Hydraulic Camshaft Adjuster Spring Positioning

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Solution Overview

Problem

Hydraulic camshaft adjusters face issues with unstable operation and increased component wear during engine startup due to insufficient hydraulic pressure, leading to undesired vibrations and noise, and existing solutions require additional installation space or complex locking mechanisms.

Innovation Solution

Incorporating a mechanical spring element within the pressure chambers of the camshaft adjuster, which allows for the conversion of forces into adjustment moments without requiring additional space or components, and can be designed to assist in locking the rotor at desired rotational angles, reducing the need for external locking devices and minimizing installation space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If hydraulic pressure is used to position the rotor, then the camshaft adjuster can be controlled precisely, but during engine startup insufficient pressure causes unstable operation and vibrations

Engineering Contradiction:

Improvecontrol time precisionVSAvoidoperation stability during startup

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The spring element is pre-loaded to automatically position the rotor in a safe range during engine startup before hydraulic pressure is sufficient. This preliminary mechanical action ensures stable operation during the critical startup phase when hydraulic pressure is insufficient.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The spring element acts as an intermediary between the rotor and the hydraulic system, providing supplemental positioning force during startup. It bridges the gap when hydraulic pressure alone is insufficient, working in conjunction with the hydraulic medium to achieve reliable rotor positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If mechanical locking devices are added to prevent unstable operation, then reliability improves, but device complexity and installation space requirements increase

Engineering Contradiction:

Improveoperation stability during startupVSAvoidlocking mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The spring element is integrated within the existing pressure chamber volume, merging the mechanical positioning function with the existing hydraulic system structure. This combination eliminates the need for separate locking devices while maintaining reliability during startup.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The spring element serves multiple functions: it provides preliminary rotor positioning during startup, assists hydraulic pressure in maintaining rotor position, and works with the locking pin to enable reliable locking. This multi-functionality reduces the need for additional dedicated components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If additional locking pins and control mechanisms are implemented, then locking reliability improves, but the installation space and device complexity increase

Engineering Contradiction:

Improvelocking position reliabilityVSAvoidinstallation space

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The spring element is nested within the existing pressure chamber volume, utilizing the same space already allocated for hydraulic medium. This nesting approach allows the mechanical positioning function to be added without increasing the overall adjuster volume or requiring additional installation space.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 mechanical spring element ensures the rotor is positioned correctly for locking, reducing vibrations and noise, and allows for efficient use of existing installation space, while maintaining the hydraulic medium's functionality and reducing frictional contact issues.

Implementation Method 1

Incorporating a mechanical spring element within the pressure chambers of the camshaft adjuster, which allows for the conversion of forces into adjustment moments

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

when the internal combustion engine starts up, under some circumstances sufficient pressure of the hydraulic medium cannot be provided

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentUS7703426B2Hydraulic camshaft adjuster

Publication Date: 2010.04.27 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A camshaft adjuster for an internal combustion engine with a locking element is provided. For adjusting the camshaft adjuster (1) in the direction of a locking position, for example, when the internal combustion engine is switched off or when the hydraulic pressure drops, a mechanical spring element (23) is located between the rotor (5) and stator (3). The mechanical spring element (23) is arranged in a pressure chamber (12; 13). In this way, the installation space already existing for the pressure chambers (12; 13) can have a multifunctional use.