Cam Phaser Rotor Coupling for Axial Length Reduction

Solution Overview

Problem

Existing variable camshaft timing systems in internal combustion engines face complexity and leakage issues due to the need for seals between the camshaft and housing in hydraulically-actuated camshaft phasers, which complicates the configuration and increases axial length and torsional loads.

Innovation Solution

A hydraulically-actuated camshaft phaser design that includes a rotor with radially extending vanes forming fluid chambers, a housing that can change angular position relative to the rotor, and a camshaft sprocket with teeth engaging an endless loop, allowing for indirect linkage to change the angular position of the camshaft relative to the crankshaft without a direct seal between the camshaft and housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal is used between the camshaft and housing in hydraulically-actuated camshaft phasers, then hydraulic fluid containment is improved, but device complexity and axial length increase

Engineering Contradiction:

Improvehydraulic fluid containmentVSAvoidconfiguration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The rotor is merged with the camshaft sprocket through direct coupling, eliminating the need for a separate seal between the camshaft and housing. The rotor extends to the outer periphery of the sprocket, creating an integrated structure where the hydraulic fluid is contained within the rotor-vane-sprocket assembly without requiring additional sealing components between the camshaft and housing.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotor serves multiple functions: it acts as both the rotating element for hydraulic actuation and as the structural component that couples with the camshaft sprocket. This multi-functionality eliminates the need for separate sealing components, as the rotor itself provides both the hydraulic containment boundary and the mechanical coupling interface.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a seal is used between the camshaft and housing, then hydraulic fluid containment is improved, but axial length increases

Engineering Contradiction:

Improvehydraulic fluid containmentVSAvoidaxial length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The rotor is merged with the camshaft sprocket through direct coupling, eliminating the need for a separate seal between the camshaft and housing. The rotor extends to the outer periphery of the sprocket, creating an integrated structure where the hydraulic fluid is contained within the rotor-vane-sprocket assembly without requiring additional sealing components between the camshaft and housing.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a seal is used between the camshaft and housing, then hydraulic fluid containment is improved, but tolerance to torsional loads decreases

Engineering Contradiction:

Improvehydraulic fluid containmentVSAvoidtolerance to torsional loads

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The rotor is merged with the camshaft sprocket through direct coupling, eliminating the need for a separate seal between the camshaft and housing. The rotor extends to the outer periphery of the sprocket, creating an integrated structure where the hydraulic fluid is contained within the rotor-vane-sprocket assembly without requiring additional sealing components between the camshaft and housing.

Inventive Principle:

Principle #5Merging (Combining)

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 design simplifies the configuration, reduces axial length, and enhances tolerance to torsional loads by eliminating the need for a seal between the camshaft and housing, while maintaining the ability to adjust camshaft timing effectively.

Implementation Method 1

a rotor, coupled with the camshaft sprocket to prevent angular movement between the camshaft sprocket and the rotor, that includes one or more vanes extending radially outwardly forming a plurality of fluid chambers

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Gradient

Data Source

PatentUS10865664B2Cam phaser camshaft coupling

Publication Date: 2020.12.15 BORGWARNER INC

AI summary

A hydraulically-actuated camshaft phaser includes a camshaft sprocket having a plurality of teeth configured to engage an endless loop that transmits angular motion from the crankshaft to the hydraulically-actuated camshaft phaser; a rotor, coupled with the camshaft sprocket to prevent angular movement between the camshaft sprocket and the rotor, that includes one or more vanes extending radially outwardly forming a plurality of fluid chambers; and a housing that selectively changes angular position relative to the rotor and the crankshaft and is configured to be linked with a variable phase camshaft to change the angular position of the variable phase camshaft relative to the crankshaft.