Electric Machine Laser Welding Metal Ring Protection

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Solution Overview

Problem

The combination of a plastic connector component and a metal pole housing and cover in existing electrical machines does not provide reliable heat dissipation and electromagnetic compatibility (EMC) shielding, and the laser welding process poses a risk of damaging sensitive components with high-energy input.

Innovation Solution

A metal ring is strategically placed inside the joint gap between the pole housing and the metal cover to absorb scattered laser beams during welding, ensuring they do not penetrate and damage internal components, while an axial spring element secures the metal ring and connector housing, enhancing EMC shielding and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If laser welding is used to join the metal cover to the pole housing, then welding efficiency and strength are improved, but scattered laser beams can penetrate the housing and damage sensitive internal components

Engineering Contradiction:
Improvewelding efficiencyVSAvoidlaser beam penetration damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

A metal ring is introduced as an intermediary component positioned between the laser welding zone and the internal components. This metal ring absorbs scattered laser beams, preventing them from penetrating into the housing and damaging sensitive components while allowing the welding process to proceed efficiently.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The metal ring is strategically positioned to convert the harmful scattered laser radiation into beneficial heat absorption. By placing the metal ring in the path of scattered laser beams, the harmful radiation is absorbed and dissipated as heat in the metal ring, protecting internal components while maintaining welding efficiency.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of manufacture

If a plastic connector component is used, then manufacturing flexibility and cost are improved, but heat dissipation and EMC shielding are insufficient

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidheat dissipation and EMC shielding
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The housing structure employs a composite design combining plastic and metal materials. The plastic connector component provides manufacturing flexibility and cost benefits, while the integrated metal ring and metal cover provide superior heat dissipation and electromagnetic compatibility shielding, creating a hybrid structure that leverages the advantages of both materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the housing structure use different materials optimized for their specific functions. The plastic connector component is used where manufacturing flexibility is needed, while metal components (metal ring and metal cover) are strategically positioned where heat dissipation and EMC shielding are critical, achieving local optimization of material properties.

Inventive Principle:
Principle #3Local quality

3Strength

If metal components are welded together, then structural strength is improved, but the risk of laser beams damaging internal components increases

Engineering Contradiction:
Improvestructural strengthVSAvoidlaser beam penetration
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The metal ring serves as a protective intermediary component positioned between the laser welding zone and internal components. It absorbs scattered laser beams during the welding process, preventing penetration damage to sensitive components while allowing the metal cover to be securely welded to the pole housing for structural strength.

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 configuration effectively protects sensitive components from laser damage, ensures reliable welding, and provides robust electromagnetic shielding, creating a vibration-resistant and efficient heat dissipation system.

Implementation Method 1

laser beams scattered during laser welding are effectively absorbed by the arrangement of a metal ring as radiation protection on the inside of the joint gap between the pole housing and the metal cover

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

laser beams scattered during laser welding are effectively absorbed by the arrangement of a metal ring as radiation protection

Methodology Applied
Scientific EffectLaser: Laser

Data Source

PatentEP3625877B1Electric machine and method of production
Publication Date: 2022.04.13 ROBERT BOSCH GMBH
  • EP3625877B1 patent drawingFigure 1
  • EP3625877B1 patent drawingFigure 2
  • EP3625877B1 patent drawingFigure 3

AI summary

The invention relates to an electric machine (10), in particular an electronically commutated (EC) motor, and a method for producing same, comprising a pole housing (15) in which a stator (16) and a rotor (18) are accommodated, and a plug housing (33) made of plastic and having an integrated connection plug (37) is arranged axially on an open side (31) of the pole housing (15), wherein the plug housing (33) is surrounded by a metal cover (81) over its entire perimeter, which is sealingly welded to the open side (31) of the pole housing (15) by means of a peripheral laser weld seam (90), wherein an uninterrupted peripheral metal ring (88) is arranged as a beam protector radially inside the laser weld seam (90), which metal ring is positioned in the beam path of a laser (91) which can penetrate into the internal space of the electric machine (10) through a joining gap between the pole housing (15) and the metal cover (81) during laser welding.