Brush Seal Tool Holder for High-Speed Spindle Protection

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Solution Overview

Problem

Conventional tool holders in high-speed machining environments face challenges in protecting the spindle bearing from external contaminants due to high loads and the limitations of conventional radial shaft sealing rings, which require additional measures like compressed air supplies to prevent media ingress, leading to increased costs and wear.

Innovation Solution

A tool holder design featuring a brush seal with bristles made of a flexible, flat plastic insert strip and a labyrinth seal, which eliminates the need for compressed air and provides a reliable, abrasion-resistant seal capable of operating at high speeds without wear, using a brush seal formed from permanently abrasion-resistant polypropylene bristles and a labyrinth seal to manage high-pressure cooling lubricant jets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional radial shaft sealing rings (Simmerrings) are used at high speeds, then sealing function is provided, but rapid wear occurs and sealing reliability deteriorates

Engineering Contradiction:
Improvesealing reliabilityVSAvoidservice life of seal
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent changes the material parameter from conventional radial shaft sealing ring material to brush seal material, which can operate at peripheral speeds up to 500 m/s without rapid wear. This material parameter change enables the seal to withstand high-speed machining conditions while maintaining sealing reliability and extending service life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The brush seal is designed as a replaceable insert strip that can be easily exchanged when worn. This disposable approach allows the sealing function to be maintained at low cost by simply replacing the inexpensive brush seal insert rather than the entire sealing system, resolving the contradiction between sealing reliability and service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If compressed air supply is used to form air curtain barrier, then protection against media penetration is improved, but operating costs and device complexity increase

Engineering Contradiction:
Improveprotection against media penetrationVSAvoidcomplexity of sealing system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The brush seal is a passive sealing element that protects the bearing point without requiring external compressed air supply. The brush bristles physically block contaminants and cooling lubricant from reaching the bearing, eliminating the need for active air curtain systems and their associated complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts and eliminates the compressed air supply system from the sealing solution. By using a brush seal that provides inherent sealing capability, the complex air distribution unit and external compressed air supply are removed, reducing device complexity while maintaining protection against media penetration.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If compressed air supply is used to form air curtain, then sealing performance is improved, but energy consumption and operating costs increase

Engineering Contradiction:
Improvesealing performanceVSAvoidenergy consumption for compressed air
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The brush seal operates passively without consuming energy from compressed air supplies. The bristles naturally contact the spindle and create a sealing barrier through their physical structure, eliminating energy consumption associated with air compression and distribution systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the pneumatic system (compressed air supply) with a mechanical brush seal system. This substitution eliminates the energy consumption required to generate and distribute compressed air while maintaining effective sealing performance through direct mechanical contact of the brush bristles with the spindle.

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

4Productivity

If high spindle speeds are used for high-performance machining, then productivity is improved, but sealing requirements become more stringent and bearing point is exposed to higher risks

Engineering Contradiction:
Improvemachining speedVSAvoidbearing protection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the sealing parameter to accommodate high spindle speeds by using brush seals designed for peripheral speeds up to 500 m/s. This parameter change enables the sealing system to maintain reliability under the high-speed conditions required for high-performance machining and increased productivity.

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 ensures secure protection of the spindle bearing against contaminants and reduces energy loss and operating costs by eliminating the need for compressed air, maintaining a reliable seal over long periods and withstanding high-speed operations and high-pressure cooling lubricant jets.

Implementation Method 1

The very low friction only leads to low heat generation and thus to low energy loss

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the labyrinth seal breaks up the incident jet of cooling lubricant to such an extent that only pressureless cooling lubricant is present at the brush seal

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP3187302B1Tool holder
Publication Date: 2020.10.14 SAUTER FEINMECHANIK GMBH
  • EP3187302B1 patent drawingFigure 1
  • EP3187302B1 patent drawingFigure 2~4
  • EP3187302B1 patent drawingFigure 5

AI summary

1. Tool holder. 2. A tool holder, particularly for use in tool turrets, comprising a housing (1) and a tool spindle (5) rotatably mounted and driven therein by means of at least one bearing point (3), the tool spindle having a receiving chamber (7) for receiving an interchangeable machining tool, wherein a sealing device (45) is arranged between the housing (1) and the tool spindle (5), is characterized in that at least one seal of the sealing device is formed from a brush seal (45). 3. Fig. 1.