Insulating Sleeve Assembly for Laminated Motor Shafts

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Solution Overview

Problem

The production of drive motors for suction devices and machine tools is complex due to the need for precise insulation of laminated cores from motor shafts, often requiring intricate encapsulation methods.

Innovation Solution

A simplified assembly method where an insulation sleeve is inserted into the shaft passage opening of the laminated core, serving as both a plug-in body and a receptacle for the motor shaft, providing complete electrical insulation and allowing for additional insulation measures such as plastic casting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If overmolding is used to insulate the laminated core from the motor shaft, then electrical insulation is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improveelectrical insulationVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

An insulating sleeve is introduced as an intermediary component between the laminated core and the motor shaft. This sleeve provides the necessary electrical insulation without requiring complex overmolding processes, thereby simplifying manufacturing while maintaining insulation reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulation function is segmented into a separate, removable insulating sleeve component rather than being integrated through complex overmolding. This allows the insulation element to be independently manufactured and assembled, reducing overall manufacturing complexity

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If an insulating sleeve is inserted into the shaft passage opening, then assembly is simplified, but additional insulation measures may be required

Engineering Contradiction:
Improveassembly processVSAvoidelectrical insulation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The insulating sleeve is pre-installed into the shaft passage opening of the laminated core before the motor shaft is assembled. This preliminary action simplifies the overall assembly process by having the insulation element ready in place, eliminating the need for complex post-assembly insulation measures

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3963691B1Drive motor with an insulating housing
Publication Date: 2024.07.24 FESTOOL GMBH
  • EP3963691B1 patent drawingFigure 1
  • EP3963691B1 patent drawingFigure 2~4
  • EP3963691B1 patent drawingFigure 5~9

AI summary

The invention relates to a drive motor for a vacuum device (400), or a machine tool in the form of a hand-held machine tool (200, 300) or a semi-stationary machine tool, the drive motor (20, 120) having a stator (80) with an excitation coil assembly (86) and a rotor (40, 140) with a motor shaft (30, 130) which is rotatably mounted, with the aid of a bearing assembly (24A), on the stator or in relation to the stator (80), about an axis of rotation (D), and which passes through a shaft passage (42, 142) of a lamination stack (41, 141) that is held on the motor shaft (30, 130) and is electrically insulated from the motor shaft (30, 130). According to the invention, an insulating sleeve (60) is provided between the motor shaft (30, 130) and the lamination stack (41, 141), said sleeve being plugged into the shaft passage (42, 142) and having a plug socket (64) with a plug-in opening (64A), through which the motor shaft (30, 130) can be plugged into the plug socket along a plug-in axis (S).