Harmonic Drive Anti-Twist Locking Mechanism

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Solution Overview

Problem

Existing wave gears in electromechanical camshaft adjusters lack effective mechanisms to securely prevent unintentional adjustments during transport or assembly without modifying the existing components, and existing solutions are either complex or not fully effective.

Innovation Solution

A concentric securing element, such as a plastic locking ring with a U-profile, is introduced that interacts positively with the adjusting element and non-positively with the drive element, providing anti-twist protection without geometric modifications, allowing for easy handling and secure locking in any angular position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking mechanism is added to prevent unintentional adjustment, then security against misalignment is improved, but device complexity increases

Engineering Contradiction:
Improvesecurity against misalignmentVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element is concentric with and nested between the drive element and output element, sharing the same rotational axis. This nested configuration provides effective anti-rotation protection without requiring additional space or complex external structures, thus improving security while minimizing device complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The locking element acts as an intermediary component that positively interacts with one connecting element and frictionally with another. This mediator approach enables secure locking without direct modification of the existing wave gear components, maintaining simplicity while achieving reliable anti-rotation protection

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If geometric modifications are made to existing components to enable locking, then security against misalignment is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesecurity against misalignmentVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking element serves as a separate intermediary component that can be added without modifying the existing wave gear components. This approach maintains the original geometry of the drive element, output element, and adjusting element, ensuring conventional manufacturing processes can be used while achieving secure anti-rotation protection

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The locking mechanism is segmented into a separate locking element rather than being integrated into the existing components. This segmentation allows the locking function to be added independently without requiring geometric modifications to the wave gear components, preserving manufacturing simplicity

Inventive Principle:
Principle #1Segmentation

3Reliability

If a secure locking mechanism is implemented, then protection against unintentional adjustment is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveprotection against unintentional adjustmentVSAvoidhandling difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking element transitions between a locked state (preventing rotation) and an unlocked state (allowing rotation). This dynamic capability enables the mechanism to provide secure protection during transport while allowing easy operation during assembly and maintenance, resolving the contradiction between security and ease of operation

Inventive Principle:
Principle #15Dynamics

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

The solution effectively secures the wave gear against unintentional adjustments during transport and assembly, ensuring a defined angular relationship for assembly and preventing motor attachment until the locking ring is removed, suitable for both manual handling and automated production lines.

Implementation Method 1

interacts positively with one of the three connecting elements and frictionally with a further connecting element

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3911845B1Harmonic drive
Publication Date: 2024.02.21 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3911845B1 patent drawingFigure 1
  • EP3911845B1 patent drawingFigure 2~3

AI summary

A harmonic drive (1) comprises three connection elements (2, 9, 12), namely an input element (2), an output element (13) and an adjusting element (9), and an antitwist mechanism (15) operates between the connection elements (2, 9, 12), the antitwist mechanism comprising an antitwist element (18), which is concentric to the connection elements (2, 9, 13) and interlockingly cooperates with one of the connection elements (9) and frictionally cooperates with one other connection element (2).