Hydraulic Expansion Clamping with Membrane Pressure Compensation

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Solution Overview

Problem

Hydraulic expansion clamping devices face issues with maintaining constant clamping force during temperature fluctuations, leading to potential damage due to increased pressure from hydraulic fluid expansion during high-temperature workpiece processing.

Innovation Solution

Incorporating a hollow chamber separated by a compensating membrane within the pressure chamber arrangement, allowing the membrane to deform and absorb fluid expansion, thereby maintaining clamping force and preventing mechanical overstressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the hydraulic fluid is used to generate clamping force through pressure chamber arrangement, then the clamping force can be effectively applied to the component, but when temperature increases during workpiece processing, the hydraulic fluid expands and increases pressure on the thin wall, which may damage the clamping device

Engineering Contradiction:
Improveclamping forceVSAvoidpressure increase from fluid expansion
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The pressure chamber arrangement is segmented into multiple independent pressure chambers, each capable of expanding independently. This segmentation allows the system to better accommodate thermal expansion of the hydraulic fluid while maintaining effective clamping force distribution across the component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hollow chamber positioned behind the pressure chamber arrangement serves as a pre-designed cushioning space. When the hydraulic fluid expands due to temperature increase, it can expand into this hollow chamber, cushioning the pressure increase and preventing damage to the thin wall and clamping device components.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If a thin wall is formed between the receptacle and pressure chamber arrangement to enable elastic deformation for clamping, then the clamping device can effectively secure components, but the thin wall is vulnerable to damage from excessive pressure during temperature fluctuations

Engineering Contradiction:
Improveelastic deformation capabilityVSAvoidthin wall strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The hollow chamber acts as a pre-prepared cushioning space behind the pressure chamber arrangement. When thermal expansion causes pressure increase, the hydraulic fluid can expand into this hollow chamber, preventing excessive pressure from damaging the thin wall while preserving its elastic deformation capability for effective clamping.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The thin wall is designed as a flexible elastic deformation wall that can radially expand or contract based on pressure changes. This flexible design allows the wall to adapt to clamping requirements while the hollow chamber provides a safety buffer against excessive pressure that could compromise the wall's structural integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

3Power

If the pressure chamber arrangement is acted upon by hydraulic medium to deform the thin wall, then clamping force can be applied, but temperature increase causes hydraulic fluid expansion that may exceed the strength of the base body

Engineering Contradiction:
Improvehydraulic power transmissionVSAvoidbase body strength limitation
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The hollow chamber serves as a pre-designed safety buffer zone behind the pressure chamber arrangement. When thermal expansion of the hydraulic fluid generates excessive pressure that could compromise the base body, the fluid can expand into this hollow chamber, cushioning the pressure increase and preventing damage to the base body while maintaining hydraulic power transmission capability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The potential harmful effect of hydraulic fluid thermal expansion is converted into a beneficial feature. Instead of allowing uncontrolled pressure increase that could damage the base body, the expansion is directed into the hollow chamber, transforming what would be a harmful pressure surge into a controlled volume expansion that protects the structural integrity of the clamping device.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 ensures a consistent clamping force and prevents damage to the clamping device by allowing the hydraulic fluid to expand without increasing pressure on the thin wall, thus maintaining stability during temperature changes.

Implementation Method 1

when the temperature of the hydraulic fluid increases and it expands

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the compensating membrane can deform into the hollow chamber

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

a thin wall is formed between the receptacle and the pressure chamber arrangement which can be elastically deformed radially outwards or inwards by increasing the pressure in the pressure chamber

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4112211A1Hydraulic expansion device
Publication Date: 2023.01.04 SCHUNK GMBH & CO KG
  • EP4112211A1 patent drawingFigure 1
  • EP4112211A1 patent drawingFigure 2
  • EP4112211A1 patent drawingFigure 3

AI summary

The present invention relates to a hydraulic expansion clamping device (1), in particular for fixing a workpiece or a tool on a machine tool, with a base body (2) defining a longitudinal axis (X) on which a clamping area (3) is formed, wherein the clamping area (3) comprises a receptacle (4) with an external clamping surface (5) for a component and a pressure chamber arrangement (7) that can be pressurized with a hydraulic medium and arranged radially within the receptacle (4), wherein a thin wall (10) is formed between the receptacle (4) and the pressure chamber arrangement (7) such that it can be elastically deformed radially outwards by increasing the pressure in the pressure chamber arrangement (7) in order to fix a component pushed onto the receptacle (4) from the inside in a force-fit manner.