Door Drive Pressure Compensation via Piston and Hydraulic Fluid

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Solution Overview

Problem

Existing door and window drive systems face challenges with complex and potentially leaky sealing of pressure equalization devices, which can lead to inefficiencies and reliability issues due to aging, especially in thermal expansion scenarios.

Innovation Solution

A pressure compensation device is introduced, comprising a compensation housing filled with hydraulic fluid and a sleeve that extends into the differential housing, allowing for temperature-related volume changes to be compensated without moving parts or special sealing surfaces, and can be filled with vacuum to minimize gas presence, ensuring effective pressure equalization across varying temperatures and positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an elastic enveloping body is used to enclose gas volume for pressure equalization, then thermal expansion compensation is achieved, but sealing complexity increases and reliability decreases due to aging

Engineering Contradiction:
Improvethermal expansion compensationVSAvoidsealing reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent extracts the gas volume from an enclosed elastic structure and places it in an open chamber where it is bounded by the housing walls and a movable piston. This eliminates the elastic enveloping body and its associated sealing problems while maintaining the pressure equalization function through direct communication between the gas volume and hydraulic fluid.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The piston acts as an intermediary element between the gas volume and the hydraulic fluid. It transmits pressure changes from the thermal expanding/contracting gas to the hydraulic system without requiring seals, as the piston moves freely within the damping piston cavity while maintaining pressure equilibrium.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If complex sealing structures are used in pressure equalization devices, then pressure containment is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvepressure containmentVSAvoidmanufacturing simplicity
Core Design Contradiction:
Stress or pressureVSEase of manufacture

Solution Approach 1:

The pressure equalization function is segmented into two independent parts: a gas volume chamber and a hydraulic fluid chamber, separated by a piston. Each chamber can be manufactured and assembled separately, with the piston serving as a simple dividing element that requires no complex sealing between the two pressure zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces mechanical sealing systems (elastic enveloping bodies, sealed diaphragms) with a pressure-based equilibrium system where a movable piston allows pressure equalization without physical seals. The piston moves freely, transmitting pressure changes without requiring sealing surfaces.

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

3Temperature

If pressure equalization devices with moving parts are used, then pressure compensation is achieved, but device complexity increases

Engineering Contradiction:
Improvepressure compensationVSAvoidstructural complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The piston in the damping device serves multiple functions simultaneously: it acts as a separator between gas and hydraulic fluid, a pressure transmission element for thermal compensation, and a damping element for controlling fluid flow. This multi-functionality eliminates the need for separate pressure equalization mechanisms.

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

Solution Approach 2:

The patent merges the pressure equalization function with the existing damping piston structure. The damping piston's cavity becomes the gas volume chamber, and its movement provides both damping and pressure equalization functions in a single integrated component rather than requiring separate mechanisms.

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

The solution provides a simple, reliable, and position-independent pressure equalization, preventing the drive from 'falling through' due to air cushions, maintaining operational stability and efficiency by compensating for temperature-induced pressure changes without the need for complex sealing or moving parts, and allowing for flexible installation and temperature variations.

Implementation Method 1

Since gases are compressible or expandable, a temperature-related change in the volume of the hydraulic fluid is compensated

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The pressure compensation device is filled with hydraulic fluid to such an extent that the inner opening of the sleeve is always covered by hydraulic fluid

Methodology Applied
Scientific EffectHydraulic pressure transmission: Hydraulic Press

Data Source

PatentEP2388421B1Drive to operate the leaf of a door or window
Publication Date: 2016.08.03 GEZE GMBH
  • EP2388421B1 patent drawingFigure 1~2
  • EP2388421B1 patent drawingFigure 3~4
  • EP2388421B1 patent drawingFigure 5~6

AI summary

The unit (1) has a piston (3) arranged in a housing (2) and impacted with a spring (5) i.e. shutter spring. The piston co-acts with a driven shaft (4) for opening and/or closing a leaf. A pressure balance device (8) is arranged in the housing that is filled with hydraulic fluid (9). The pressure balance device has an input cabinet, whose inner space stands in contact with an inner space of the housing of the unit via a collet. The collet passes till to a volume middle point of the cabinet, and is closed via a stopper such that vacuum filling of the unit is enabled.