Rotary Table Seal Structure for Sludge-Resistant EDM Machining

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Solution Overview

Problem

Existing rotary table apparatuses for electric discharge machines suffer from early seal mechanism degradation due to sludge accumulation, leading to reduced sealing performance.

Innovation Solution

Incorporation of a sludge entrance preventing unit with a clean fluid supply system that includes a discharge port for the seal mechanism and an auxiliary seal mechanism, allowing for the separation of these components from the rotary table body, enabling long-term sealing performance by preventing sludge contact with the sealers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal mechanism is provided in a clearance between the rotary table casing and the face plate to prevent working fluid from entering the rotary table, then sealing performance is improved, but sludge (fine metal powder) generated during machining flows into the seal mechanism, resulting in significant degradation of sealing performance

Engineering Contradiction:
Improvesealing performanceVSAvoidsludge accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a sludge prevention mechanism as an intermediary component between the working fluid environment and the seal mechanism. This mechanism includes a sludge prevention member that actively removes or prevents sludge from reaching the seal, thereby protecting the seal from degradation while maintaining the sealing function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary protection by positioning the sludge prevention member upstream of the seal mechanism in the fluid flow path. This preliminary action prevents sludge from reaching the seal in the first place, rather than attempting to clean or repair the seal after sludge accumulation occurs.

Inventive Principle:
Principle #10Preliminary action

2Ease of repair

If the seal mechanism is made separable from the rotary table body to facilitate maintenance, then ease of repair is improved, but device complexity increases due to additional sealing interfaces and assembly requirements

Engineering Contradiction:
Improveseal mechanism maintenanceVSAvoidseal mechanism structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The patent divides the seal mechanism into separable components, specifically making the sludge prevention member and seal mechanism detachable from the rotary table body. This segmentation allows individual components to be removed and replaced independently, simplifying maintenance while the modular design manages the complexity through standardized interfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic maintenance approach where the seal mechanism transitions from a fixed to a movable state during maintenance operations. The separable design allows the seal mechanism to be easily detached and reattached, providing flexibility in maintenance scheduling and reducing downtime without requiring complex disassembly procedures.

Inventive Principle:
Principle #15Dynamics

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 maintains long-term sealing performance by preventing sludge from entering the seal mechanism, reducing abrasion and allowing for simplified cleaning and maintenance, thereby extending the lifespan of the sealers and improving operational efficiency.

Implementation Method 1

a clean fluid supply unit configured to supply clean working fluid to the seal mechanism

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

the seal mechanism may have a discharge port of clean fluid for use in machining

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP3009219B1Rotary table apparatus and electric discharge machine using the rotary table apparatus
Publication Date: 2021.06.02 FANUC LTD
  • EP3009219B1 patent drawingFigure 1
  • EP3009219B1 patent drawingFigure 2
  • EP3009219B1 patent drawingFigure 3

AI summary

A rotary table apparatus includes a rotary table body (1), a table rotor (5, 6) supported on the rotary table body and configured to be rotatable, a driving (2, 3) unit for driving the table rotor, a seal mechanism (9, 10, 11) including a sealer (9) disposed between the rotary table body and the table rotor, and a first supply unit (10) configured to supply clean fluid for use in machining to the seal mechanism.