Elastic Fluid Actuator Structure Without Moving Seals

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Solution Overview

Problem

Existing fluid-technical energy storage systems, such as those used in brake systems for commercial vehicles, face issues with energy loss due to thermal effects and wear of moving seals, which are dynamically loaded and require frequent replacement.

Innovation Solution

An actuator device with an elongate body having a laterally extending surface that is elastic, allowing it to lengthen or compress under fluid pressure, eliminating the need for moving seals by using static seals and storing energy through deformation work, which is released as kinetic energy when pressure is reduced.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If moving seals are used in brake actuators to maintain brake pressure, then sealing effectiveness is improved, but seal wear increases and service life decreases

Engineering Contradiction:
Improvesealing effectivenessVSAvoidseal service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The invention extracts and eliminates the moving seal component from the brake actuator system. Instead of using dynamic seals between the brake piston and cylinder that are subject to wear, the patent employs static seals at the ends of the piston rod, combined with a spring mechanism that maintains sealing contact without relative motion during braking operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention inverts the traditional sealing approach by placing seals at the stationary ends of the piston rod rather than using moving seals along the piston-cylinder interface. The sealing function is achieved through static contact points that do not undergo relative motion, thereby eliminating wear while maintaining pressure containment.

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

2Reliability

If dynamic seals are used to prevent brake pressure escape, then sealing performance is improved, but maintenance effort and replacement cost increase

Engineering Contradiction:
Improvepressure containmentVSAvoidseal replacement effort
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The invention removes the maintenance-intensive moving seal component from the system. By replacing dynamic seals with static seals positioned at the piston rod ends, the design eliminates the need for frequent seal replacement while maintaining effective pressure containment throughout the brake actuator's operational life.

Inventive Principle:
Principle #2Taking out (Extraction)

3Use of energy by moving object

If thermal effects are utilized in gas-powered accumulators for energy storage, then energy density is improved, but energy loss increases

Engineering Contradiction:
Improveenergy storage densityVSAvoidthermal energy loss
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention replaces the gas-powered thermal energy storage system with a mechanical spring-based energy storage mechanism. The spring accumulates elastic potential energy through compression or extension, eliminating thermal effects and associated energy losses while providing comparable or superior energy storage density for brake actuation applications.

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

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 design reduces wear on seals, increases service life, and efficiently converts stored energy into kinetic energy for actuator functions without the need for dynamic seals, enhancing the reliability and longevity of brake systems.

Implementation Method 1

The lateral surface has elasticity, at least in sections, preferably in the direction of its longitudinal axis. The elasticity of the lateral surface corresponds to the spring stiffness of a spring used, for example, in a conventional brake actuator. The actuator device can thus be elastically lengthened or compressed by the pressure due to the predetermined elasticity.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The energy that can be emitted is used to exercise an actuator function. The energy stored via the elongation or compression in the form of deformation work can be made available as kinetic energy for exercising an actuator function.

Methodology Applied
Scientific EffectDeformation work: Deformation

Data Source

PatentEP3754220B1Actuator device and actuator system
Publication Date: 2022.03.30 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP3754220B1 patent drawingFigure 1~2
  • EP3754220B1 patent drawingFigure 3~4
  • EP3754220B1 patent drawingFigure 5~6

AI summary

The present invention relates to an actuator device comprising at least one elongated body with a longitudinal axis (100), comprising: a lateral surface (13) extending about its longitudinal axis (100) and forming a cavity (11), wherein the lateral surface (13) has at least sectionally a predetermined elasticity in the longitudinal direction, a base plate (20) configured to limit the cavity (11) at an end face in the axial direction of the longitudinal axis (100), and an end-face boundary (12) configured to seal the cavity (11) at an end face opposite the base plate (20) in the axial direction of the longitudinal axis (100), wherein the cavity (11) can be pressurized by introducing or removing a fluid, so that the actuator device can be elastically elongated or compressed by the pressure due to the predetermined elasticity.and wherein the actuator device is configured such that the energy stored in the form of deformation work through elongation or compression is available as kinetic energy for performing an actuator function.