Axially Compact Coupling Adapter for Camshaft Phaser Misalignment

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Solution Overview

Problem

Existing electrically driven camshaft phasers with harmonic gear drive units face challenges due to the need for axial alignment between the electric motor and the gear drive unit, which limits compactness and increases the axial length, and vane-type camshaft phasers suffer from low response at low engine speeds and high viscosity issues.

Innovation Solution

An axially compact coupling adapter is introduced, allowing for misalignment between the electric motor and the gear drive unit's input gear member, using a coupling with opposing drive lugs and slots that accommodate a press-fit bearing, enabling compactness and flexibility in alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the electric motor is rigidly coupled to the harmonic gear drive unit with strict axial alignment, then the connection is simple and strong, but the axial length increases and misalignment cannot be accommodated

Engineering Contradiction:

Improvealignment flexibilityVSAvoidaxial length

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The coupling adapter incorporates a misalignment feature that allows dynamic adjustment and accommodation of angular misalignment between the electric motor shaft and the harmonic gear drive unit input shaft. This enables the system to adapt to alignment variations without requiring strict pre-alignment, thereby reducing the axial length while maintaining operational flexibility.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The coupling adapter serves as an intermediary component between the electric motor and the harmonic gear drive unit. It includes a misalignment feature that mediates the connection, allowing for angular misalignment compensation while maintaining a compact axial design. This intermediary structure enables both alignment flexibility and compactness simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a coupling adapter with misalignment feature is used, then alignment flexibility is improved and axial length is reduced, but the device complexity increases

Engineering Contradiction:

Improvemisalignment accommodationVSAvoidcoupling structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The misalignment feature is merged into the coupling adapter structure itself, combining the alignment compensation function with the existing coupling components. By integrating the misalignment accommodation capability directly into the coupling adapter rather than adding separate mechanisms, the patent reduces overall device complexity while maintaining adaptability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The coupling adapter is designed with multi-functionality, serving both as a connection element and as a misalignment compensation mechanism. This universal design allows a single component to perform multiple functions (connection and alignment adjustment), thereby reducing the need for additional specialized components and lowering overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If drive slots are positioned axially away from the bearing press fit surface, then misalignment is accommodated, but the axial length increases

Engineering Contradiction:

Improvemisalignment toleranceVSAvoidcoupling adapter axial length

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

Instead of accommodating misalignment through axial displacement (increasing axial length), the patent uses the radial dimension by positioning drive slots axially coincident with the bearing press fit surface. The misalignment accommodation is achieved through radial clearance and angular adjustment capabilities in the coupling adapter, thereby maintaining compact axial length while providing misalignment tolerance through dimensional optimization in other directions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8800513B2Axially compact coupling for a camshaft phaser actuated by electric motor

Publication Date: 2014.08.12 DELPHI INT OPERATIONS LUXEMBOURG SARL

AI summary

A camshaft phaser includes a housing with a harmonic gear drive unit disposed therein. The harmonic gear drive unit includes a circular spline and a dynamic spline, a flexspline disposed within the circular spline and the dynamic spline, a wave generator disposed within the flexspline, and a rotational actuator connectable to the wave generator. A coupling adapter is disposed coaxially within the housing bore and fixed to the wave generator and supported in the housing by a bearing which is press fit onto a bearing surface of the coupling adapter. The coupling adapter has a coupling adapter bore with opposing drive lugs extending radially inward therefrom which are axially coincident with the bearing surface. A coupling of the rotational actuator is disposed within the coupling adapter bore and has opposing drive slots which receive the opposing drive lugs, thereby transmitting motion from the coupling to the coupling adapter.