Linear Motor Support Tube Grounding and Bearing Segmentation

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Solution Overview

Problem

Existing linear motors face limitations due to the risk of the rotor coming into contact with drive windings, which can lead to dangerous situations, and current solutions like grounding the rotor are cumbersome and expensive, while continuous slide bearings require high precision and can jam or wear out, necessitating replacement of the entire motor.

Innovation Solution

A linear motor design featuring a support tube with a length matching or exceeding the stator, made of chromium steel, which serves as a grounded bearing to prevent contact with drive windings and allows for easy replacement, combined with a sliding bearing system that includes multiple bearing rings and lubricant storage gaps for enhanced durability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grounding the rotor by means of a trailing cable is implemented, then the safety problem (contact of the rotor with the drive windings) can be avoided, but the solution is cumbersome and expensive to implement

Engineering Contradiction:
ImprovesafetyVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A conductive support tube is introduced as an intermediary component between the rotor and ground. The support tube is grounded and positioned to intercept the rotor before it can contact the drive windings, thereby providing safety without requiring complex rotor grounding systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The bearing system is segmented into a support tube component and a plain bearing component. The support tube handles the grounding and safety function separately from the plain bearing's mechanical support function, allowing independent optimization and replacement of each component

Inventive Principle:
Principle #1Segmentation

2Reliability

If a continuous slide bearing made of plastic is used, then the plain bearing extends over the entire length of the stator and is more durable, but very high demands are placed on the precision in the production of such a plain bearing

Engineering Contradiction:
ImprovedurabilityVSAvoidprecision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The continuous plain bearing is segmented into multiple individual bearing rings that can be separately manufactured and assembled. This allows each ring to be produced with standard precision tolerances rather than requiring the entire bearing to be manufactured as a single high-precision component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support tube serves multiple functions: it provides structural support, acts as a ground reference, and serves as a precision guide for the bearing rings. By concentrating precision requirements in the support tube rather than the bearing itself, manufacturing becomes more feasible

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

3Reliability

If the plain bearing is rubbed through, then the rotor will come into contact with the drive winding and then be under tension, but the entire linear motor must be replaced

Engineering Contradiction:
ImproveprotectionVSAvoidreplaceability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The bearing system is divided into replaceable bearing rings and a reusable support tube. When the plain bearing wears through, only the bearing rings need to be replaced rather than the entire motor, significantly reducing repair costs and downtime

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support tube is designed with sufficient length and grounding to provide a safety buffer that prevents rotor contact with drive windings even when the plain bearing fails. This prior cushioning measure protects against catastrophic failure and enables simple bearing replacement without motor replacement

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 prevents rotor contact with drive windings, ensuring safety and efficiency while allowing for extended maintenance intervals and reduced costs by enabling the replacement of only the worn-out bearing tube, rather than the entire motor, and maintains high precision and efficiency.

Implementation Method 1

the support tube, which preferably has a high level of strength and electrical conductivity and is grounded

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the support tube, which preferably has a high level of strength and electrical conductivity and is grounded

Methodology Applied
Scientific EffectGrounding: Earthing

Implementation Method 3

a plain bearing that rests on the inside of the support tube, in which the rotor is mounted so that it can move axially

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2390990B1Linear motor
Publication Date: 2015.12.02 NTI
  • EP2390990B1 patent drawingFigure 1
  • EP2390990B1 patent drawingFigure 2
  • EP2390990B1 patent drawingFigure 3

AI summary

The motor (1) has a stator (2), a rotor (3) and a support pipe (4) that are arranged in an inner side of the stator. The support pipe has a carrier pipe (40) whose length is equal to that of the stator. A slide bearing (41) lies at an inner side of the carrier pipe, where the rotor is supported in the slide bearing in an axially movable manner. The support pipe is arranged in the stator in an exchangeable manner. The stator has magnetically-conducting elements i.e. iron sheet packets and magnetically non-conducting partitions i.e. plastic disks (20).