Segmented Sliding Bearing Bushing for Precise Rotor Unit Molding

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Solution Overview

Problem

Existing methods for producing rotor and bearing units, such as those used in canned motors and pumps, face challenges in achieving precise and cost-effective large-scale production due to tolerance issues and the need for post-processing in the transfer molding and injection molding processes, which result in increased manufacturing costs and reduced service life.

Innovation Solution

The method involves forming the plain bearing bush in at least two parts with a connection fit that allows relative movement, enabling precise positioning and eliminating the need for machining, by using a transfer molding or injection molding process where the bushing sections are placed in a mold with a connecting fit, allowing for independent production and adaptation of the bushing sections to maintain desired tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transfer molding or injection molding is used to produce the rotor unit, then large quantities can be produced, but tolerance ranges are large and manufacturing precision deteriorates

Engineering Contradiction:
Improveproduction quantityVSAvoidtolerance range
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The plain bearing bush is divided into two separate bushing sections (first and second sections) that can be produced independently using transfer molding or injection molding. Each section can be manufactured with controlled tolerances separately, and then assembled together to form the complete bearing bush, thereby achieving both high productivity and acceptable manufacturing precision.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a one-piece plain bearing bush is produced by transfer molding or injection molding, then production is simplified, but post-processing machining is required to maintain length tolerances

Engineering Contradiction:
Improveproduction process complexityVSAvoidlength tolerance
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The bearing bush is segmented into two sections that are assembled together. The first bushing section has a first end and the second bushing section has a second end, allowing the overall length to be controlled by the assembly configuration rather than requiring precision machining of a one-piece component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A connection fit is introduced as an intermediary element between the two bushing sections. This connection fit enables precise positioning and length control through the assembly of the two sections, eliminating the need for post-processing machining while maintaining the desired length tolerances.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach reduces manufacturing costs and extends the service life of the rotor and bearing units by allowing precise dimensional accuracy and adaptation of the bearing surfaces without the need for post-processing, while maintaining the desired tolerances and reducing the complexity of the manufacturing process.

Implementation Method 1

the rotor being formed by attaching a polymeric material to the journal bearing bushing in the mold by means of a transfer molding process or injection molding process

Methodology Applied
Scientific EffectTransfer molding:

Implementation Method 2

the rotor being formed by attaching a polymeric material to the journal bearing bushing in the mold by means of a transfer molding process or injection molding process

Methodology Applied
Scientific EffectInjection molding:

Data Source

PatentEP3604842B1Method for producing a rotor unit
Publication Date: 2021.01.20 SCHUNK SINTERMETALLTECHN
  • EP3604842B1 patent drawingFigure 1
  • EP3604842B1 patent drawingFigure 2

AI summary

The invention relates to a method for manufacturing a rotor unit or a bearing unit, wherein the rotor unit or bearing unit is formed with a rotor or a bearing housing and a sliding bearing bushing (20) for rotatably arranging the rotor on an axis, wherein the sliding bearing bushing is inserted into a mold (21), wherein the rotor or the bearing housing is formed in the mold by applying a polymeric material to the sliding bearing bushing by means of an injection molding process or an injection molding process, wherein the sliding bearing bushing is formed from a first bushing section (25) and a second bushing section (26) connected to the first bushing section, wherein the bushing sections are inserted into the mold, and wherein the polymeric material is applied to the bushing sections.