Motor-Gearbox Assembly with Riveted Anti-Unscrewing Lock

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Solution Overview

Problem

Existing methods for connecting components, such as a motor flange to a transmission ring gear, face challenges with securing under high loads, especially at extreme temperatures and in high vacuum conditions, as adhesives fail and welding can result in visual defects. Additionally, these methods can be complex and harmful.

Innovation Solution

The method involves axial securing through caulking using a tab on one component deformed into a recess on the other, with a caulking tool featuring a toothing that acts as a linear guide, allowing for a secure connection without adhesives or welding, and optionally using a profiling for anti-twist security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive bonding is used to secure the screw connection, then the connection is secured against unscrewing, but the adhesive fails in extreme temperature applications and high vacuum conditions

Engineering Contradiction:
Improvesecuring against unscrewingVSAvoidsuitability for operating conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the chemical bonding mechanism (adhesive) with a purely mechanical securing mechanism. The tab is deformed into the recess to create a positive mechanical lock that secures the screw connection against unscrewing, eliminating dependency on adhesive properties that fail under extreme conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The connection mechanism is segmented into distinct functional elements: the tab protruding from the first component, the recess in the second component, and the deformation zone where the tab is shaped into the recess. This segmentation allows each element to be optimized independently for its specific function.

Inventive Principle:
Principle #1Segmentation

2Reliability

If welding is used to secure the screw connection, then the connection is secured against unscrewing, but visual defects such as holes, shrinkage cavities, and discoloration occur

Engineering Contradiction:
Improvesecuring against unscrewingVSAvoidvisual appearance
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent replaces the thermal welding process with a cold-forming mechanical process. The tab is deformed into the recess through plastic deformation without melting or joining materials, thereby avoiding all visual defects associated with welding such as holes, shrinkage cavities, and discoloration.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The tab acts as a sacrificial element that is deformed and permanently shaped into the recess to create the securing function. This disposable-like approach eliminates the need for complex welding processes and their associated visual defects.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If a screwed connection is used for high load applications, then the connection strength is improved, but additional securing against unscrewing is required which increases complexity

Engineering Contradiction:
Improveconnection strength under loadVSAvoidsecuring mechanism complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the screw connection function with the securing against unscrewing function into a single integrated mechanism. The deformed tab simultaneously provides both the screw fastening and the anti-unscrewing security, eliminating the need for separate adhesive bonding or locking devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The tab-recess deformation mechanism serves multiple functions: it secures the screw connection against unscrewing, provides structural support, and creates a rigid joint. This multi-functional design reduces overall system complexity compared to using separate components for each function.

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

4Reliability

If adhesive bonding is used to secure the screw connection, then the connection is secured against unscrewing, but the application process becomes complex and potentially harmful

Engineering Contradiction:
Improvesecuring against unscrewingVSAvoidapplication process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the complex chemical application process of adhesive bonding with a simple mechanical deformation process. The tab is deformed into the recess using mechanical force, eliminating the need for adhesive application, curing time, and associated safety precautions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The tab-recess mechanism is self-securing through mechanical deformation. The process is self-contained and does not require external adhesives or additional securing steps, making the manufacturing process simpler and eliminating potential harmful chemical applications.

Inventive Principle:
Principle #25Self-service

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 method is easy, quick, cost-effective, and repeatable, suitable for components with teeth, ensuring both axial and circumferential security without the need for adhesives or welding, and is suitable for various operating conditions.

Implementation Method 1

an axial securing between the two components is produced by a tab (3) formed on the first component (1) being deformed by means of a caulking tool (4) into a recess (5) formed on the second component (2)

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP4108948B1Method for connecting two components, in particular a motor with a gearbox, and assembly with a connection between motor and transmission
Publication Date: 2024.05.22 MAXON MOTOR AG
  • EP4108948B1 patent drawingFigure 1
  • EP4108948B1 patent drawingFigure 2
  • EP4108948B1 patent drawingFigure 3

AI summary

The present invention relates to a method for connecting a motor to a gearbox, wherein a positive and/or force-fit connection between the motor and gearbox is first established by screwing a motor- or gearbox-side first component to the respective motor- or gearbox-side second component to be connected to it, or by creating a press fit between the two components, and wherein, in addition, an axial locking between the two components is subsequently created by means of riveting, by deforming a tab formed on the first component into a recess formed on the second component using a riveting tool.