Clamping Device Sealing Ring and Damping Cover

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Solution Overview

Problem

Existing clamping devices for machine tools face issues with chip accumulation leading to imbalance and coolant leakage, particularly at high rotational speeds and with internal coolant supply systems.

Innovation Solution

A clamping device with a sealing ring in an annular groove that seals the gap around the tool shank, combined with a damping cover that can swing freely to absorb vibrations, and a liquid supply system to prevent coolant escape and adjust damping properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an annular damping space is provided around the receptacle to soften clamping, then tool breakage due to cardan effects is prevented, but chip accumulation in the damping cavities causes imbalance

Engineering Contradiction:
Improveprevention of tool breakageVSAvoidchip accumulation causing imbalance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The harmful function of the annular space (chip accumulation) is separated from the useful function (damping). The cover extracts the damping function while the sealing ring extracts the chip exclusion function, allowing the annular space to serve its damping purpose without the harmful side effect of chip accumulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sealing ring acts as an intermediary element between the annular damping space and the external environment. It allows the damping space to exist and function while preventing chips from entering and accumulating, thus mediating between the conflicting requirements of damping and chip exclusion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If gaps form between the holder and clamped tool for coolant access, then internal coolant supply is enabled, but coolant leakage occurs at the tool-side end face

Engineering Contradiction:
Improveinternal coolant supply capabilityVSAvoidcoolant leakage
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The sealing ring serves as an intermediary that allows coolant to pass through the tool shank while preventing it from leaking at the end face. It mediates between the need for coolant access and the need to prevent leakage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing ring is a flexible elastic element that can deform to accommodate the tool shank while maintaining the sealing function. This flexibility allows it to adapt to the tool dimensions while preventing coolant leakage.

Inventive Principle:
Principle #30Flexible shells and thin films

3Object-generated harmful factors

If a sealing ring is added to prevent coolant leakage, then coolant escape is stopped, but device complexity increases

Engineering Contradiction:
Improvecoolant leakage preventionVSAvoidnumber of sealing components
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The sealing ring is designed to perform multiple functions simultaneously: sealing against coolant leakage, allowing tool insertion/removal, and accommodating thermal expansion. This multi-functionality reduces the need for additional separate components.

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

Solution Approach 2:

The sealing ring's inner diameter is designed to be larger than the shank diameter, allowing for parameter variation that accommodates different tool sizes while maintaining the sealing function. This flexibility reduces the need for multiple sealing components for different tool types.

Inventive Principle:
Principle #35Parameter changes

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 effectively prevents chip accumulation-induced imbalance and coolant leakage, while providing adjustable damping to maintain tool stability and efficiency during high-speed operations.

Implementation Method 1

which can be actively pressed together by applying liquid pressure so that it rests against the circumference of a tool shank

Methodology Applied
Scientific EffectLiquid pressure: Pressure Increase

Implementation Method 2

When the liquid pressure is reduced again, the sealing ring pushes back into its original position due to its elastic restoring force

Methodology Applied
Scientific EffectElastic restoring force: Elasticity

Implementation Method 3

the annular groove formed in the inner wall of the cover on the receptacle side is supplied with a cooling liquid via the liquid feed channel

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP1844886B1Clamping device
Publication Date: 2009.08.19 SCHUNK GMBH & CO KG
  • EP1844886B1 patent drawingFigure 1
  • EP1844886B1 patent drawingFigure 2~3

AI summary

The present invention relates to a clamping device for clamping tools with a receptacle (2) surrounded by an annular space (3). The annular space (3) is open towards the workpiece-side end face (1a) of the chuck body (1) and towards the receptacle (2) and is closed by a cover (5). An annular groove (13) is formed in the receptacle-side inner wall of the cover (5), in which a sealing ring (12) is arranged. A liquid can be supplied to the annular groove (13) to press the sealing ring (12) inserted into the annular groove (13) inwards and thus actively seal a gap formed between the cover (5) and a tool (W) inserted into the receptacle (29).