Spindle Fluid Supply Labyrinth Seal for Easier Machine Tool Mounting

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Solution Overview

Problem

Machine tools face challenges in preventing fluid leakage when a fluid supplying unit is mounted on a rotatable spindle, as adjusting the clearance between the stationary and rotating parts is difficult, leading to inefficient fluid supply and increased parts replacement time.

Innovation Solution

A machine tool design incorporating a labyrinth clearance between the outer circumferential surface of the fluid supplying unit's insert and the inner circumferential surface of the rotating unit, allowing rotation while restricting fluid leakage, eliminates the need for precise clearance adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a narrower clearance is provided between the stationary fluid supplying unit and the rotatable spindle, then fluid leakage is reduced, but the spindle interferes with the fluid supplying unit due to thermal expansion

Engineering Contradiction:
Improvefluid leakageVSAvoidspindle rotation
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

The clearance space is segmented into multiple narrow gaps (labyrinth structure) rather than one large gap. The insert has a stepped structure with multiple diameters creating several clearance zones, which collectively restrict fluid leakage while allowing thermal expansion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert is nested within the rotating unit, creating a concentric labyrinth structure. The insert's outer circumferential surface is received within the inner circumferential surface of the rotating unit, forming nested clearance zones that restrict fluid flow paths

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If a wider clearance is provided between the stationary fluid supplying unit and the rotatable spindle, then the spindle can rotate freely, but fluid leakage increases resulting in less fluid supplied to the collet

Engineering Contradiction:
Improvespindle rotationVSAvoidfluid leakage
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The clearance space is segmented into multiple narrow gaps (labyrinth structure) rather than one large gap. The insert has a stepped structure with multiple diameters creating several clearance zones, which collectively restrict fluid leakage while allowing thermal expansion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution moves from controlling clearance in one radial dimension to creating a multi-dimensional labyrinth path. The fluid must traverse multiple gaps at different radial positions and axial locations, increasing the effective sealing path length without restricting radial movement

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of substance

If precise clearance adjustment is required for optimal fluid supply, then fluid leakage is reduced, but parts replacement time increases and operator skill is required

Engineering Contradiction:
Improvefluid leakageVSAvoidparts replacement time
Core Design Contradiction:
Loss of substanceVSLoss of time

Solution Approach 1:

The labyrinth clearance structure self-regulates fluid leakage without requiring operator adjustment. The geometric configuration of the insert and rotating unit automatically creates the optimal sealing effect through their relative rotation, eliminating the need for skilled adjustment

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the parameter from adjustable clearance width to fixed geometric clearance configuration. The insert's predetermined stepped dimensions create consistent clearance zones that maintain optimal fluid sealing across different operating conditions without adjustment

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

This design facilitates easier mounting of the fluid supplying unit, reduces fluid leakage, and decreases parts replacement time by automatically forming a seal that maintains consistent fluid supply, regardless of operator experience.

Implementation Method 1

A labyrinth clearance is formed between the outer circumferential surface of the insert and the inner circumferential surface of the rotating unit when the fluid supplying unit is mounted on the supporting unit. The labyrinth clearance allows rotation of the rotating unit and restricts leak of fluid from the spindle when the rotating unit is rotated.

Methodology Applied
Scientific EffectLabyrinth seal:

Data Source

PatentEP3375565B1Machine tool
Publication Date: 2024.09.18 STAR MICRONICS CO LTD
  • EP3375565B1 patent drawingFigure 1
  • EP3375565B1 patent drawingFigure 2
  • EP3375565B1 patent drawingFigure 3

AI summary

The invention provides a machine tool capable of facilitating a process of mounting a fluid supplying unit to a spindle supporting unit. The machine tool comprisies a rotating unit (U1) including a spindle (52) provided with a workpiece chucking unit, a supporting unit (U2) which rotatably supports the spindle around a spindle axis, and a fluid supplying unit (U3) removably mounted on the supporting unit to supply fluid to the chucking unit via the spindle. The fluid supplying unit has an insert (P1) to be received in the rotating unit in the direction of the spindle axis. A labyrinth clearance (C1) is formed between the outer circumferential surface of the insert and the inner circumferential surface of the rotating unit when the fluid supplying unit is mounted on the supporting unit. The labyrinth clearance allows rotation of the rotating unit and restricts leak of fluid from the spindle when the rotating unit is rotated.