Tool Holder Mixing Chamber for Minimum Volume Lubrication

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Solution Overview

Problem

In cutting machine tools, the use of oil mist for minimum quantity lubrication can lead to uneven distribution of lubricant, resulting in reduced effectiveness due to 'bleeding' of the liquid-gas mixture, where part of the oil-air mixture gets onto channel and bore walls and is no longer available uniformly at the tool cutting edges.

Innovation Solution

A mixing chamber is integrated into the tool holder, where a container filled with lubricating and/or cooling liquid is sealed and opened by the pressure of the liquid/gas mixture, ensuring a controlled addition of the liquid to the aerosol stream, maintaining a consistent lubricant saturation at the machining point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If compressed air is added to the liquid to create oil mist for minimum quantity lubrication, then the liquid content can be reduced to a minimum amount per unit of time, but part of the oil-air mixture gets onto the channel and bore walls and is eliminated in dead water zones, resulting in uneven distribution and reduced effectiveness

Engineering Contradiction:
Improveliquid contentVSAvoidlubrication effectiveness
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The delivery system is segmented into multiple independent channels (first channel for liquid-gas mixture, second channel for additional liquid) that can operate independently. This allows the liquid to be delivered through separate pathways, ensuring that the liquid component can reach the cutting point reliably even when the aerosol distribution is uneven.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A second liquid supply line acts as an intermediary mechanism to supplement the liquid content. When the aerosol's liquid portion is insufficient due to bleeding losses, this intermediary liquid supply directly compensates for the deficiency, maintaining reliable lubrication effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the liquid-gas mixture is supplied through channels and bores, then the system achieves minimum quantity lubrication, but the liquid-gas mixture bleeds onto channel and bore walls and is no longer available uniformly at the tool cutting edges

Engineering Contradiction:
Improveminimum quantity lubricationVSAvoiduniform distribution
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

Different parts of the delivery system have different functions: the first channel delivers the liquid-gas mixture while the second channel specifically targets liquid supplementation. This local differentiation ensures that areas with poor aerosol distribution (channel walls, dead zones) receive additional liquid directly, compensating for the non-uniform distribution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the parameter of liquid delivery by introducing a separate liquid supply line that can independently control liquid flow. This allows the liquid content parameter to be adjusted and maintained at optimal levels at the cutting point, regardless of variations in aerosol distribution.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a container filled with lubricating liquid is sealed and opened by pressure, then controlled addition of liquid to the aerosol stream is achieved, but the system complexity increases with additional valves and pressure control mechanisms

Engineering Contradiction:
Improvecontrolled liquid additionVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The container is designed to open automatically when the liquid-gas mixture pressure reaches a certain level. The system serves itself by using the incoming pressure to trigger the liquid release, eliminating the need for external control mechanisms, sensors, or complex valve actuation systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pressure of the incoming liquid-gas mixture itself is utilized to open the container and control liquid flow. This pneumatic/hydraulic self-actuation mechanism replaces complex mechanical or electronic control systems, achieving controlled liquid addition through fluid pressure alone.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 solution ensures consistent lubrication by counteracting 'bleeding' and maintaining a minimum quantity lubrication system, where the liquid content is maintained within the desired range, ensuring effective lubrication and cooling at the cutting point.

Implementation Method 1

If the liquid is then atomized in a nozzle and compressed air is fed into a mixing zone, an oil mist with e.g. micrometer-sized oil droplets can form.

Methodology Applied
Scientific EffectAtomization:

Implementation Method 2

A container filled with lubricating and/or cooling liquid is arranged in the housing, the liquid supply lines of which, which can be opened by the pressure of the liquid/gas mixture, end in or in front of the mixing chamber or mixing zone.

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP2323806B1Exchange assembly having minimum volume lubrication, device, and method
Publication Date: 2012.02.08 ZIMMER GUNTHER
  • EP2323806B1 patent drawingFigure 1
  • EP2323806B1 patent drawingFigure 2
  • EP2323806B1 patent drawingFigure 3~4

AI summary

The invention relates to an exchange assembly having a tool holder which holds tools, is supported in a housing and driven by a drive, wherein parts of the drive, parts of the tool holder, and the tool itself comprise channels or holes for transporting a pressurized cooling and/or lubricating liquid-gas mixture. A mixing chamber is disposed in or upstream of the tool holder, into which the liquid-gas mixture feed line opens. A container filled with lubricant and/or coolant is present in the housing, the liquid inlet lines thereof - opened by the pressure of the liquid-gas mixture - ending in or upstream of the mixing chamber. The present invention develops an exchange assembly and a method for minimum volume lubrication of the tool-side cutting point, wherein the liquid-gas mixture does not fall below a certain lubricant saturation at the cutting point.