Linear Drive Guide Bearing With Hydrostatic Gap Control

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Solution Overview

Problem

Existing high-precision machine tools with linear drive means lack sufficient precision without increasing design complexity, which limits their ability to perform precise relative movements between machine components.

Innovation Solution

A high-precision machine tool design featuring a linear drive and guide bearing system with a combination of a linear motor and hydrostatic fluid bearings, where the linear motor consists of a magnet and coil setup with a ferrite core, and hydrostatic fluid bearings provide a repulsive force to maintain a precise bearing gap, allowing for adjustable movement and positioning of machine components in orthogonal planes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a linear motor with small air gap is used to improve precision, then manufacturing precision is improved, but device complexity increases due to tighter tolerances and more complex bearing arrangements

Engineering Contradiction:
Improveprecision of relative movementVSAvoidcomplexity of bearing arrangement
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple bearing functions into a single integrated bearing arrangement. The first and second bearing arrangements are merged into one unified structure that simultaneously provides guidance in multiple directions and supports the linear motor, thereby reducing overall device complexity while maintaining the small air gap needed for high precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bearing arrangement is designed to perform multiple functions simultaneously: it guides the moving component in orthogonal directions, supports the linear motor assembly, maintains precise spacing, and provides stability. This multi-functional design eliminates the need for separate components for each function, reducing complexity while achieving high manufacturing precision

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

2Manufacturing precision

If hydrostatic fluid bearings are used to maintain bearing gap, then manufacturing precision is improved, but use of energy increases due to continuous fluid supply requirement

Engineering Contradiction:
Improvebearing gap maintenanceVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The hydrostatic fluid supply is implemented with periodic activation rather than continuous flow. The fluid supply is activated only when bearing gap maintenance is required, allowing the system to consume energy intermittently rather than continuously, thereby reducing overall energy usage while maintaining precision

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If linear guide means with orthogonal planes are used, then manufacturing precision is improved, but device complexity increases due to additional structural components

Engineering Contradiction:
Improveguidance precisionVSAvoidstructural complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The linear guide means is integrated into the bearing arrangements rather than being separate components. The orthogonal guidance planes are formed as part of the bearing structure itself, merging the guidance function with the support function and reducing overall structural complexity while maintaining high guidance precision

Inventive Principle:
Principle #5Merging (Combining)

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 enhances precision and ease of manufacturing while maintaining a high level of efficiency and heat balance, enabling precise relative movement of machine components with adjustable bearing gaps, improving the overall accuracy and reliability of the machine tool.

Implementation Method 1

a linear motor having a magnet arranged on one of the machine components and a coil arranged on the other machine component and operatively connected to the magnet, wherein the magnet and the coil are configured to exert a mutual attractive force and an at least temporary relative movement to one another

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a hydrostatic fluid bearing arranged on one of the two machine components and operatively connected to the other machine component, wherein the hydrostatic fluid bearing exerts a repulsive force opposite to the attractive force

Methodology Applied
Scientific EffectHydrostatic pressure: Hydraulic Press

Data Source

PatentEP4017679B1High precision machine tool having linear drive- and guide bearing
Publication Date: 2025.01.15 KERN MICROTECHNIK GMBH
  • EP4017679B1 patent drawingFigure 1
  • EP4017679B1 patent drawingFigure 2
  • EP4017679B1 patent drawingFigure 3

AI summary

For the purposes of further improved precision of a high precision machine tool (100), at least one linear drive- and guide bearing (1) is provided having at least one linear motor (27), which has at least one magnet (15) arranged on one of the machine components (5) and at least one coil (25) arranged on the other machine component (10) and operatively connected to the at least one magnet (15), wherein the at least one magnet (15) and the at least one coil (25) are designed to exert an opposing attraction force and perform an at least temporarily relative movement toward each other. Also provided are at least one hydrostatic fluid bearing (30-1, 30-3) arranged on one of the two machine components (10) and operatively connected to the other machine component (5), wherein the hydrostatic fluid bearing (30-1, 30-3) exerts a repelling force directed opposite to the attraction force, and a first bearing gap (H1) formed between the two machine components (5, 10), having a height which is greater than 0 μm and less than or equal to 10 μm.