydraulic oil to foam which impairs the damping effect

Engineering Contradiction:
Improveorientation independenceVSAvoiddamping effect
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The harmful compressible gas is extracted and removed from the pressure tube system entirely. The invention replaces the gas-filled double tube design with a single tube completely filled with incompressible hydraulic oil, eliminating the source of foaming and damping impairment while maintaining volume compensation through the elastic bypass wall

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the physical state parameter of the compensation mechanism from compressible gas to incompressible liquid (hydraulic oil), while introducing an elastic bypass wall that deforms to accommodate volume changes. This parameter change eliminates gas accumulation and foaming while maintaining the necessary compliance for piston rod movement

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a bypass inside the pressure tube is implemented to allow hydraulic oil flow between chambers, then fluid communication is achieved, but the piston design becomes complex and locking mechanism implementation becomes difficult

Engineering Contradiction:
Improvepiston design simplicityVSAvoidbypass structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The bypass is relocated from the internal one-dimensional path within the pressure tube to an external three-dimensional arrangement. The bypass channel now runs outside the pressure tube, connecting the front and rear chambers through an external elastic bypass wall, simplifying the piston design and enabling easier implementation of locking mechanisms

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

Solution Approach 2:

Instead of placing the bypass inside the pressure tube as in conventional designs, the invention inverts the arrangement by placing the bypass outside the pressure tube. This inversion simplifies the internal piston structure and facilitates the integration of locking mechanisms while maintaining the essential function of fluid communication between chambers

Inventive Principle:
Principle #13The other way round (Inversion)

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 damper achieves versatile operation across orientations and speed ranges without gas accumulation or foaming, simplifying construction and enabling effective damping without additional components or complex piston designs.

Implementation Method 1

the bypass being at least partially bounded by a bypass wall, the bypass wall being elastically deformable to receive a volume of damping fluid displaced by the piston rod when the piston rod is inserted into the pressure tube

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4675124A1Damper with bypass, method for producing said damper
Publication Date: 2026.01.07 STABILUS GMBH
  • EP4675124A1 patent drawingFigure 1
  • EP4675124A1 patent drawingFigure 2
  • EP4675124A1 patent drawingFigure 3A~3B

AI summary

The invention relates to a damper (100) comprising a pressure tube (110) filled with a damping fluid; a piston (120) slidably mounted in the pressure tube (110) along a stroke axis (H), wherein the piston (120) divides the pressure tube (110) into a front chamber (111) along the stroke axis (H) in front of the piston (120) and a rear chamber (112) along the stroke axis (H) behind the piston (120); a piston rod (130) attached to the piston (120), wherein the piston rod (130) extends out of the pressure tube (110) through the rear chamber (112) along the stroke axis (H); and a bypass (140) arranged outside the pressure tube (110), wherein the bypass (140) conductively connects the front chamber (111) for the damping fluid to the rear chamber (112).The bypass (140) is at least partially bounded by a bypass wall (141), wherein the bypass wall (141) is elastically deformable to accommodate a volume of damping fluid displaced into the bypass (140) by the piston rod (130) when the piston rod (130) is inserted into the pressure tube (110).